I am not entirely sure that I agree with the argument I am about to make. However, I do find it at least plausible and I have not seen it made before. I think this argument is worth somebody making, and I think it is worth doing here.
That is: I would like to make a Buddhist argument against rebirth. An argument against rebirth on Buddhist grounds.
I say “on Buddhist grounds” to make the methodological caveat that this is not, to my knowledge, an argument that any Buddhists have made in the past. Rather, it is a Buddhist argument in the sense that I am a Buddhist and I myself make the argument on Buddhist grounds, as a Buddhist theologian. It disagrees with most Buddhist positions that have been taken in the past – just as Nāgārjuna and Linji and Zhiyi and the author of the Lotus Sūtra all did when they made their radical revisions of the Buddhist path as known up to that time. Many Buddhists of course disagree with these thinkers, as well they should; Buddhist sectarianism expresses real and important differences. Still, most of us accept that the arguments of Linji or the Lotus Sūtra are legitimately Buddhist despite their radical differences from the Buddhism that came before them.
So to the argument itself. Most of us, it is not controversial to say, are deeply attached to our selves. The typical claim made by every non-Pudgalavāda Buddhist is that this is a problem. The idea of self is not only an illusion, it’s a harmful illusion, because it leads us to an attachment to something that does not deserve that attachment. We cling to the self and what is associated with it. In the Cūla Sīhanāda Sutta, the Buddha says that plenty of other teachers have warned against other types of clinging; what is original to him, what makes his understanding the fullest, is that he specifically warns against clinging to an idea of self.
And it seems to me that that sort of clinging, the clinging to self, is exactly what lies behind much of the widespread human belief in an afterlife. We are so attached to the idea of our selves existing that we cannot bear the thought of those selves ceasing to be, cannot even imagine it. We often act and speak as if death is something unusual that won’t really happen to us. This latter insight about our denial of death is hardly new to me; Freud, for one, wrote:
We have shown an unmistakable tendency to put death aside, to eliminate it from life. We attempted to hush it up, in fact, we have the proverb: to think of something as of death. Of course we meant our own death. We cannot, indeed, imagine our own death; whenever we try to do so we find that we survive ourselves as spectators. The school of psychoanalysis could thus assert that at bottom no one believes in his own death, which amounts to saying: in the unconscious every one of us is convinced of his immortality. (Reflections on War and Death, chapter 2)
But Freud was no Buddhist. The point I want to make here is the Buddhist one: belief in an afterlife, including rebirth, is a clinging to self. It is our obsession with our selves and our own existence that makes us postulate the continuance of that existence, whether in a heaven or in rebirth. Without that unhealthy obsession, we wouldn’t need that belief: we would be in the healthier world of Epicurus and Lucretius, where “death is nothing to us”. From a Buddhist perspective, the existential dread that greets the thought of our complete nonexistence is a healthy spiritual practice, one that helps us realize just how unsustainable our attachment to self turns out to be.
So too, it matters how much empirical observation has shown a connection between the mind and the brain. We have long known that changes to the brain, like drugs or injuries, affect the mind; contemporary neuroscience has explored this connection in excruciating detail and it has been quite successful in doing so, a progressive research program. The Epicureans appear to have been right that the mind is in that sense material. And so it seems logical to presume, with the Epicureans, that when the brain stops functioning, the mind will stop with it. By contrast, there seems to be far less evidence that minds can exist in any sense not connected to physical brains. Given the state of the empirical evidence as I understand it, rebirth appears to be not merely a belief that sustains our attachment to self, but an illusion that sustains our attachment to self: exactly the sort of thing that Buddhism is supposed to be all about fighting against.
Now there is one major problem with a Buddhism that rejects rebirth, one that Jan Westerhoff and I have both noted in the past: if one rejects rebirth and also accepts the doctrine that the sole good in life is the reduction of dukkha (suffering, unsatisfactoriness), then it would seem that the best way to proceed in life is to kill oneself – or, if one is more altruistically oriented, to kill others. Wilhelm Halbfass points to a group called the Saṃsāramocakas, described in some classical Sanskrit texts, who supposedly took up a related conclusion and went around killing people to eliminate their dukkha. But we only know the Saṃsāramocakas through their opponents; it is not clear they actually existed. Nearly all the rest of us human beings would take their supposed position as a genuine reductio ad absurdum: the prasaṅga (consequence) of these positions is one that we cannot accept, and therefore we must either accept rebirth or accept goals in life other than the reduction of dukkha.
Westerhoff takes the first of these two options: he thinks that as Buddhists we must be entirely committed to dukkhanirodha and that we must therefore grasp at whatever straws we can find to prove the existence of rebirth. I do not. A core tenet of Buddhism has always been the need to see things yathābhūtam, just as they are, and it seems to me that a rebirth doctrine does not do this; it is one more form of illusion, and, if my argument above is correct, an illusion that leads us to exactly that form of clinging which the Buddha is most concerned to reject. Rather, I think we must take the second option, and allow that there is more to life than dukkhanirodha, as most self-identified Buddhists have in practice done throughout history.