Some time ago (five years, actually!) I wrote an article about reincarnation, followed by a video of me reading the article. I thought, and still do think, that it went some ways towards explaining the idea of rebirth according to Buddhist principles. One thing I realize now, though, is that it didn't go very far towards answering the repeated call for proof of past lives and rebirth, something I would like to attempt now, in this article.
First of all, let us do away with the (maybe semantic) mistake of looking for actual proof at all; modern science doesn't deal in proof, and so there is no reason for a modern scientific mind to expect proof of anything, including rebirth. What modern science does expect is theories that are consistent with all of the facts and contradicted by none. It is commonly understood in science that a single example of inconsistency or contradiction is all it takes to disprove a given theory, no matter how many consistencies and accordances to reality it may otherwise claim.
Classical Newtonian physics is a good example of this principle. Before the advent of quantum physics, it is was generally assumed that the physical world behaved in a mechanistic, predictable manner, based on a simple set of laws of cause and effect that allowed for complete determinism in the physical realm. In the early 1900s, however, certain observations were made in regards to the behaviour of physical matter that contradicted classical physics and caused it to be discarded in favour of quantum mechanics (more on this later). Even though classical physics was and is still very much in accordance with ordinary experience and observation, once it was found to conflict with a single observable event, it had to be discarded in favour of a theory in harmony with that event.
Moreover, science requires adherence to the principle of "lex parsimoniae" (a.k.a. Occam's razor) which is to "select from among competing hypotheses that which makes the fewest assumptions " (Wikipedia). For example, it may be harmonious with all observations to postulate an omnipotent creator god (whose omnipotence can conveniently explain away any inconsistency), but it is certainly not the most parsimonious theory we might choose.
These two principles, harmony and parsimony are what we should look for in any scientific theory, not proof.
Unfortunately, things are not so simple as might be implied by the above explanation. Before we can say that something accords with reality in the most economical way possible, or accords with reality at all, we must be able to define reality. This, I think, is the most poorly appreciated truth among the modern scientific community, that a theory in which claims about reality are made requires a preconceived notion of what reality is in the first place.
The reason for this lack of appreciation, I think, is an understandable disdain for allowing philosophy to enter into scientific discussion. Nonetheless, it seems impossible to avoid its inclusion, for the very reason that much modern scientific theory requires the acceptance of a corresponding philosophical theory that has a tenuous relationship with reality at best, that of observer-independent existence.
Modern scientific theory is still broadly based on the idea that the physical universe “exists” independent of any observer, subject to strict deterministic laws that allow for absolutely predictable results, given enough data about the state of the universe before a given event.
This idea was actually shown to be false almost 100 years ago with the advent of quantum mechanics, which allowed for uncertainty to enter into the system and, moreover, required an observer as a precondition to any discussion of physical entities whatsoever, removing the need to postulate an independently-existent substratum of four-dimensional space-time. What orthodox quantum theory (i) did, in essence, was remove the any preconception about the nature of reality whatsoever from the field of scientific inquiry, strictly limiting the focus to descriptions of observations, rather than entities. As Neils Bohr put it:
“In our description of nature the purpose is not to disclose the real essence of phenomena but only to track down as far as possible relations between the multifold aspects of our experience.”
Or Werner Heisenberg:
“The conception of the objective reality of the elementary particles has thus evaporated not into the cloud of some obscure new reality concept but into the transparent clarity of a mathematics that represents no longer the behavior of the particles but rather our knowledge of this behavior.”
The reason for this circumscription of the extent to which science can explain reality was, on the one hand, simply an admission of inability, rather than denial of the existence of something more. In other words, orthodox quantum mechanics didn't necessarily refute the existence of a deterministic, impersonal universe, it simply pointed out the necessary limits of science in describing such a universe.
Nonetheless, many theories have since arisen to renew the quest for an impersonal, entity-based, deterministic explanation of reality (the many-worlds theory, for example). The point I would like to make in this paper is that there is no reason to suppose the existence of an impersonal, deterministic reality in the first place; such a supposition is not in the realm of science, but squarely a question for philosophers and, as such, not susceptible to scientific enquiry.
Such is the beauty I find in orthodox quantum theory. The quotes of Bohr and Heisenberg encapsulate for me what is meant by both scientific and Buddhist enquiry into the nature of reality. By refusing to address questions of determinism and impersonal physical reality, it has met both of our requirements for scientific acceptability – it is perfectly consistent with observation and parsimonious to an extreme; and from a Buddhist perspective, it fits neatly with a phenomenological view of reality like that of the Buddha himself.
The greatest objection to orthodox quantum theory, I think, is that it fails to provide a Cartesian-type model of the universe. To me, that is the beauty of it. Instead of attempting to answer the philosophical question of whether something exists or not, it proceeds to accurately describe and predict observations about whatever it is that does, in whatever form, exist.
That this paradigm shift met with great resistance (even from Einstein himself) is a testament to how difficult reality is to understand. Schrödinger's Cat, a well-known example of how Quantum Theory cannot be directly applied to an observer-independent physical universe, shows this difficulty and, I think helps one to make the required paradigm shift, both for understanding Quantum Physics and for understanding Buddhist theory as well.
What is Schrödinger's Cat? In the words of Schrödinger himself,
One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter, there is a tiny bit of radioactive substance, so small that perhaps in the course of the hour, one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges, and through a relay releases a hammer that shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts. It is typical of these cases that an indeterminacy originally restricted to the atomic domain becomes transformed into macroscopic indeterminacy, which can then be resolved by direct observation. That prevents us from so naively accepting as valid a "blurred model" for representing reality. In itself, it would not embody anything unclear or contradictory. There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks.
Okay, so maybe that's not crystal clear to us non-scientists, but we should at least be able to understand that he means to say that orthodox quantum theory, dependent on an observer to function, cannot be thought to describe observer-independent space-time. Why? I can't give the quantum mechanics explanation (basically it's because one simply cannot describe such a reality in scientific terms, without introducing unwarranted complexity - e.g. many-worlds theory, or talking about living-and-dead cats), so I'll give the Buddhist one: because there is no proof that such an observer-independent substratum exists, nor is it the realm of scientific enquiry to prove (or disprove) that it does.
What I hope comes from this explanation is a bit of understanding that reality, far from being a concrete set of entities functioning in a deterministic fashion, is rather a description of experience which cannot by its very nature admit of the discovery of a concrete anything. As soon as we attempt to define fixed, predictable entities, we enter into the realm of philosophy, rather than science, and I think the issues pointed out by orthodox quantum physics are solid backing of this fact.
So, what does all this have to do with rebirth? Nothing and everything. The main point in my article about rebirth was that Buddhists don't really believe in rebirth, they just don't believe in death. In that article, I asked the reader to give up all of their philosophical preconceptions about reality and rely singly on objective observation. Under a strict scientific method, we find ourselves confined to describing observations of events, rather than the nature of events themselves. The event of death is a prime example of how this approach must inevitably change how we think about reality.
No one alive can claim to have ever experienced death. If we did postulate the existence of four-dimensional space-time, we could, based on the observation that physical organisms cease to function after a specific point in time, postulate the death of an conscious entity, concluding that from the moment of death onwards, the entity (defined as the organism itself) ceases to exist.
Yet in order to conclude that the conceptual death of an organism is the end of a being, one has to first prove that the being is equivalent to the organism. Moreover, one is obliged to prove that both the being and the organism actually exist, something that has already been argued as outside of the realm of scientific enquiry entirely.
Buddhist theory (and orthodox quantum theory) is under no such obligations. Rather than jumping to unwarranted conclusions involving the birth, life, or death of a being, Buddhism argues from first principles that objective observation shows a continued stream of experience to be the only verifiable framework for reality, and limits its discussion of reality to the nature of this set of observable phenomena.
Based on such observations, Buddhism postulates a causal order to reality based on the observed ability of one event to affect another (either concurrent or consecutive) event. For example, anger and greed have obvious effects on subsequent physical and mental states and experiences; so to does physical pain or pleasure, sense stimulation, memory recall, etc., all of which are verifiable without resorting to a physical or mental substratum-based theory of reality.
Viewed in this light, the concept of death is called seriously into question; since we cannot possibly observe the death of another stream of experience and would not be able to relate the death of our own, proponents of mental death are left with, at best, an appeal to external observations of the breakdown of physical systems that may or may not have anything to do with the continuation of experiential reality, with which to prove a theory that is in direct contradiction with the ordered causality observable in the system.
One of the ways that scientific thought progresses is by making educated guesses or predictions based on currently understood theories of reality that seem to satisfy the rigour of scientific enquiry. Einstein, for example, proposed three tests of general relativity, which served as predictions about how the theory would play out in observable reality. Not all of Einstein's predictions admitted of immediate verification, but eventually they were shown to be correct. The important point for our discussion, however, is simply that such predictions were made because they accorded with the theory – if the theory itself was correct, predictions based on the theory must also be correct.
So, one way of making the seeming leap between an experiential-based model of reality and the theory of rebirth is to predict what we would expect to find at the moment of physical death, based on observable experience. If our theory of observable experience is based solidly on the observations themselves, any predictions that are likewise solidly based on such a theory are, all other things being equal, likely to be correct.
True, there is nothing in observable experience to immediately warrant exclusion of the prediction of an end to causal experience at physical death, but there is equally nothing by which to recommend it. The most reasonable prediction would be one which postulates no change in the moment-to-moment reality of experience, since the readily-observable process of experience based on direct causal relationships exhibits nothing to indicate the likelihood of any such change.
Simply put, the burden of proof is on one who would postulate a direct relationship between physical and mental death, and such proof is entirely lacking. Nor does it matter that such a theory of mental death may be harmonious with observable reality; it, like theories of God and heaven, is to be discarded as introducing unwarranted complexity without proof, at least until such proof can be found and given.
Of course, it will be argued that physical death is a strong indication of some change of state in the mind, possibly even indicative of an end to mental experience entirely. The only way to prove such a claim, however, would be to establish and test the predictions of such a mental-death theory and show whether it were possible to invalidate such predictions with observations that contradict it.
It should be clear by now that I have, insofar as my argument is sound (which one is free to deny), completely turned the tables on one who would reject the concept of continuation of consciousness after death. There is no requirement of proof in regards to a theory that makes no unobserved claim about reality. Since experience is observed to exist before death, to say that experience continues after death is, in fact, to say nothing at all.
If it were only so simple, this paper might end there. Unfortunately for the weary reader, there is more to be said. Buddhist ontology admits of two modifications to a theory of uninterruptible experience, one which is readily observable and the other which is not.
The first modification is to allow for change (sometimes radical) in the stream of experience based on physical causes. It is clearly observable that certain events can and do have an effect on a person's experience of reality. An example that comes readily to mind is the effects of a stroke, exemplified by the well-known online video with Dr. Jill Taylor's recounting of her first-hand experience of how loss of brain activity drastically altered her experience of reality, though temporarily. Another example is experimental drug use, which can have both temporary and long-term effects on brain activity. So, apart from the process of physical death itself, we must reasonably admit the potential for change based on the observable outcome of such events as mentioned.
There is nothing in any of these examples (including that of physical death) to indicate an end to experience. Dr. Taylor's account of the stroke is very much in line with clinical studies of out-of-body experiences where even complete loss of brain function was shown incapable of negating conscious activity. A recent study of the drug Psilocybin showed that the heightened states of awareness caused by the drug were actually a result of reduced brain activity. And no matter how enticing it is to believe in the event of physical death as causing mental death as well, it is still just a belief, not backed up by any scientific observation.
The second modification is an admission that Buddhist ontology does admit of a single event capable of breaking the chain of causal experience – what is commonly known by its Sanskrit name, Nirvana. Nirvana in early Buddhist thought and practice is a state of cessation similar to what a materialist expects to find at physical death. A difference is that Nirvana is understood to be susceptible to temporary observation – meaning, a person who has seen Nirvana can live to tell about it. I offer this only as a qualification to the idea of a fundamentally unbreakable system of experience-based reality and leave it at that, since it is beyond the scope of this paper to discuss the phenomenon in depth (and since most Buddhists, let alone non-Buddhists, are not readily capable of observing it).
Apart from these objections, there seems little to prevent the development of a theory of continuation of experience after physical death, stating that one's actions and reactions are liable to, in the main, determine what follows, not the breakdown of any physical entity.
What this discussion has hopefully accomplished is to a) remove intellectual bias for a substratum-based ontology in which external entities dictate one's approach to the nature of reality, and b) show that the most parsimonious theory of what happens at physical death is one that, while admitting the possibility of mental alteration at the moment of physical death, favours continuation of previously observed mental activity over mental death.
If I have done my job thus far, the reader should have to admit there to be no reason for favouring equation of physical and mental deaths over their differentiation. Hopefully, the argument has inclined a favouritism for the latter but I would expect that to only be the case for ardent meditators who have had the opportunity to accustom themselves to an experiential approach to reality.
So far, nothing has been concluded beyond what the limited theory of Buddhist ontology (and, one might venture to suggest, orthodox quantum theory) should predict to occur at the moment of death. This in itself is significant, since, as stated, such a prediction requires no verification since it says nothing new. A theory of the equation of physical and mental death, however, does require proof, and here's where we go on the offensive.
In any scientific theory, proof lies only in how its predictions accord with actual observation; regardless of how reasonable or unreasonable a theory seems, it is to be accepted if and only if it fits the two criteria of harmony and parsimony. So, our final task is to discuss what is actually observed to occur at the moment of death. How could such a task be accomplished? I admit that at this point, we have to leave behind the security of facts, logic and theory in favour of clinical trial and observation, but I think not without benefit.
As I said, all we have to disprove mental death are clinical studies and anecdotes; cases of patients whose minds were active after their brains stopped, only to find themselves able to relate their experiences afterwards; cases of children who remember past lives, claims of monks and meditators who do the same.(ii) All of this is incredibly important since it must all be explained away by those who would adhere to a theory of equation of deaths, but it certainly is far from conclusive.
Nonetheless, it was never the intention of this paper to be conclusive. If you wish to verify beyond doubt whether life continues after death, you must experience it one way or another yourself. All I wished to point out is that there is no reason to prefer the theory of mental death over one based on continuation, and that in fact there is much reason to prefer the latter. Even if all of the "evidence" in favour of continuation of experience after physical death could be discounted as anecdotal or lacking in scientific rigour, an opposing theory would still be one solid observation away from dismissal.
Moreover, any contrary observation of mental death (beyond third-person observation of an absence of effluent, local activity at physical death) that might refute the theory of continuation after death is entirely lacking, though the absurdity of providing such observation seems to have been one reason for the theory's adoption by the scientific community.
Karl Popper said that a theory talks about observable reality only if it is falsifiable (i.e. capable of being disproved). Since the theory of mental continuation after physical death is thought to be unfalsifiable (since experience is thought to be undetectable), it is placed in the same category as God and eternal heaven. Physical death, on the other hand, being observable insofar as brain activity ceases, is considered to be sufficient evidence to conclude that the entity (being) has died.
There are two objections to this line of thinking, one of which has already been stated - that experience is in fact the basis on which reality is built, not physical entities, and therefore the burden of proof is on one who would claim the disruption of experience at the moment of physical death, not on one who would deny it. The other objection is that mental activity might very well be subject to observation. It might very well be possible that, just as physical instruments are capable of registering the presence or absence of brain activity, the registration of presence or absence of mental activity might be verifiable by similar mental means. The problem simply lies in an adherence to philosophical materialism (i.e. that physical entities are the basis for reality), not scientific principles or observations.
If one takes a materialist stance, one will be by definition incapable of including consciousness into the realm of scientific enquiry. Since a materialist claims that scientific observation must be confined to observer-independent registration of events by physical instruments, thus excluding consciousness from the start, it begs the question rather than providing a meaningful argument on subjects relating to mental experience; it also (as far as I understand) contradicts the tenets of orthodox quantum theory. If we allow that an individual experience carries some definite meaning, we can quite easily set up a hypothetical experiment whereby any number of scientists observe the death of another being.
This, by the way, is what the Buddha claimed to accomplish in the second watch of the night under the Bodhi tree:
When my concentrated mind was thus purified, bright, unblemished, rid of imperfection, malleable, wieldy, steady, and attained to imperturbability, I directed it to knowledge of the passing away and reappearance of beings. With the divine eye, which is purified and surpasses the human, I saw beings passing away and reappearing, inferior and superior, fair and ugly, fortunate and unfortunate. I understood how beings pass on according to their actions thus: ‘These worthy beings who were ill-conducted in body, speech, and mind, revilers of noble ones, wrong in their views, giving effect to wrong view in their actions, on the dissolution of the body, after death, have reappeared in a state of deprivation, in a bad destination, in perdition, even in hell; but these worthy beings who were well-conducted in body, speech, and mind, not revilers of noble ones, right in their views, giving effect to right view in their actions, on the dissolution of the body, after death, have reappeared in a good destination, even in the heavenly world.’ (MN 4)
right after he remembered his own past lives.
Anyone who claims, therefore that rebirth has no place in Buddhism is both misrepresenting the Buddha and misunderstanding reality - death is what has no place in Buddhism.
A final argument against continuation of mind after physical death, perhaps the most strongly adhered to, is the theoretical equation of mind and brain. I mention this only in passing, though maybe I should have included it earlier in the paper, since it rests directly in philosophical thought, not scientific enquiry.
I already pointed out that certain physical events can alter the mind's course in sometimes radical ways; it is the belief of many material scientists and lay people alike that neuroscience has more or less proven this relationship to the extent that the brain and mind must be equivalent. To show that it has done no such thing is beyond the scope of this paper (iii) but even if the clinical evidence were overwhelmingly suggestive of such a conclusion (which, I am confident, it is not), such an equivalence makes little sense on a theoretical level, when we are unable from the first to prove the existence of either without resorting to philosophical materialism, classical physics, etc. In short, it is meaningless to say that the brain is responsible for consciousness when the brain itself cannot be found to exist in observable reality.
I hope this has been a useful read, it's a bit strange, I feel very much out of my element writing about modern science. It is quite possible that I have misrepresented some of the scientific concepts, theories and views described herein, but I think the reasoning of the paper is sound nonetheless. Again, this was meant more as a persuasive article than a scientific paper, so I apologize in advance to anyone throwing up flags at my lack of citations, etc. It was my hope only that this paper might provide a framework of understanding to help sceptics overcome their predisposed aversion towards the concept of rebirth.
It may be that much more could have been said, hopefully I can expand, revise and clarify this paper based on comments and criticisms, both from others and myself. In the meantime, may it be of more benefit that harm.
i For more on orthodox quantum theory, I can't recommend enough the work of Dr. Henry Stapp, an expert in the field and exceptional advocate of the efficacy of conscious thought in relation to physical reality (http://www-physics.lbl.gov/~stapp/stappfiles.html)
ii This is not meant to be a scientific paper, so I excuse myself from having to substantiate these claims, but for those interested in such studies (and they are numerous), I recommend reading Irreducible Mind, by Edward Kelly et al, as well as the webpage of the Division of Perceptual Studies and University of Virginia. Bruce Greyson also gave a great talk to the UN that is worth watching.
iii Again, I encourage the reader to consult Irreducible Mind, for example: “Near-death experiences seem instead to provide direct evidence for a type of mental functionings that varies ‘inversely, rather than directly, with the observable activity of the nervous system’ (Myers, 1891d, p. 638). Such evidence, we believe, fundamentally conflicts with the conventional doctrine that brain processes produce consciousness, and supports the alternative view that brain activity normally serves as a kind of filter, which somehow constrains the material that emerges into waking consciousness. On this latter view, the ‘relaxation’ of the filter under certain still poorly understood circumstances may lead to drastic alterations of the normal mind-brain relation and to an associated enhancement or enlargement of consciousness.”