The idea that we are reborn again and again in a world where suffering is ubiquitous, until through our practice of the Dharma, we are liberated, is fundamental to traditional Buddhism. Liberation is fundamentally liberation from the "rounds of rebirth". And yet for many Westerners the idea of rebirth is not one they believe in. The arguments over rebirth sound to my ears very much like the argument over creation vs evolution. Neither side is able to conclusively prove their assertions, since both are by definition beyond proof. And yet one must admit that every received tradition of Buddhism explicitly accepts rebirth on the one hand; and that any solid scientific evidence for it is entirely lacking on the other. Where does this leave us?
If we leave aside the aberrant versions of rebirth which assume any kind of continuity for the personality, we are still left with something of a quandary in how we explain why the Buddha might have taught (much less believed in) rebirth, and how it is possible to have continuity between lives. What must be posited is some aspect of the individual - entirely beyond the scope of measurement - which survives the death of the body, and becomes incorporated into a new being at some point giving them the experience of the results of the actions of the previously dead person. As someone with scientific training I feel this is well into the territory of superstition and irrational belief.
However I would argue that there is a useful Buddhist approach to this issue, that is doctrinally valid and methodologically useful. It stems from my growing belief that the Buddha was not offering an ontology, not offering us definite statements on "how things are", but only ways in which we could experience for ourselves the way things are. Yes, the Buddha, did give a series of metaphors for this experience, and did talk about having had that experience, but I am more and more convinced that his message was about how to reproduce that experience without making any definite statements about the content of it. After all the experience is repeatedly said to be beyond words. Words about the Awakening experience, then, I take to form part of the recipe, or even the exhortation to bake, but are not the cake itself.
What happens if we apply this hermeneutic to the teachings about karma and rebirth?
The fact that actions have consequences is not in dispute. This much is obvious to even the least gifted observer of human life. How we go about our lives, how we behave, has a strong determining effect on our experience of life. The Buddha famously equated karma with cetanā or intention. Our attitudes, our mental landscape, is the most powerful determinant of our experience of the world. What we can know is limited by our senses and our mind. My understanding of the Buddha's message is that we are so caught up in the wash of sensory input and mental activity that we make categorical errors in interpreting our experience. As a result the Buddha describes the senses, and the processes which make up our being, as being on fire. Being (or bhava, becoming) is like fire, and the fuel is greed for pleasure, aversion to hatred, and the categorical delusions we have towards experience. Professor Gombrich has gone into this use of the fire metaphor in some detail. He further points out that in the Nidana chain the word usually translated as "clinging" or "grasping" is more straight-forwardly simply fuel. Desire (taṇhā) is the fuel (upādāna), which sustains becoming (bhava). The Buddha, according to the professor, describes being as "a blazing mass of fuel" (upādānakkhandha). The goal of the Buddhist is to blow out that fire - nibbāna.
The way to put out the fire is to deprive it of fuel - to cut off the greed and hatred which keep bhava burning. There is nothing here which requires this process to operate over more than one life. We keep the fire burning in the moment, and can blow it out through insight into the process which creates a decisive reorientation to the experience of the senses. Although the insight is said to come from meditation, the background to meditation is ethics. How we act is important because, positively, it creates the conditions for our sustained reflection on the nature of experience.
Now suppose that we believe that when we die that we personally simply cease to exist. That we personally will never experience the consequences of our actions if they have not already manifested. This would be a major flaw in the program to restrain unethical behaviour. Ethical behaviour, let me repeat, is not an end in itself, but a necessary pre-requisite for bringing about the conditions (calm and concentration) where insight can arise. It would make more sense to inculcate a belief that there was no escape from the consequences of one's actions, not even death, because that would make for a more effective training program in ethics.
Generally speaking we only act unethically if we feel forced to by the circumstances (and therefore fully expect unpleasant consequences but accept them), or if we think we can get away with it! Surely we have all done things when we thought we could get away with it, that under public scrutiny we would not endorse - trifling infringements on the whole. As Buddhists we try to keep the bigger picture in mind, but until we have a substantial experience of insight (and even to some extent afterwards) there is always this delusion that "it won't matter". We think we can "get away with it". A most graphic example of this is found in the Vinaya considered as a whole. If we accept that a rule banning a behaviour would only have been instituted if that behaviour was found in the Sangha, then the early Sangha were a deviant bunch! Many times, of course, a rule is made simply because the local villagers complain that monastics are acting like lay people. But this refrain is so constant in the Vinaya that one suspects that very few of the disciples were serious about spiritual practice.
The Buddha is in effect acting like a parent or guardian in providing behavioural limits for a child. He does this because he knows that freedom from remorse is a necessary condition for a calm body and concentrated mind, which are in turn necessary for achieving insight into the nature of experience. (see for instance the first two suttas in the AN chapter on 10's). While we continue to make the categorical errors we are like drunks or madmen who are a danger to ourselves and others. I don't think I need to stress that we are not talking about psychopaths, incapable of experiencing remorse, here, but the "average" person.
To me it suggests that from a Buddhist perspective is it practically advantageous to believe that I personally will experience the consequences of my actions, death notwithstanding. This is not to say anything about whether such a belief is true or not true, in either a relative or ultimate sense. It may even be untrue, and yet we are better off believing it because it will help us achieve lack of remorse. It is a provisional belief that can be abandoned on the attainment of insight, because it will then no longer be necessary. This is not the same as agnosticism. It requires a commitment to taking responsibility for one's actions now, in the past, and in whatever future may come. What is true in this case is that unless we can make some kind of imaginative leap which allows us to see the consequences of our actions coming home to us, we will continue to think that some actions (of body, speech or mind) do not matter. Everything we do, say, and think matters.
This approach to belief, allowing for provisional belief in something which may not be ultimately valid but which has advantages, is foreign to Western thinking as far as I know. The "debate" between creationists (or their bastard offspring the "intelligent design" lobby) and the people advocating scientific rational humanism both seem to adopt positions which assume that belief is an absolute - you either believe in X or not (and you are either enlightened or a fool as a result). In fact I think a lot of people are better off for believing in a loving and merciful god, if only because existence might be unbearable without that belief. "Love thy neighbour" is in line with my highest aspirations.
To sum up then, I think that a Buddhist approach to belief is fundamentally different to the prevailing Western notions. Instead of asking whether a belief is true or not, and arguing from that basis, we Buddhists ask ourselves "is it helpful"? Helpful is anything in the ethical sphere which helps us achieve calm and concentration. It is axiomatic for Buddhists that anything which is harmful to others cannot afford us calm and concentration - something which is borne out by experience. "True" and "false" matter far less than kusala (helpful) and akusala (unhelpful). So any argument over whether karma and rebirth are "true" in the Western sense are kind of missing the point. It is better, ie more helpful, to believe that you cannot escape the consequences of your actions because that will make you more sensitive to how you act in the present. This approach frees us from having to explain every detail of the doctrine in rational terms, a task which I think is impossible in any case. It also means that we are not so likely to want to fight over the "truth".
image: from Sonofwalrus on Flickr