I seem to recall a Mahayana? text where the Buddha assures us that in the event that reincarnation does not occur, Buddhist doctrine will still provide a worthwhile life. It had some of the flavor of Pascal’s Wager.
I can’t track it down though. Does anyone have any leads? My recollection is vague and I trust somewhat inaccurate: sorry.
Well, this isn’t precisely what you’re looking for, but I’ve always liked it:
The Buddha was sitting in the park when his disciple Malunkyaputta approached him. Malunkyaputta had recently retired from the world and he was concerned that so many things remained unexplained by the Buddha. Was the world eternal or not eternal? Was the soul different from the body? Did the enlightened exist after death or not? He thought, ‘If the Buddha does not explain these things to me, I will give up this training and return to worldly life’.
Thus, he approached the Buddha with this question, who replied:
“Suppose, Maunkyaputa, a man were wounded by an arrow thickly smeared with poison, and his friends and companions brought a surgeon to treat him. The man would say: “I will not let the surgeon pull out the arrow until I know the name and clan of the man who wounded me; whether the bow that wounded me was long bow or crossbow; whether the arrow that wounded me was hoof-tipped or curved or barbed.
All this would still not be known to that man and meanwhile he would die. So too, Malunkyaputta, if anyone should say: “I will not lead the noble life under the Buddha until the Buddha declares to me whether the world is eternal or not eternal, finite or infinite; whether the soul is the same as or different from the body; whether an awakened one ceases to exist after death or not,” that would still remain undeclared by the Buddha and meanwhile that person would die.
Whether the view is held that the world is eternal or not, Malunkyaputta, there is still birth, old age, death, grief, suffering, sorrow and despair – and these can be destroyed in this life! I have not explained these other things because they are not useful, they are not conducive to tranquility and Nirvana. What I have explained is suffering, the cause of suffering, the destruction of suffering and the path that leads to the destruction of suffering. This is useful, leading to non-attachment, the absence of passion, perfect knowledge.”
Thus spoke the Buddha, and with joy Malunkyaputta applauded his words.
The Parable of the Poison Arrow (Majjhima-nikaya, Sutta 63)