(This entry touches upon some themes discussed with greater rigor, thoroughness, and scholarliness in my "No Self? A Look at a Buddhist Argument," International Philosophical Quarterly, vol. 42, no. 4 (December 2002), pp. 453-466.)
For Buddhism, all is dukkha, suffering. All is unsatisfactory. This, the First Noble Truth, runs contrary to ordinary modes of thinking: doesn't life routinely offer us, besides pain and misery and disappointment, intense pleasures and deep satisfactions? How then can it be true that sarvam dukkham? For the Buddhist, however, what is ordinarily taken by the unenlightened worldling to be sukha (pleasure) is at bottom dukkha. Why? Because no pleasure, mental or physical, gives permanent and plenary satisfaction. Each satisfaction leaves us in the lurch, wanting more. A desire satisfied is a desire entrenched. Masturbate once, and you will do it a thousand times, with the need for repetition testifying to the unsatisfactoriness of the initial satisfaction. Each pleasure promises more that it can possibly deliver, and so refers you to the next and the next and the next, none of them finally satisfactory. It's a sort of Hegelian schlechte Unendlichkeit. Desire satisfied becomes craving, and craving is an instance of dukkha. One becomes attached to the paltry and impermanent and one suffers when it cannot be had.
There is more to it than this, but this is the essence of it. The thing to note is that the claim in the First Noble Truth is not the triviality that there is a lot of suffering in this life, but that life itself, as insatiable desiring and craving for what is unattainable to it, is ill, pain-inducing, profoundly unsatisfactory, and something to be escaped from if possible. It is a radical diagnosis of the human predicament, and the proposed cure is equally radical: extirpation of desire. The problem for the Buddhist is not that some of our desires are misdirected; the problem is desire itself. The soulution, then, is not rightly-ordered desire, as in Christianity, but the eradication of desire. The root of suffering is desire and that root must be uprooted (e-radi-cated).
Although Buddhism appears in some ways to be a sort of 'empirical religion' -- to hazard an oxymoron -- the claim that all is suffering involves an interpretation of our experience that goes well beyond the empirically given. Buddhism, as a development from Hinduism, judges the given by the standard of the permanent. Permanence is the standard against which the ordinary satisfactions of life are judged deficient. Absolute permanence sets the ontological and axiological standard. The operative presupposition is that only that which is permanent is truly real and truly important. But if, as Buddhism also maintains, all is impermanent, then one wonders whence the standard of permanence derives its validity. If all is impermanent, and nothing has self-nature, then the standard is illusory. If so, then we have no good reason to reject all ordinary satisfactions.
For Buddhism, the fundamental problem is suffering in the radical sense above explained, and the solution is entry into nibbana by the extirpation of desire, all desire (including even the desire for nibbana), as opposed to the moderation of desire and its redirection to worthy objects. I reject both the diagnosis and the cure. The diagnosis is faulty because incoherent: it presupposes while denying the exstence of an absolute ontological and axiological standard. The cure is faulty because it issues in nihilism, as if the goal of life could be nonexistence.
I am talking about primitive Buddhism, that of the Pali canon. Attention to the Mahayana would require some qualifications.
So one reason I am not a Buddhist is that I reject the doctrine of suffering. But I also reject the doctrines of impermanence and 'no self.' That gives me two more reasons.
But I should say that I take Buddhism very seriously indeed. It is deep and sophisticated with a rich tradition of philosophical commentary. Apart from its mystical branch, Sufism, I cannot take Islam seriously --except as a grave threat to other religions and indeed to civilization itself. But perhaps I have been too much influenced by Schopenhauer on this point.