Showing posts with label Scepticism. Show all posts
Showing posts with label Scepticism. Show all posts

11 March 2016

Freewill is Back on the Menu

“There is now no safer occupation than talking bad science to philosophers, except talking bad philosophy to scientists.”

- Mary Midgley.

I don't find freewill a particularly interesting problem, but it does come up from time to time. Because it is essential to Buddhist ethics, I've ended up writing about it a few times despite my reluctance, mainly to try to counter what I see as a pernicious trend to Determinism amongst Buddhists influenced by Advaita Vedanta. My essays on the subject include: Do We Have Freewill?(6 Feb 2015), A Sutta on Freewill Experience and Free Will in Early Buddhism (4 Apr 2014). The problem has become a cause célèbre amongst scientists since the 1980s when Benjamin Libet (1916-2007) first published results of his experiments on the so-called "readiness potential". The correct interpretation of these experiments has always been hotly disputed, though Determinists seldom cite any dissenting voices when they reference this material (so readers might be unaware of the controversy). We have seen a number of physicists in recent years citing Libet in the media and in books for the general public as "proving" that there is no free will. But as Peter Clarke observes:
Despite the fame of the Libet experiment and its frequent acceptance in popular and semi-popular writings, it has been the subject of intense controversy. Indeed, most specialists in the philosophy of free will who have addressed the Libet claim have rejected it. (2013)
Philosophers and physicists seem to fall out in public quite often these days. See, for example, Goldhill (2016) for a typical complaint about facile arguments from prominent physicists on the subject of philosophy. Physicists seem to take a perverse delight in dismissing philosophy out of hand, but often show their deep ignorance in the process. Stephen Hawking infamously declared philosophy dead. Paraphrasing Goldhill, this is a very stupid thing for a very smart person to say. Which just goes to show that smart people do make mistakes and do say stupid things. We can't just abdicate the responsibility for evaluating what people say, even when they are experts. As Richard Feynman said, "science is the belief in the ignorance of experts". And if we are not in a position to judge, then we can always seek out those who are and get their opinion. Unfortunately, physicists are often seen as authorities and thus their views on philosophy are widely taken seriously, even when they are out of their depth and saying stupid things. 

In this essay, sparked by a blog by Deric's MindBlog, I will outline Libet's findings, explore some responses from other scholars, and look at the philosophical implications. We might not be able to put to rest the wailing of "there is no free will" by Determinists, but we can at least give them something to chew on for a while.

Libet's Experiments

Libet was investigating the phenomenon of readiness potential (RP). The RP is a slowish build up of electrical potential in the brain, measured at the scalp over the motor cortex by an electroencephalograph (EEG). It occurs a second or more before people make voluntary movements. As the name suggests, this build up of electric potential was assumed to be the brain "getting ready" to initiate a movement. Libet was interested in the timing of the RP and the decision to move.

Libet's classic experiments (Libet 1985, Libet et al. 1983) asked people to make a simple movement, usually flexing their hand or wrist. The subjects were instructed to move whenever they felt like it (within a 20 sec window). At the same time they observed the position of a spot moving in a circle on an oscilloscope screen and reported the position of the spot when they felt the "urge to move". What he found was that there was a delay of some 200 milliseconds (ms) between becoming consciously aware of an urge to move and the actual movement. However, the readiness potential began to build up 350-500 ms earlier.

Note, this is a very short-range phenomenon. The voltage measured on the scalp is in the order of a few micro-volts (10-6 V). The amplitude drops off sharply. Another few centimetres from the scalp and the electrical activity would be undetectable (so no, this is not a mechanism for telepathy!). Indeed, one of the drawbacks of EEG for measuring brain activity is that it doesn't detect electrical activity below the cortex layer. The technique is also poor at localising the activity - multiple electrodes and sophisticated analysis of the activity can improve this, but EEG is still a pretty blunt instrument. The technique is famous for the early discovery that the activity in the cortex occurs in waves.

Libet controversially interpreted the initiation of the readiness potential as the "decision" to move, the point where the brain unconsciously began preparing to move. Becoming conscious of an "urge to move" came significantly later, and then, finally, the action itself was initiated, the whole process taking almost half a second. In this interpretation, the experience of willing our hand to move comes quite a long time after the brain has decided to move. In other words, the experience of willing our hand to move is a secondary feature in the process. Hence, freewill, interpreted as contra-causal freewill, is not what initiates a voluntary movement.

Contra-causal Freewill

I was alerted to idea of contra-causal freewill by reading Patricia Churchland's book Touching A Nerve: The Self as Brain (2013) in which she argues against it. Contra-causal freewill is the idea that we have an abstract capacity called "will" that is like the executive branch of the abstract capacity of "reason". To be considered contra-causally free, this capacity to make decisions or initiate actions must be free from any influences other than itself. Specifically, emotions, motivations, desires, goals, and knowledge must be excluded as potential influences. If any of these influence our decision making then, in this view, our will is not free. Thus for Libet, if some unconscious part of the brain is making the decision to move and then placing the idea in our conscious minds, then even though our brain is still making a decision, it does not count as free will because it is not based on the abstract reasoning capacity.

Any long time readers of this blog will know that this definition of free will is suspect at best. There are two main problems with it. Firstly, the definition makes an egregious mistake in considering reason to be an abstract capacity. I follow Lakoff and Johnson in taking reason to be a function of an embodied mind. Reasoning specifically uses metaphors grounded in our experience of the world to enable abstraction. It is not that we have an abstract capacity for reason, but that we have an embodied capacity for abstraction. Research by Antonio and Hannah Damasio (amongst others) has shown that emotions are involved in all decision making. As I have explained it, emotions tell us how salient any fact is to our decision making process (see Facts and Feelings, 25 may 2012). There is simply no plausible way for contra-causal freewill to operate. Secondly, the definition involved legacy understandings of how reasoning works. I also follow Mercier and Sperber in seeing reasoning as an argumentative capacity. It is well known that individuals are generally very poor at reasoning tasks. Most of us do not to make rational decisions and when we try to, we almost inevitably fall into cognitive bias or logical fallacy. On individual tests of reasoning, we frequently score worse than random guessing. The long lists of cognitive biases and common logical fallacies that we are prone to bear stark witness to this. Reasoning is not activated until we are assessing someone else's argument or retrospectively justifying our own actions (see An Argumentative Theory of Reason, 10 May 2013). 

As Churchland has said, contra-causal freewill is not particularly interesting. Even if the experiment showed that we do not have contra-causal freewill, this would still not be interesting as the concept is a legacy of a bygone era that has no place in modern discussions about the mind or morality. Clearly, many scientists are poorly informed on developments in philosophy because they think philosophy is worthless. They cannot be relied on, in general, to be guides to the philosophy of freewill. This is an important caveat when considering this question. My suspicion is that the criticism cuts both ways. That as much as philosophers like to comment on science, they are often too poorly informed about it to be trustworthy guides to it. All too many philosophers in this field seem to be ontological dualists who do not believe that studying neurons can tell us how the mind works, for example. Sorting out whether or not any individual commentator on this issue makes sense is really quite difficult. No doubt I am also a poor guide to this issue. However, other scholars have been trying to reproduce Libet's experiments and assessing his interpretation of the results since it was published. And we can turn to them to get some balance.

Re-evaluating Libet.

As I say, the interpretation of Libet's experiments has been the subject of intense controversy since they were first published. It seems, from my outsider point-of-view, as though physicists have lined up to say that they prove that human beings are Deterministic and that there is no freewill. But even casually reading around this subject we see that philosophers have lined up to deny that Libet tells us anything about freewill.

For example, what exactly is a voluntary movement? Peter Clarke (2013), for example, cites the example of a tennis player serving a ball. The decision to serve may be voluntary and the movement of the arm might even be partially under conscious control, but the myriad movements that coordinate the whole body as it moves and balances to support the motion of serving are almost entirely unconscious. The motions that direct the ball to the precise location on the opposite player's court are mostly not under the direct control of the player. Tennis players have developed a kind of reflex that allows them to serve accurately at speeds that does not require conscious thought. Indeed, in many sports, we know that thinking too much about key muscle movements is counter-productive. So, is serving the ball a voluntary act? I get this playing the guitar. I train my fingers to find and pluck the notes I want so that I don't have to think about them and this enables me to sing at the same time. If I was consciously seeking out notes on the fretboard and dredging up lyrics and all the other components of articulation and delivery, I could not play the simplest tune, let alone something as complex as, say, the Beatles' tune Blackbird. The assumption that a decision to act cannot occur without being conscious of it is deeply problematic. In playing a tune like Blackbird, I initiate hundreds of actions with no consciousness of doing so because my attention is usually elsewhere. So this question is far from trivial and it ought to make us pause before considering what it means for an experimental subject to make a "voluntary movement". Even if Libet relies on a single movement, how do we know that this is representative, or that the experiment is able to isolate that movement from everything else that is going on in a conscious subject?

An important criticism of the Libet experiment is that it is very difficult to judge when one experiences the "urge to move". Clarke (2013) did the experiment himself and commented "When I try this, I find it very hard to judge the precise time when I decided to move my finger / wrist." Clarke describes studies on the reliability of the subjective timing of events which have shown it to be very imprecise. Additionally, the experiment involves an attention shift from the movement to the timing that "may have introduced temporal mismatches between the felt experience of will and the perceived position of the clock hand." Attempts to eliminate this mismatch have shown that the RP occurred before the "urge to move" only in about two thirds of subjects. To try to improve accuracy, the experiment was performed using functional magnetic resonance imaging (fMRI) and this also showed that "the activity of prefrontal and parietal cortex was correlated with the decision [to move] with 60% prediction accuracy, up to 10 sec before the conscious decision." These findings seem to say that there cannot be a causal relationship between the RP and the "urge to move", else it would occur every time. In which case Libet appears to have misinterpreted what the RP is.

Clarke (2013) lists a number of other published criticisms of the Libet experiments. Firstly, Libet takes the RP to represent a decision to move; i.e., he believes that there is a causal connection between the beginning of the RP and the action, if and when it comes. However, it appears that there is no neural connection between the areas that build up potential in the RP (the sensory motor-cortex) and the parts of the brain associated with decision making (in the parietal lobe). Thus, in addition to there being a disconnect in practice, there is no obvious mechanism for the RP to cause the urge to move, either.

Secondly, if the RP was the cause of the movement, then we would expect a strong correlation between the timing of the onset of RP and the timing of the urge to move. But this correlation does not occur. Experiments to test this seem to rule out the RP as cause of the urge to move, though not of the movement itself. So, at the very least, the mechanism proposed by Libet has a missing link. And that link might play an active role in the process (i.e., might be directly causal).

Alfred Mele offers a third criticism of the Libet experimental set up, noted by Clarke (2013). In Libet's experiments, the data was only stored when a movement is initiated. Libet collected no data on what happened if the subject decided not to move. This vitiates his finding because it's entirely possible to prepare to move, which would presumably initiate an RP, and then not experience the urge to move. If an RP can exist and not give rise to an urge to move, then RP may not related to the urge to move at all. This possibility ought to have been excluded, but was not. A variation on the experiment by Trevena and Miller did collect data on cases where the decision was made not to move. The RP was the same whether they moved or not. And this suggests that RP does exist without giving rise to the urge to move, or an action, which undermines Libet's conclusion that RP represents a decision to move. 

A fourth weakness was pointed out by Hermann, et al. They set the experiment up as a decision to press one of two buttons in response to a stimulus. They also found the RP appearing before the urge to move occurred, but the RP occurred even before the stimulus appeared and thus is unlikely to have been related to a decision about which button to press. Again, the evidence points away from a coupling of RP and the urge to move. In fact, Schurger, et al (2012) showed the decision to move occurs very late in the course of the RP, not at the initiation of it.

Libet himself argued that his interpretation showed that, although freewill in the sense of consciously initiating actions was ruled out, we still had the option of inhibiting actions between the initiation of the RP (what he called the decision to move) and the urge to move. Some people called this "free-won't". This might be an interesting thread to follow up, except that considering the various critiques of Libet's experiment and interpretation, it seems that treating the initiation of the RP as the decision point makes no sense.

The real nail in the coffin, however, was published in Feb 2016 (just a couple of weeks ago as I write this). Libet was focussed on spontaneous voluntary movements (SVM) and it turns out that these are rather different in their underlying dynamic than movements initiated in response to a stimulus. Citing from Deric Brown's blog:
"A new generation of experiments is now suggesting that brain activity preceding spontaneous voluntary movements (SVMs) 'may reflect the ebb and flow of background neuronal noise, rather than the outcome of a specific neural event corresponding to a ‘decision’ to initiate movement... [Several studies] have converged in showing that bounded-integration processes, which involve the accumulation of noisy evidence until a decision threshold is reached, offer a coherent and plausible explanation for the apparent pre-movement build-up of neuronal activity.'" (Shurger et al. 2016)
So what looks like a build up of "readiness potential" is, in fact, happening because of anticipating having to make a decision at some point (and in the experiment the subject is explicitly primed to do so). The actual decision is reached when background neural activity reaches a peak:
"In particular, when actions are initiated spontaneously, rather than in response to a sensory cue, the process of integration to bound is dominated by ongoing stochastic fluctuations in neural activity that influence the precise moment at which the decision threshold is reached. ... This, in turn, gives the natural but erroneous impression of a goal-directed brain process corresponding to the ‘cerebral initiation of a spontaneous voluntary act’"
In other words, if we look again at the graph of "readiness potential" the decision to move comes at the peak of neuronal activity not at the onset of the RP. The RP is an accumulation of more or less random neuronal activity. This would explain some of the contradictory results mentioned above.

But, crucially, what this suggests to me is that the urge to move precedes the decision to move. The urge to move may, in fact, be an important factor in the decision to move. So it seems that Libet's interpretation of his experiment was flawed in these various ways and that freewill is back on the menu.


I discovered this information because I happen to read a number of neuroscience blogs and Twitter feeds and one of them happened to mention this new article by Shurger et al. (2016) which drew me into the subject anew. But there was always debate. Over what freewill means. Over what the readiness potential represents. Over the causal relationship between the readiness potential and the urge to move; or between the RP and the actual movement. Over Libet's experimental methods.

This experiment is so often presented with a one-sided interpretation, with no mention of the mass of contradictory evidence that make Libet's interpretation look doubtful. There is no mention of the intense debate that has ensued. Any reader could be forgiven for thinking that it was an open and shut case or that Libet had definitively shown that freewill could not exist. But this was never the case. The interpretation of the experiment could never be considered unequivocal proof of anything. The weakness of Libet's experimental design and the many contra-indications for Libet's interpretation of the readiness potential as a decision or even as causal, ought to have been given more prominence in the discussion of freewill.

Most scientists are aware of the problem with "proving" an hypothesis anyway. As Karl Popper observed, an hypothesis can really only be disproved or a conjecture refuted. A scientific theory may make more or less accurate predictions. For example, the Higgs Boson has not in fact been proved to exist. However, the theory (The Standard Model of Particle Physics) did predict a particle would be found in a certain energy range and such a particle was found in the Large Hadron Collider. So the theory survives another test, and we now try to test other predictions that it makes. The theory could fail at any point, and many scientists hope that it does, because that would make their work far more interesting and open up the field to new discoveries. The failure of the Standard Model would initiate a golden age of inquiry into the nature of the universe. Scientists are frankly bored by the idea that everything has been discovered. Which is the opposite of how they are sometimes portrayed and the opposite of religious approaches to knowledge. 

When so-called scientists give a biased presentation of an issue, citing only the evidence for their interpretation and avoiding even mentioning that there is considerable evidence against it, then that is a kind of fraud. Scientists committing such fraud ought to be censured by their peers. False statements ought to be retracted. And I think in this area of freewill many scientists are guilty of this kind of fraud. And many laypeople have repeated the fraudulent claims and perpetuated a falsehood.

In this the public have been extremely badly served by lazy journalists who have simply failed to report the experimental evidence. Whether this also amounts to fraud depends on your point of view. I see the primary function of journalism as being entertainment. Entertainers are always allowed some "poetic licence" to deceive us about facts if the version of events they present is more entertaining than reality. Hollywood films almost always distort history because the real story is often boring. Science journalists are a mixed bag and you never know which kind of story you are reading, but these days I just assume, with very few exceptions, that if a journalist is writing they are seeking to entertain rather than inform.

There will be those who cite this case as showing that the scientific method is broken. That in overturning a previous interpretation of the data science has proved that it cannot be trusted. To my mind, it says completely the opposite. This is science in action. This is the scientific process at work. The overturning of previous interpretations is part and parcel of embracing science. What we think we knew today is quite likely to be overturned tomorrow. For the religieux seeking certain knowledge and believing that they have found it, this seems anathema. That knowledge could be transient and contingent makes it seem untrustworthy. Religion is predicated on the idea of absolute knowledge, from which comes certainty, and relaxation, as all mysteries are resolved in the long run. But that is an impossible fantasy. In the real world, things are messy. Knowledge is never absolute. There is always the possibility of being wrong.

Religieux seem very uneasy with the idea that they might be wrong. Buddhists, in particular, seem to find this concept deeply troubling. Scientists, by contrast, embrace uncertainty and the principle that all knowledge may be overturned by a better explanation. Science progresses by testing ideas to destruction. This attitude of contingency with respect to knowledge of the world is, in fact, far more in keeping with Buddhist ideology. Most Buddhists appear to believe that the world can be understood in absolute terms, that the Buddha was omniscient in this sense, and that the Dharma is an expression of this absolute knowledge, i.e., that it represents absolute truth. They further believe that we can come to this absolute knowledge through introspection and believe that we cannot come to knowledge through examining the world. I have been told by a colleague, for example, that "no amount of study of the brain will ever tell us anything about the mind". Which is just Cartesian Dualism, as far as I can see, and thus a thesis that has already been soundly refuted.

However, despite having cast considerable doubt on the Libet interpretation, this is not the end of the story. There are other arguments against free will that are much more difficult to tackle than Libet's and his Determinist fans, for example, the argument by Sabine Hossenfelder on the Backreaction blog. I don't necessarily agree that arguments from fundamental laws eliminate the possibility of unexpected emergent properties that are indistinguishable from free will, but she still makes a strong argument for anyone who acknowledges the laws of physics. And so the arguments will go on. But as religieux we do need to be wary of pursuing a conjecture only because it supports our doctrine. Freewill is interesting because without it Buddhist ethics would be meaningless. If we seek only to bolster our view, rather than to seek the truth, then the possibility of being wrong is excluded and we are unlikely to accept that we have been wrong when the evidence becomes unequivocal. I see this happening in the area of the afterlife, for example. Intelligent people must always hold to the possibility of being wrong. But intelligent people are also the most reluctant to reconsider their considered views. Intelligent religious people are the worst. 



Alexander, P., et al. (2016) Readiness potentials driven by non-motoric processes. Consciousness and Cognition, 39: 38–47. doi:10.1016/j.concog.2015.11.011

Churchland, P. S. (2013) Touching A Nerve: The Self as Brain. W. W. Norton & Co.

Clarke, P. G. H. (2013). The Libet Experiment and its Implications for Conscious Will. Faraday Paper No. 17. Faraday Institute for Science and Religion.

Fried, I., Mukamel, R. & Kreiman, G. ‘Internally generated preactivation of single neurons in human medial frontal cortex predicts volition’, Neuron (2011) 69: 548-562.

Goldhill, O. (2016). Why are so many smart people such idiots about philosophy? Quartz. March 05,

Libet, B. (1985). Unconscious cerebral initiative and the role of conscious will in voluntary
action. Behavioral and Brain Sciences, 8: 529-566.

Libet, B., Gleason, C.A., Wright, E.W. & Pearl, D. (1983). Time of unconscious intention to
act in relation to onset of cerebral activity (Readiness-Potential), Brain, 106: 623-42.

Schurger, A., Sitt, J.D. & Dehaene, S. (2012) An accumulator model for spontaneous neural activity prior to self-iniated movement. Proceedings of the National Academy of Sciences. USA doi:10.1073/pnas.1210467109

Schurger, A. et al. (2016) Neural Antecedents of Spontaneous Voluntary Movement: A New Perspective. Trends in Cognitive Sciences, 20 (2), 77 - 79.

Additional reading

Fischborn, Marcelo (2016) Libet-style experiments, neuroscience, and libertarian free will. Philosophical Psychology. 1(9) doi: 10.1080/09515089.2016.1141399
"The general result is that neuroscience and psychology could in principle undermine libertarian free will, but that Libet-style experiments have not done that so far."

23 January 2015

There is No Life After Death, Sorry.

Is there life after death? This question has been important to people for at least 100,000 years. Now we can definitively say, "no, there isn't." What we know about how the universe operates rules out the possibility. You only live once. This can only be a disappointment to many people. On the other hand, now that the question is settled, we can get on with the serious business of deciding how we ought to live with this situation.

In this essay, I begin with a longish introduction in which I recap some important points made in previous essays about the idea of life after death. I look at the dynamics of afterlife beliefs and challenge the view that the concept of the afterlife is beyond the reach of empiricism. If you're familiar with my treatment of this material you can skip the intro. I then settle in to explore an argument made by theoretical physicist Sean Carroll which purports to show that no afterlife of the kind described by either Christianity or Buddhism is permitted by the laws of physics. I will finish by considering the ethics of debunking traditional beliefs and some reflections on our existential situation.

In October, 2014, Sean Carroll accepted the Emperor Has No Clothes Award, organised by the Freedom From Religion Foundation, and gave a short acceptance speech (watch the video). In this speech he says "We can say, there is no life after death... sorry". It so happens that in the same week I watched the video, one of my colleagues wrote something about our Buddhist teacher's belief in rebirth. She said that while he acknowledged that one couldn't prove or disprove rebirth, he himself was convinced on the basis of certain experiences he had had. My colleague said that if she'd had that kind of experience, she'd be convinced also. I'd say that this is fairly typical of the type of argument that Buddhists field for rebirth. There are two parts to this type of argument:
  1. the afterlife cannot be factually disproved; and that 
  2. anecdotes about experiences are convincing. 
In other words, I can't prove X, but I believe X, where X is any religious belief. This is just what my mum says about God, for example.

This problem of private experience being generalised into ontological conclusions is a perennial one for religions. When we try to draw valid conclusions about public reality from one-off private experiences we are apt to make mistakes; when those private experiences involve altered states of consciousness, then we almost always make mistakes. Our conclusions might feel right, but they've usually got more to do with what we want to believe than what reality is like. When someone is already convinced of a proposition, then any experience that supports the proposition will feel salient, and any experience which does not will feel irrelevant. The more the experience can be interpreted as supporting the belief, the more salient it will feel. A question I cannot yet address is why outlier experiences—drug induced hallucinations, religious visions, oceanic boundary loss—might seem more real than baseline reality, even hyperreal, rather than less real. The question of how real experiences feel is crucial to an overall understanding of how we value experiences.

The Dynamic of Afterlife Beliefs

As individuals trying to reason, we seem, almost inevitably, to fall prey to a wide variety of biases and/or logical fallacies. The explanation for the woeful performance of individuals on reasoning tasks put forward by Mercier & Sperber, says that as individuals putting forward an argument, we are powerfully, inherently, biased to select evidence and supporting arguments that support it. It is only in arguing against a proposition that we think to select counterfactual information. We seem to have evolved to reason in small groups where proponents make the strongest case for their favoured outcome, and opponents argue against it, and collectively the group selects a course of action which most appeals to the largest number (or to those with most influence). See An Argumentative Theory of Reason. In this view, the most common reasoning problem, confirmation bias, is a feature of reasoning, not a bug. It also means that reasoning doesn't work well in highly polarised situations or where everyone has strong beliefs that distort how they assess the saliency of information. Clearly, discussing religious beliefs with religieux is a situation where reason is likely to work poorly. So, one of the reasons we draw incorrect inferences about public reality from private experience might be that we are affected by religious views on top of our usual biases and fallacies. 

The argument put forward by Sean Carroll effectively says that an afterlife would be a kind of miracle because it breaks the laws of physics. Hume's essay Of Miracles gives us a useful criteria for assessing the testimony for miracles:
"No testimony is sufficient to establish a miracle, unless the testimony be of a kind, that its falsehood would be more miraculous, than the fact, which it endeavours to establish."
Anecdotally, many of my colleagues in the Triratna Buddhist Order find the falsehood of an afterlife more miraculous, less credible, than the testimony that there must be an afterlife of the Buddhist kind. Usually, the testimony in question is about outlier experiences that seemed hyperreal and are judged to be of extraordinary value and significance. For such intuitions about experience to be false would seem miraculous. Again, my mum has the same argument from experience for God.

One of the key points to understand is how we make decisions. While we do employ facts, there is research to show that we assign information a weight or a measure of salience at an emotional level. When faced with competing information about the same decision, we assess which information is salient to our decision by how it feels. We know this because people with specific damage in the mediodorsal-prefrontal cortex, which is involved in emotional regulation, lose the ability to weigh facts in this way. We make decisions based on what feels right and then find reasons post hoc. This is something the advertising industry has known for many years, dating back to the 1920s and the influence of Sigmund Freud's nephew, Edward Bernays. See for example, Torches of Freedom. The whole spiel about Homo sapiens (thinking people) having reason as our highest faculty is quite wrong. We're seldom any good at it. We emote our way through our lives with post hoc rationalisation to cover our tracks.

The idea of an afterlife is ubiquitous in human cultures. For a self-aware living being, whose raison d'être is continuity, the fact of inevitable death creates an intense cognitive dissonance. Apart from the obvious wish not to die, the afterlife also serves as a clearinghouse for reconciliation of our moral accounting records (which is why karma must keep track of our deeds): actions must fit consequences and, since they obviously don't in this life (aka the Problem of Evil), then they must in the afterlife. The afterlife is almost always tied to the idea of an entity which survives the death of the body and contains our essence (i.e., a soul). Certain types of experiences suggest that the perceiving mind can exist as a separate entity from the physical body. This leads to ontological dualism: to the assumption that matter and spirit are different types of stuff (see especially my essay Metaphors and Materialism; also Origin of the Idea of the Soul). I've cited this passage from Thomas Metzinger's book The Ego Tunnel several times, but it seems to be essential to understand this:
For anyone who actually had [an out-of-body experience] it is almost impossible not to become an ontological dualist afterwards. In all their realism, cognitive clarity and general coherence, these phenomenal experiences almost inevitably lead the experiencing subject to conclude that conscious experience can, as a matter of fact, take place independently of the brain and body. (p.78)
However, when studied closely, these experiences do not support ontological dualism or the idea that the mind is a separate entity or made from a different kind of stuff from matter. Buddhists also tend to describe their afterlife beliefs in dualist terms (partly because morality requires personal continuity to be coherent even across one life time, let alone many) and then add specific metaphysical caveats when challenged, so as to avoid violating Buddhist axioms that forbid persistent entities. These caveats vitiate personal continuity, and therefore morality, but this problem seems to go unnoticed. So the dynamic of afterlife beliefs is like this:
  • The fact of universal death creates cognitive dissonance. 
  • According to testimony, certain experiences appear to demonstrate that consciousness is not tied to the body, but can exist independently.
  • So the idea that something might survive the death of the body and continue to "live" seems plausible.
  • Emotional weighting of facts (salience) makes this seem probable, and the finality of death improbable.
  • Since the finality of death causes intense cognitive dissonance, post-mortem survival seems preferable.
  • We make the leap from probable/preferable to actually true; and it feels satisfying because we have resolved the dissonance created by the fact of death and been consistent with our other beliefs.
(Adapted from my 2012 essay on the plausibility and salience of rebirth.)
All that remains is for Buddhists to adapt this to avoid an unchanging entity, which we do by saying that any entity is conditioned and changes (and is this only conventionally or notionally an entity).

The Proposition that the Afterlife is Beyond Empiricism

The idea that one can neither prove nor disprove rebirth is a proposition formulated within a framework which is strictly dualistic in the Cartesian sense of an absolute distinction between matter and spirit. In this framework no empirical evidence is salient to the question of the afterlife, because it comes from the wrong realm: as one dualist Order colleague explained to me, in a mood of high dudgeon some years ago, "no study of matter, however thorough, can tell us anything at all about consciousness." The afterlife, being concerned with the realm of spirit, is not accessible to empirical methods.

The problem here is one of definitions. The dualist defines the afterlife in dualistic terms. Those terms include the explicit assumption that empirical methods don't apply to the spirit realm. If one accepts the dualistic frame of reference, then there can be no argument. The afterlife is axiomatically beyond empiricism. But the definition is circular. Empiricism cannot see the afterlife only because we have defined the afterlife as invisible to empirical methods.

Buddhist texts certainly do not define the afterlife as invisible. Indeed, one of the memorable visions of my own teacher involves seeing pretas in their pretaloka. How can we possibly explain this leakage from the spirit realm into the realm of matter? If it is possible to see pretas, then they ought not to be invisible to empiricism. Why do we allow dualists the luxurious the exception that some people can see spirits and yet disallow empiricism? We will develop this line of enquiry below.

A more fundamental question is this. Why should we accept the dualist definition in the first place? Buddhists tend to argue from testimony about experience: especially from so-called "spiritual experience". One of my teachers tells me that, based on his "meditative experience", he cannot imagine there not being an afterlife. But, once again, we're in the territory of making inferences about reality from unusual private experiences. To take a non-Buddhist example, Gary Weber, who vividly describes his awakening experience in terms easily recognisable from traditional Buddhist accounts, insists on the basis of his experience that the universe is absolutely deterministic and that free will is an illusion! Why? Because his main teachers are proponents of Advaita Vedanta and this is their doctrine. Weber describes how free he is and, in the same breath, denies that he is free at all. It appears that even the awakened are not to be trusted to tell us about reality.

I've put considerable effort into undermining the idea of dualism. I've tried to show that it is not credible and does not produce meaningful predictions. Dualism is a bad theory. Monistic theories, by contrast, continue to make predictions about how the mind operates that turn out to be accurate. (See, for example, this article on ghosts). Sean Carroll's argument will take this a step further. The dualistic matter/spirit framework has nothing to do with Buddhism. I've tried to show that such matter/spirit dualism is an ontological conclusion that is not supported by the epistemology of Buddhism.

I should add that many, but not all, of the people who are involved in this argument on the dualist side are, at best, poorly educated in the sciences. Their understanding of science is frequently a caricature. But they are egged on by people who should know better, whose attraction to dualism has overcome their education. A clique of social scientists with axes to grind about objectivism is also involved, who muddy the water by attacking the very idea of objective knowledge. To these last, Sean Carroll has a witty repost on his Twitter profile: "If the blind dudes just talked to each other, they would figure out it was an elephant before too long." I used this as the starting point for a meditation on whether experience really is ineffable. Too many philosophers are solipsistic. They do philosophy as though one cannot talk to another person or compare notes on experience, or as though this is not a valid source of knowledge. Buddhists do this almost without fail, and it hobbles their ability to think about the world.

As Sean Carroll is quick to insist, empiricism comes with many caveats. We certainly cannot explain everything in the universe. Far from it. There are huge gaps. But science is an ongoing and progressive endeavour, and it is by far the most successful knowledge-generating activity in the history of knowledge. The shift in knowledge just in my lifetime has been staggering. One of the ironies of arguing with dualists is that they invoke the limitations of empiricism: you cannot explain everything. True. But why does that open the door to any old interpretation that happens to appeal? What ever happened to saying "I don't know"?

This is perhaps enough background for newer readers to allow us to proceed to considering the proposition that there is no afterlife. 

Sean Carroll's Argument

Carroll's argument begins with a series of propositions: 
  1. The mind is the brain. 
  2. The brain is made of atoms. 
  3. We know how atoms work. 
  4. When you die there is no way for the information that was you to persist.
We'll work through these assertions as he does, with a few extra comments thrown in.

1. The mind is the brain

The brain is the mind in space, and the mind is the brain over time. 
Past experience shows that dualists are already switching off, if they are reading at all. Carroll is what they call a "materialist" and what I would call a substance monist. Indeed, his view (as he says in the video) is that Quantum Field Theory accurately describes reality: reality is fields. All the reliable evidence we have points to a universe composed of fields. When we look at these fields the nature of them means that what we actually see is matter and energy. After centuries of studying matter in controlled ways there is no behaviour of matter and energy, at the scale relevant to the functioning of human beings, that has been observed under controlled conditions, which requires extra laws of physics. Thus, the only sensible philosophical view is monist. We might not know how the mind works, but we have no reason to propose some other thing that can interact with matter. This will become a refrain: if it can interact with matter we'd have detected it by now. In this view the mind is a function rather than a thing or stuff. The mind is what the brain does.

However, we have a legacy view which is dualist. This legacy is probably as old as anatomically modern humans and it says, mainly on the basis of interpretations of private experiences, that the mind not made of the same stuff as the rest of the universe. The view is that there is a stuff we might call "spirit" that makes up an invisible and intangible "world of spirit" in parallel to the world of matter and energy, and that this spirit animates our bodies (which are otherwise cold dead matter). We now have secular versions of this dualism which argue that experience cannot be explained in monist terms, famously associated with Dualist philosopher David Chalmers and the so-called "Hard Problem of Consciousness". However, all dualism does is deflect the Hard Problem, it does not answer it. What's worse, is that it defines the Hard Problem as insoluble, because the stuff that consciousness is made of cannot be an object of study. Game over for science.

Invoking an invisible and intangible stuff that somehow undetectably also interacts with matter and energy to make us alive and conscious is not logical. Either the second stuff interacts with matter and energy and can be detected in the usual ways, or if it cannot be detected in the usual ways then it cannot interact with matter and energy. If it does not interact with matter and energy, then, for example, we could not see it or hear it the way that people claim to. Equally, a "body" made of this second stuff could not see or hear, either. A subtle body would either be completely unable to interact with the world (to see it, hear it, feel it) or we would be able to detect it. There are no other options.

1.1 Objections

One objection sometimes put forward is that the brain is not complex enough to generate consciousness. I think we still have legacy issues with the concept of "consciousness", which the study of ancient Buddhist thought only highlights, since it conceives the mind in entirely different terms. Even so, the complexity of the brain is effectively unimaginable: 100 billion neurons with an average of 1000 connections each, can generate 10,000,000,000,000,000,000,000,000 unique states. There is no question of the brain being complex enough.

Some who reject Carroll's first proposition try to explain consciousness using the brain as TV receiver analogy. In this, the brain is still necessary for consciousness, but it is a passive receiver of a "signal" from "beyond" the physical world. This is ruled out by Sean Carroll's friend, neuroscientist Steven Novella. He argues that to compare the brain to a TV that simply displays the information beamed into it, is a false analogy.
A more accurate analogy would be this – can you alter the wiring of a TV in order to change the plot of a TV program? Can you change a sitcom into a drama? Can you change the dialogue of the characters? Can you stimulate one of the wires in the TV in order to make one of the on-screen characters twitch? - The Brain Is Not a Receiver.
Disrupting the reception of the "signal", via, say, brain damage, does not simply distort the image of the show, it changes the plot and the characters. The brain simply cannot be a passive receiver. The brain is actively involved in creating consciousness. This is the only way to explain the correlations that we observe. Correlation is not causation, except when it is.

In fact, I slightly disagree with Sean in this area. I think the mind is created by the body as a whole. Certainly, the brain is the concentrated centre for the operation of mental events, but the mind function involves all of our body's systems: neural, endocrine, sensory etc. Our minds arise as an emergent property of being embodied in the way that we are. Our minds are defined, not simply by where signals are processed, but by how they are generated and transmitted. They are defined by the fact that brains clearly evolved to better direct the actions of bodies.

Those who propose a dualist explanation complain that "Materialists" refuse to accept evidence for the second stuff, that they refuse to even look for it; that Materialists scorn research which proves the paranormal, the supernatural, and all that stuff. In fact, scientists do take an interest from time to time and when such phenomena are explored under the rigorous eye of scientific method they inevitably fade from view or quite often turn out to be hoaxes. In fact, huge efforts have been made to validate ESP under laboratory conditions and it doesn't exist. On the other hand, modern day magicians like James Randi and Derren Brown have shown exactly how to spoof many of these effects. One of the originators of the Victorian seance, the Fox Sisters, confessed to their hoax late in life, though this did nothing to dent the popularity of talking to "the other side". The trouble is not that scientists are not interested in evidence for the supernatural, but that believers are too credulous and set the evidential bar too low. They are too willing to ignore debunking and exposure of hoaxes. I know many people who openly want the world to be magical or mystical; who openly and consciously suspend disbelief because they don't want to believe the evidence. Scientists make their reputations by making new discoveries and/or showing how old discoveries have been misinterpreted. Einstein is famous precisely because he overturned the existing paradigm and gave us a completely new way of looking at our world. No one ever got a Nobel Prize for science while ignoring interesting evidence for some new way of looking at the world.

As unpalatable as it sounds, Sean Carroll's bald statement that the mind is the brain, is not far from the truth. I would say that the mind is the body; or better that the mind is a function of the processes that make up the body. We will have more to say on why this must be so under statement three, but for now let us move on to the second statement:

2. The brain is made of atoms

This, I hope, will be fairly uncontroversial. We've been analysing matter for a long time now, we know what all the elements are and how they behave on a gigameter-scale and nanometer-scale (the mysteries are on a tera- and pico- scale and beyond). We understand the chemistry of all naturally occurring atoms (and a handful of synthetic atoms) and can explain the properties of known substances in terms of the properties of these atoms with incredible accuracy. We know how atoms combine into molecules and can predict the properties of new molecules from which atoms they contain. We know how molecules interact to create emergent properties. My bachelors degree was in chemistry, so I'm confident about this. 

Of course, the dualist can still posit super-natural substances or forces that are involved in the structure of the body and brain, substances and forces that are beyond the reach of empirical science, but our refrain still applies: if these supernatural substances or forces interact in any meaningful way with atoms, then we can detect them; if we cannot detect them, then they cannot interact in meaningful ways. Millions and millions of experiments, from detailed observations of our solar system down to the manipulation of single atoms, have failed to find any behaviour of atoms that cannot already be explained. Which leads us to statement number three. 

3. We know how atoms work

Carroll admits that this is controversial. His point is not that we understand all the laws of physics, nor even all the laws that govern atoms. What he is saying is that the laws that are relevant to the functioning of our minds and bodies are known. He adds, "There no room for new laws of physics that would affect how the atoms in your brain actually work". And here is a summary of those laws of physics in one intimidating equation:

"In this one equation are summarised all the laws of physics necessary to understand the atoms in your brain [and body] at the energy, mass and length scales relevant to your everyday lives." 
For more on this equation see Sean's blog: The World of Everyday Experience, In One Equation. For anyone who would like to get into this material in even more detail, Sean has claimed that The Laws Underlying The Physics of Everyday Life Are Completely Understood. There are links on the blog to follow up posts. 

Now, I freely admit that I don't understand all of this. But I don't have to. I do understand enough of it to be confident that the rest of it is true, and I have personally tested out a proportion of these laws, especially where they relate to chemistry.

We don't know it all, by any means, but we know enough. As Sean says:
"If there are any other forces, particles, fields or phenomena they can't affect the atoms in your brain and body because either they are so weak that they could not affect the atoms, or we would have found them. Those are the only two options." 
So, for example, we might not understand dark matter, but dark matter has no appreciable effects on human beings. We could dive into a swimming pool full of dark matter and simply fall to the bottom without interacting with any of it. This is not so weird. Every second millions of neutrinos from the sun pass through our bodies, indeed pass right through the earth, without ever interacting with our atoms. Dark matter's effects are only evident on the scale of galaxies and clusters of galaxies. We might not fully understand the Higgs Boson, but it's only evident on the scale of subatomic particles accelerated to 99.99999% of the speed of light and smashed into each other or in the second or so after the big bang. The macro effect of the Higgs is gravity, which we can predict with astonishingly high accuracy using the science of Einstein. Indeed, Newton and Laplace will suffice for everyday use. Yes, there is a huge amount to learn, but it's at the extremes, not in the middle. As far as the human-scale world is concerned, "at the energy, mass and length scales relevant to your everyday lives," we understand it quite well enough to predict the behaviour of atoms at levels of precision well beyond what we can perceive.

Because this is the state of knowledge, it reinforces proposition one. If there were another stuff out there, or in here, that could affect our brains, we would have found it by now. The mind cannot be a different kind of stuff or we'd have found that stuff. There is nowhere for the mind to hide. This kind of argument, that something is hiding just beyond the detectors is what is known as a God of the Gaps argument. God, or the supernatural or whatever, is always just beyond the current state of our knowledge of the universe. But the picture of physics is so well worked out now, that there are no gaps big enough to fit the mind into it. If, for example, the mind turns out to be a product of quantum vibrations in micro-tubules in neurons, rather than the interaction of neurons themselves, it won't change the basic fact that the mind is the brain. And we understand the principles of quantum states too.

3.1 The Map is Not the Territory

Against this is "the map is not the territory" argument. It is true that our mathematical models are incredibly comprehensive and accurate, but this does not mean that we understand reality. As human beings we never have direct access to reality. By reality, we generally mean the facts about sense objects that are independent of our minds. Since our perceptions are always mediated by the brain, at best, we're operating at one remove from reality.

Against this limitation on individual perception is the fact we can compare notes on what we observe and use this to factor out the component due to individual minds. What is left is what the universe is like. Some dismiss this "consensus reality". What I'm thinking of is not just something that people agree to. The observations I'm thinking of compel us to a single conclusion. Reality must be like this and not like that. It's how we have been able to establish what kinds of forces operate on atoms and develop mathematical descriptions of the resulting behaviour. Atoms are predictable. There's no question but that atoms exist at the energy levels relevant to human existence. Of course, we know that atoms are made up of smaller entities and, as Sean Carroll says, the whole of reality is more accurately conceived of as interacting fields. But the fact remains that if there were another force acting on atoms we'd see it and we don't see anything that is not attributable to the known forces: gravity, electromagnetism and the two nuclear forces. If there is a supernatural force, then it is too weak to have any effect.

Even the most ardent Dualist must admit that our maps are pretty good. We can now manipulate individual atoms and even their smaller constituents to create computers, communications networks, GPS satellite networks, vaccines, and all that kind of stuff, based on our maps. The maps are accurate beyond the perception of any person.

Similarly, by comparing how different people experience the same object, for a large number of objects, we can tell what the mind is like. This is what neuroscientists have begun to do. So, in fact, we have a pretty good idea of what reality is like, and we're beginning to understand how the mind works (with a lot of information coming from how the mind breaks down; cf First Person Perspective).

3.2 It's Just a Theory

Another counter-argument is the "It's Just a Theory" argument. It is true that we cannot absolutely prove these scientific theories, as Sean Carroll himself has written about (See his blog What I Believe But Cannot Prove). In an absolute sense we cannot prove anything, and this leads some people to conclude that no certain knowledge is possible. Relativism of this kind ought to undermine all explanations equally and yet, somehow, it does not. Somehow, it is treated as a justification for dualism or mysticism. Taken literally, no certain knowledge means no knowledge at all. No assertions of fact can ever be valid. This seems like an unproductive stance to take. Arguing "I know that there can be no knowledge" is a tautology.

A scientific theory is a not "just a theory" in the sense that any old theory can be substituted and work just as well. In order to be accepted as a scientific theory, an explanation must explain relevant observations. Carroll uses the example of Einstein's General Relativity proposed a century ago this year. Not only did it explain an existing problem, the precession of the perihelion of the orbit of mercury, but it made a series of new predictions that could be tested (Wikipedia has a list of these predictions). For example, General Relativity predicted that light travelling close to masses would follow a curved path because masses curve space-time. This was confirmed by observing stars during a solar eclipse in 1919. Subsequently General Relativity has survived every test. To the limits of experimental accuracy General Relativity predicts the behaviour of matter and energy on large scales. For example, our GPS satellites would not work if we did not factor in relativity because time passes quicker for satellites in orbit than it does for people on the ground because masses slow down time! Far from being 'just a theory', General Relativity is a theory that has withstood intense testing and scrutiny to the point that there is no reasonable doubt about it. If non-believers can think of a new test that will prove General Relativity wrong then they are welcome to try. Fame and Nobel prizes await the person who succeeds. (See also the video 'Why Science is NOT Just a Theory').

The hypothetical possibility that a theory might be disproved does not invalidate the theory. At some point the theory of General Relativity must be reframed in such a way as to marry it with quantum mechanics (though Stephen Hawking has said he doubts this will ever happen), but the chances are that General Relativity will not be invalidated by this; it will simply become a special case of a more comprehensive theory. Carroll says of his view of the universe:
" would be unreasonable for me to doubt it; those beliefs add significantly to my understanding of the universe, accord with massive piles of evidence, and contribute substantially to the coherence of my overall worldview."
And just to repeat,
" the energy, mass and length scales relevant to your everyday lives" we know all the laws of physics... "If there are any other forces, particles, fields or phenomena they can't affect the atoms in your brain and body because either they are so weak that they could not affect the atoms, or we would have found them. Those are the only two options." 
There is no reasonable doubt that we know everything we need to know about atoms to rule out the afterlife. Which brings us to statement four.

4. When you die there is no way for the information that was you to persist
“The law that entropy always increases, holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations—then so much the worse for Maxwell's equations. If it is found to be contradicted by observation—well, these experimentalists do bungle things, sometimes. But if your theory is found to be against the second law of thermodynamics, I can give you no hope; there is nothing for it but to collapse in deepest humiliation.” — Sir Arthur Eddington (The Nature of the Physical World, 1915)
If propositions 1-3 are true, and to the best of our knowledge they do seem to be, then everything we are depends on the arrangement of atoms in our bodies. Everything. Indeed, we know that if we start to disorder those atoms, especially in the brain, then we begin to lose parts of ourselves. One of the most poignant examples is dementia. As parts of the brain are damaged or replaced by scar tissue, memories fade, the personality is distorted and the intellect fails. The person we knew gradually fades from view, until they are gone quite a while before the body dies. No form of death is pleasant, but watching a person die slowly this way is especially painful. There's no question, but that the destruction of the brain leads to the destruction of the mind. If the mind were not the brain we would not expect the devastation of dementia to be so complete. It would not matter if the brain was destroyed because the mind is not the brain. But this is what we see: destroy the brain, destroy the mind.

Here, again, there are exceptions. The brain is extraordinarily plastic. So people who suffer from hydrocephalus, for example, can end up with a brain volume of about 10% of average and still function. It's not clear how this affects the number of neurons, and since humans have widely differing brain sizes but a very similar number of neurons, the volume issue is less interesting than it seems at first. A 5ft tall woman will have considerably less brain volume that a 7ft man, but may have considerably more intellectual capacity. Some epilepsy sufferers have had half their brain removed and continued to function. In this case, the part of the brain removed was diseased and not functioning anyway, so the loss of it was not as catastrophic as it might be for a healthy individual. Typically, this operation is an extreme reaction to one side of the brain producing almost constant seizures and the ending of seizures is a good trade off for any down-side of the radical excision of one side of the brain. Still, it is remarkable how the brain adapts.

The main reason that the information that makes up 'me' is lost in death relates to the Second Law of Thermodynamics, which says that in any closed system entropy increases. If we add milk to coffee, they mix spontaneously and form an homogeneous mixture. Unmixing the mixed milk and coffee is more or less impossible. A living being takes in low entropy energy and excretes high entropy energy, thereby allowing it to maintain the order of its atoms that might otherwise tend to become disordered. When we die this process stops and our atoms quite quickly become disordered and the information stored as ordered atoms that constitutes "us" is lost. Five minutes of not breathing and the disorder is irreversible.

And, because there are no significant gaps in the physics, there is nowhere for something that survives the destruction of the brain to hide. There's nothing extra to survive your death; there's no way for your consciousness or your karma to be transmitted to another brain. There's just no room for that to happen. For Buddhists, this argument is especially salient. The history of Buddhist ideas is dominated by the problem of continuity: too much and it starts to look like a soul, too little and karma cannot work. Different sects push the boundaries in both directions, almost always attracting derision from their fellow religionists. Physics, it turns out, says that beyond any reasonable doubt there is and can be no personal post-mortem continuity. If we are relying on a God of the Gaps argument for consciousness, we just ran out of gaps for the mind or the spirit to hide in.

It's game over for the afterlife and we have to start rethinking religion. Really. It's time to start over. Sean Carroll, speaking specifically to the conclusions people draw from near death experiences, puts it like this: 
"There are only two choices: some ill-defined metaphysical substance, not subject to the known laws of physics, interacts with the atoms of our brains in ways that have thus far eluded every controlled experience ever performed in the history of science, or, people hallucinate when they're nearly dead."
And yet some people, presently the majority of Buddhists, think option one sounds better. The idea that our special experiences might not be precious insights into the nature of reality, but something far more mundane does not appeal to the religious. And this is understandable. 

If I say that the light I "saw" and the voice I "heard" were a manifestation of White Tārā (to use an example from my own life) then I get a certain amount of kudos from my peers. Visions are seen as important confirmations of religious faith and articles of that faith. The vision is vouchsafed to the devotee who is pure of heart, so those who have visions are held in high regard. If I am embedded in a religious context, then my vision reinforces my status in the group and my own faith in the tenets of the group. On the other hand, if I deny the validity of the vision I am placing myself in opposition to the will of the group which will make them hostile to me. Either the group will try to coerce me into compliance or it will shun me (at worst kill me). There is a small chance that I will influence the will of the group to change its view. In reality, my best hope is to provide ammo for more charismatic group members who have a better chance of swaying the collective will, by refining and extending the arguments we rely on to get a decision. Which is what I see myself doing.

Even some people who are well versed in the laws of physics (at least one colleague of mine has a Cambridge degree in physics) believe in an afterlife. Perhaps because the social cost of not believing is so high? Perhaps because an unfair universe seems unbearable? Perhaps they are just confused? I don't really know. Certainly, most people have only the vaguest grasp of science and can hardly be expected to base their beliefs on an understanding of physics. A patent example of this was a recent BBC radio documentary featuring novelist and "Professor of Contemporary Thought" at Brunel University, Will Self: Self orbits CERN. Self is famously well versed in the English language and specialises in use of obscure and archaic words. He has a huge vocabulary. But he is so hopelessly lost when confronted by the scientists involved in the CERN project that he confesses that he does not believe that they can be doing what they say they are. He literally does not believe in the Large Hadron Collider. If one of Britain's leading intellectuals is so hopelessly lost, then what hope for the average person?

Honouring the Experience

One of the qualities which has marked our Thomas Metzinger for me is the inclusiveness of his vision (something Sean Carroll lacks). Metzinger has said that a theory of consciousness which did not account for out-of-body experiences is just not interesting. The scientific study of consciousness is still relatively young. When James Crick joined the Salk Institute in 1976, less than forty years ago, the field was just getting started and was hardly taken seriously. It is understandable that scientists would want to start with the basics, to try to understand the generalities. Perhaps they can be forgiven for putting the mystical and the weird to one side to begin with. On the other hand, secularists are often a bit dismissive of unusual experiences, though I think this is slowly changing. Studies of meditators meditating are currently quite popular, and the surge in interest in using mindfulness techniques for health and wellbeing are helping to fuel this. It may not last, but I think the frontiers of human experience are likely to become more interesting to scientists as they bed down the basics. Scientists like Olaf Blanke are studying the once inaccessible out-of-body experiences and can now routinely induce them in subjects. What they learn extends our understanding of the mind.

Even when challenging the interpretation of such experiences, it's important to acknowledge that, for the person having the experience, it can be very significant. In seeking a different explanation, we might inevitably create tensions. Demystifying or de-romanticising experience is likely to be painful for the mystic or romantic. We do need to be sensitive to this. Attacking someone's beliefs with no regard for how that person feels is unethical. I know that other essays I've written on this subject have upset people. I don't aim to upset anyone, I aim to convey my understanding of what's going on (though I am susceptible to various human flaws).

In seeking to understand, we can draw two kinds of conclusions: what knowledge tells us about the world, and what it tells us about the mind. We already know that it's possible to fool the mind. Just look at optical illusions, let alone hallucinations. We need to allow for this in our calculations. It may be that a certain type of experience, say oceanic boundary loss, cannot be interpreted literally. We are not literally one with the universe. We do not leave our body during an out-of-body experience. However, that kind of experience can legitimately change the way we relate to the world, and especially to the people in it. The feeling of being 'one with everything' can break down artificial barriers between people. Imagine if we all had the experience and could all relate to the other more easily and positively? It's an optimistic vision. It inspired a lot of people in the 1960s even if their route in was via LSD. Altered states of consciousness alert us to new possibilities. They remind us that the brain is flexible. Such experiences are inherently interesting, even if we don't buy into ancient explanations of them.

It ought to be possible to hold both the underlying explanation and the philosophical conclusions. And if there is some tension, then it is likely to be a creative tension. That said, I know many Buddhists would like to cast me out of the Buddhist community for even expressing these views. One of the most senior members of the Triratna Order is insistent that one cannot be a Buddhist if one does not believe in rebirth (fortunately others are more of my mind). This is a widespread view. But if the afterlife is not true, then Buddhists have no choice but to change their minds and their spiel. It's difficult to admit we got it wrong after so many centuries, but if we truly believe that everything changes, then embracing this change ought to be possible.

The Afterlife is a False Consolation

The afterlife most familiar to most scientists in the West is Abrahamic: one dies and goes to heaven to meet God and live forever (only infidels go to hell). Carroll inveighs against this version of the afterlife. However, the points he makes are relevant to the Buddhist afterlife. We sometimes forget that the appropriate comparison is not heaven = saṃsāra, but heaven = nirvāṇa (a point that was clearly not lost on the early Buddhists who used this comparison on a number of occasions). The main point is that there cannot be a perfect state of being in reality. Perfection denies the physics of life which is all about change. Perfection is a state of zero change and thus perfection is the opposite of life. Perfection requires an alternate reality, i.e., heaven or nirvāṇa, but nothing could live in that reality.

Perfection is not even a desirable state. In fact, living forever would be unbearable, even if our every whim were granted, because getting what we desire is never ultimately satisfying (desire simply shifts to a new object). The Upaniṣads and early Buddhist texts highlight an alternative idea to satisfying all desires, which is to be perfectly free of desire. But this is not possible for the living either, and can only find completion in death. Sean Carroll goes further and warns against fetishing happiness. When we make happiness our goal we tend to end up on the hedonic treadmill. This is because we associated happiness with pleasure or satisfying desires. And desires, as above, can never be ultimately satisfied.

In other words, this godless, reductionist, materialist has adduced two of the main points of Buddhism as important principles for living, and presents them without any super-natural super-structure. It shows that we can be moral, and even wise, without the burden of traditional religious beliefs.

The end of the afterlife is a bitter pill for Buddhists, because it means that our traditional narratives of karma and rebirth are over. If I say "Karma is dead" it is of the same order as Nietzsche's pronouncement "God is dead". Without the afterlife, karma cannot ensure the fairness of the universe. Many people come to Buddhism because of an experience of unfairness (illness, death, divorce, etc.). And they are attracted to the idea that things balance out. But, unfortunately, we have to let this idea go. And experience suggests that Buddhists can be quite hostile to this suggestion.

The end of the Myth of the Afterlife is a beautiful moment for humans. We are growing up. We are finally seeing things as they really are. We have to deal with things now. We are responsible for what is happening. It means the onus is on humans to both reward and punish more assiduously, and to think very carefully about what constitutes good and evil, because the universe is not going to square things up after death. The universe is ordered, but it is not a moral order. It means that if we want to have meaningful lives we have to put the meaning into life ourselves; and not expect to find it in death.

It's a new world.


25 March 2015
"At the root of the muddle [about consciousness] lies an inability to overcome the Very Large Mistake so clearly identified by Eddington and others in the 1920s—not to mention the lovely Irishman John Toland in 1704, Anthony Collins in 1707, Hume in 1739, Priestley in 1777–8, and many others. The mistake is to think we know enough about the nature of  physical reality to have any good reason to think that consciousness can’t be physical. It seems to be stamped so deeply in us, by our everyday experience of matter as lumpen  stuff, that not even appreciation of the extraordinary facts of current physics can weaken its hold." - Galen Strawson. 'The consciousness myth (revised).' The Times Literary Supplement 27 February 2015 (no. 5839 pp. 14–15)

18 July 2014

Buddhism and the Observer Effect in Quantum Mechanics

This essay is a follow up to one I wrote in 2010 called Erwin Schrödinger Didn't Have a Cat. It might be worth refreshing your memory of that one first. Plus I've continued to add notes since writing the original article.  The subject of Buddhism and quantum mechanics keeps coming up. Quantum mechanics seems to draw Buddhists like moths to a flame. Of particular interest seems to be the observer effect that Schrödinger used to critique the Copenhagen interpretation. Google "Buddhism Quantum Mechanics and the Observer Effect" and you'll get a raft of webpages talking about how observers interact with the physical world.  They say things like:
"Basically, what quantum theory says is that fundamental particles are empty of inherent existence and exist in an undefined state of potentialities. They have no inherent existence from their own side and do not become 'real' until a mind interacts with them and gives them meaning. Whenever and wherever there is no mind there is no meaning and no reality. This is a similar conclusion to the Mahayana Buddhist teachings on sunyata." Buddhism and Quantum Physics.
This is not quantum mechanics or Buddhism either. It's Idealism combined with the strong form of the anthropic principle. It's very misleading. Buddhism is talking about mental events and quantum mechanics about subatomic particles. At best the relationship is metaphorical, because subatomic particles don't behave like mental states and vice versa! In this blog post I will explore what the observer effect is and why it has very little or nothing to do with consciousness and also why it does not support Idealism.

I have to confess there is a great deal that I don't understand about quantum mechanics, not least of which is the maths involved. No one likes to admit they are ignorant, but I know that I don't understand this stuff to any great degree. I know that most of the Buddhists writing about it don't understand it either. I just wish they'd admit it.


Mass of the electron

In this essay I'll focus on the electron. Electrons have reasonably well defined properties and are all, so far as we can tell, identical. For example electrons have mass of approximately 9.10938291 × 10-31 kilograms. This is literally an unimaginably small number. As far as the human imagination is concerned this is zero. Protons have almost 2,000 times more mass than electrons and that's still an unimaginably small amount. Clearly there is some measurement uncertainty in this figure, we can only measure it as accurately as our experimental design and measurement device allow, but it's precise to an extremely fine degree. Similarly, electrons have an electric charge of approximately −1.602×10−19 coulombs, or a billionth of a billionth of the current that comes out of your wall socket.

Most relevant to our topic, an electron has an intrinsic angular momentum of either +½ or -½. Electrons seem to behave as though they spin on their axis, though in fact there is no classical phenomenon which the "spin" of an electron is exactly like. Seen from above the angular momentum of a clockwise spinning top points up, and for an anticlockwise spin it points down. So conventionally we speak of spin up and spin down.

Classical objects (roughly speaking, objects perceptible by our unaided senses) obey the classical laws of physics. A spinning top is a classical object. As it spins it has momentum: it will keep moving unless a force acts on it. Since it experiences friction as it spins it gradually and smoothly slows down, shedding kinetic energy as heat and sound. Even the solar system is gradually slowing down, the rotation of the earth is gradually slowing down. However, an electron just 'spins'. Always. Without ever slowing down. I presume that even at absolute zero, an electron has spin.  Additionally, though a spinning top tends to orient itself, the axis of spin need not be in any particular direction, and can even wobble around. So the 'spin' of an electron here is a metaphor for an incomprehensible underlying reality.

Curiously if you rotate an electron with spin ½ through 360° then you would expect that the angular momentum would be the same, but it is in fact -½. To get back to spin ½ we have to rotate the electron through a total of 720°. Again there is no physical analogy that can explain this, no real process to compare it to. And this is partly why the great genius Paul Dirac said: "The fundamental laws of nature control a substratum of which we cannot form a mental picture without introducing irrelevancies." (Principles of Quantum Mechanics. 4th Ed. 1958).

If a spinning top had an electrical charge it would generate a magnetic field. This is more or less how an electric engine or generator works. Moving electric charges produce magnetic fields and moving magnetic fields induce electric currents. Electrons, having an electric charge do produce a magnetic field as they 'spin'. However looking at the electron as a classical spinning object with electric charge causes some problems. It turns out that in order to generate the measured magnetic field an object the size of an electron, considered as a classical object, would have to spin so fast that a point on its surface would be going several times faster than the speed of light. And the answer to the problem in fact turns out to be that the electron does not seem to have a size. This is deeply counter-intuitive. To have mass but no size suggests infinite density. I'm not even sure how the physicists deal with this problem.

We're starting to see that a single electron does not obey the classical mechanics (aka the "laws of physics") and this is where quantum mechanics comes in. Quantum mechanics is a series of equations which describe the behaviour of sub-atomic particles, like the electron. They were the first physical laws to be derived theoretically rather than through observation, but on the whole they do describe the behaviour of sub-atomic particles (though there are still competitors waiting in the wings - see article on bouncing oil drops at the end of the essay). 

In the quantum world there are restrictions on everything: every quantity is a multiple of some constant with no in-between values (hence quantum). Transitioning between quantum states is instantaneous and discontinuous. For an electron there are just two possible spin states (i.e. two states of angular momentum): spin up and spin down. An electron can be made to flip states, but the action is instantaneous with no transition and no in-between states. Something one never observes in the macro world. 

In my description of water I noted that electrons move around an atomic nucleus in well defined orbitals or shells. In hydrogen for example the single electron occupies the s shell which is spherical. Helium has two electrons in the s shell. Now Linus Pauli discovered that if two electrons are in the same orbital then they must have opposite spin (called the Pauli Exclusion Principle). The next shell, p, can accommodate 8 electrons, but they in fact occupy four separate orbits that each accommodate 2 electrons of opposite spin.


This quality of spin is an important one because it was this quality that Schrödinger was referring to in his famous thought experiment. A consequence, an unbelievable consequence from Schrödinger's point of view, of the Copenhagen interpretation of quantum mechanics was that an electron could be either spin up or spin down and we wouldn't know which until we measured its angular momentum. Niels Bohr argued that before being measured the spin state would effectively be a super-position of both states. Schrödinger's example of the cat was intended to show that the conclusion was untenable because the idea of an object being in two states at once was ridiculous. As it happens the Copenhagen Interpretation won the argument and now advocates use Schrödinger's complaint to illustrate the point about super-position.

It's the spookiness of this metaphor that seems to attract Buddhists. They latched onto this idea of the necessity for the "observer" to break the symmetry of superposition and force the electron to take up one spin state or the other, because it looked like the Idealist end of the Yogacāra spectrum of thought in which objects are brought into existence by an observing mind. That Yogacāra is inherently Idealistic is hotly disputed by scholars, but for many Buddhists what cittamātra means is that only mind exists and as one Idealist Buddhist put it to me recently:
"I agree with Schopenhauer - objects only exist for subjects. Without a subject who brings to the picture, a sense of relatedness, some proportion, a point of view, there are no objects whatever." (
Tying Buddhist Idealism into Western Idealism is a popular pastime amongst Western Buddhists and Schopenhauer is a favourite exponent of this kind of thing. But just because a 19th century philosopher thought this or that about the universe tells us nothing. The fatal flaw is that this kind of Idealistic ontology has no possible supporting epistemology - there's no way to gain this knowledge about the nature of objects from a Buddhist point of view. In this view we have no way to know what happens to objects when we stop observing them, because we are not observing them! It's simply a theological position. And as I said in the post on ineffability we can easily infer that it's not true simply by comparing notes. Those who fail to compare notes come to ridiculous conclusions that are hard to shift. One of the logical consequences of this anthropocentric Idealism, a variant of the Anthropic Principle, is the the entire universe goes out of existence and then comes back into existence when we blink our eyes. And if you believe that you'll believe anything.

There's rub...

Part of the problem with employing the words of science without understanding them is that one makes silly mistakes. So for example when we say the mind of the observer is involved in determining the physical state of the electron, this is simply a mistaken understanding of what is meant by "observer". No electron has ever been seen by a human being. We need to be very careful about what we mean by "observe" and "observer". As physicist Sean Carroll says re "the observer":
"It doesn't need to be a 'conscious' observer or anything else that might get Deepak Chopra excited; we just mean a macroscopic measuring apparatus. It could be a living person, but it could just as well be a video camera or even the air in a room." [Emphasis added]
Schrödinger's observer, like Schrödinger's cat, is a metaphor. Given that no one can actually see an electron and 'spin' is only a notional quality with no classical analogue, how would we go about measuring the spin-state of an electron, one way or the other? Remembering that a single electron takes up more or less no space and weighs as close to nothing as makes hardly any difference. Usually we deal with electrons in amounts like billions of trillions and in such numbers they collectively behave classically. It is possible to assemble a set up that will shoot out one electron in a known direction every so often, but they travel near the speed of light. If your detector is 1m away from the emitter then it takes about a billionth of a second to get there. And since they're all identical there's no way to find our electron afterwards. So good luck observing an electron with your senses and comprehending it in your mind!

Actually it is possible to trap individual electrons, but as I think will be clear, the interaction needed to so do, involving magnetic fields, make them useless for testing the observer effect. However, thankfully it's not very difficult to measure spin-states in practice. We just need to construct a macroscopic measuring apparatus known as the Stern-Gerlach experiment

In the Stern-Gerlach experiment a beam of electrons is passed between two magnets like those shown right (we'll ignore the shapes). The path of electrons with spin up is bent up as they pass through the magnets, electrons with spin down will bend down. So we then know the spin of the electron. We can measure the numbers that are bent each way by using an electron detector. And what we find is two very small spots - the up-spin electrons all hit the same upper spot, and the down-spin electrons all hit the same lower spot. There are never any in-between and any blur we see is due to fluctuations in the experimental set up itself, not in the electrons. At this level of sensitivity the tiny fluctuations caused by Brownian motion become noisy enough to drown out any signal. The amount by which the electron is deflected is related to it's mass and magnetic moment. 

Now assuming we can use this to measure the spin of individual electrons what is going on here? An electron leaves the emitter and travels for a billionth of a second in an indeterminate spin state before passing through the apparatus and hitting a detector. An electron detector might be a loop of wire with an ammeter on it. As the electron hits the wire a very small, but measurable current flows (this is more or less how an old-fashioned vacuum tube works). Or we use a device like a TV screen that emits light when hit by a fast-moving electron and a photo-detector to record the light. As an electron travels through the apparatus and interacts with the magnetic field, it takes one or the other spin-state and enters one or other detector. It's the interaction of the electron with the experiment, with the macroscopic measuring apparatus, that forces it to adopt one or other spin and it does so at random.

And where in all of this is the "mind of the observer"? In fact the "observer" here, the experimental apparatus, has no mind. Why do we think of a person observing things and influencing them? It's because we understand Schrödinger's metaphor (man watching box) but we have no idea what underlying reality is being described. But this is a dangerous illusion.

The mistake that almost every Buddhist makes is to assume that because they understand the metaphor of Schrödinger's cat, they understand the underlying reality. This problem pervades Buddhist thinking. In the case of quantum mechanics no one understand the underlying reality, not even the people who understand the fiendish maths that predict the behaviour of particles. The reality of the quantum world is literally unimaginable, even when the theories make accurate predictions.

In fact when scientists talk about "observing" a subatomic particle (something with unimaginably small vital statistics) they really mean causing it to interact with something in a way that can be amplified and signal to us humans, on a scale we can comprehend, that something or other has happened. So all this stuff about consciousness and the observer effect in quantum mechanics is bunk. It's based on a reified metaphor and a false analogy.

The false analogy is with the observer effect in anthropology. When an anthropologist studies a culture they cannot help but see through cultural lenses. And they also change the behaviour of the people they study by being there. Famously teenage Samoan girls told Margaret Mead a bunch of lies about their sexual habits which for them was a huge joke, but wrecked the anthropologist's reputation. (Her work was debunked by Derek Freeman after she died, though his book Margaret Mead and Samoa set off a heated debate in the field of anthropology). Another variation on this is seen in the Hawthorne Effect which describes how workers modify their behaviour in response to conditions, especially whether or not they are being observed by management.

Observing humans does
change their behaviour.

There is also some contamination from post-modern literary criticism which emphasised the role of the reader in the "creation" of the text and called into question the very possibility of objectivity. Amongst the influential (if indirect) contributions to this discourse was Edward Said's work on so-called Orientalism which sought to show that Western views of Asia were constructs that were often only loosely related to Asia itself and were more revealing of the prejudices of Western scholars than of Asian culture and custom. At the same time the very idea of objectivity was called into question in the sciences, though this critique consistently failed to take into account the collective nature of scientific enquiry. The metaphors of quantum mechanics were conflated with these other issues and for many poorly informed people came to represent the nature of the problem of objectivity and subjectivity.

Quantum Nonsense.

Buddhists who know a little about quantum mechanics and a little bit about litcrit or anthropology are apt to fall into error. The temptation is to think that because we understand one or two metaphors or allegories that we understand the whole field. Almost no one does. Richard Feynman, another genius, was more bold:
"I think I can safely say that nobody understands quantum mechanics." (The Character of Physical Law, 1965). 
And if he didn't understand it, then probably no one could. The map is not the territory. And we Buddhists are not even using quality topographical maps. We're mostly using the cheesy, massively oversimplified, tourist maps that are given away for free in Hotel lobbies, all covered in advertising.

Too many Buddhists see in quantum mechanics a confirmation of their Idealism: the idea that there is no reality independent of the observer. I hope I've shown that such claims have misunderstood the word "observer" in Schrödinger's complaint. The conclusion drawn from quantum theory by many Buddhists, that the world only exists as and when we perceive it, is simply wrong. Indeed one of the consequences of quantum mechanics is that there must be an observer independent reality. (See Sheldon Goldstein, Department of Mathematics, Rutgers University: Quantum Theory Without Observers; and also links below).

This problem pervades Buddhist doctrine. It is full of empty metaphors. Karma is described almost entirely of such empty metaphors for example. However unlike in physics, Buddhist metaphors are not linked to mathematical models that make accurate predictions. Karma is linked to moral theories that are intended to ensure compliance with Buddhist behavioural norms. In other words Buddhist metaphors are set to prescriptive purposes, whereas physics metaphors attempt to be descriptive. This is a fundamental different between religion and science. 

I doubt quantum-nonsense will ever go away. Too many people are desperate to consume what purveyors of quantum-nonsense are selling and not equipped to make a good judgement, or unwise in whose judgements they rely on. If our teachers are also non-scientists hungry for some quantum-nonsense too, then we are in deep trouble. Buddhists have the unfortunate habit of seeking and finding confirmation of their views everywhere they look. The most trivial or banal coincidence of wording becomes a hidden "Dharma teaching". Buddhists Tweeters endlessly repeat platitudes as though they were profound. Buddhist bloggers give over inordinate amounts of space to celebrity Buddhists as though having someone famous adopt Buddhism makes the world a better place. It's all so tedious. Next thing you know we'll be knocking on doors asking people if they have accepted the Buddha into their lives.

The fact is that science is not proving what Buddhists have known all along. It is doing the opposite. Science is tearing apart the articles of faith of Buddhism;  leaving karma, rebirth, heaven & hell, and dependent arising as a Theory of Everything, in tatters. It's only blind faith and massive bias that prevents people from seeing this. We have a lot of work to do if Buddhism is going to survive this collision with modernity. Presuming of course that we do not fall back into another dark age, and looking at nominally Buddhist countries like Tibet, Korea, Burma, Sri Lanka and Thailand that possibility seems all too likely.


Some real Quantum Physics:

Extra Notes

21 June 2015
Nature has just published a new article with an argument about why large scale objects do not exhibit quantum indeterminacy, How Gravity Kills Schrödinger's Cat (Nature, 17 June 2015). Confirming my reading of the observer affect the author says "As soon as a quantum object interacts with a stray particle or a passing field, it picks just one state, collapsing into our classical, everyday view." The "observer" is in fact any physical interaction. And fields pervade the universe! Macro-scale objects interact with the gravitational field:
"Because of gravity’s effect on space-time, Pikovski’s team realised that variance in a molecule’s position will also influence its internal energy — the vibrations of particles within the molecule, which evolve over time. If a molecule were put in a quantum superposition of two places, the correlation between position and internal energy would soon cause the duality to 'decohere' to the molecule taking just one path, they suggest."

11 Oct 2017
I went to hear Professor Philip Moriarty last night and he made an interesting point about Schrödinger's cat and the "observer". He reiterated the point that I have tried to make here, which is that "the observer" is any physical interaction with matter. The cat interacts with the matter in the box, which collapses the wave function. Therefore the super-position collapses into a definite state long before we look into the box. In fact from our point of view, the cat is never really in a state of superposition, because there is no point at which it is not interacting with matter in such as way as to collapse the wave function. I understood Professor Moriarty to say that as an experimental physicists (he images single atoms and molecules in his day job) he believes that there is no empirical evidence that would make one interpretation of quantum mechanics more likely than the others.