Every desire is a felt lack — a state of want, tension, or pain. Satisfaction, when it arrives, is merely the removal of a particular discomfort, not the achievement of a positive good. And satisfaction, once achieved, generates either boredom (the absence of new desire) or immediately makes way for a new desire. The will oscillates endlessly between suffering and boredom, and only the momentary transition between them — the brief instant of satisfaction — is pleasurable. This is the structure of all wanting, from hunger to ambition, and it cannot be reformed without eliminating the will itself.
Schopenhauer reserves his sharpest polemical energy for philosophical optimism — above all, Leibniz's claim that this is the best of all possible worlds. This is not merely wrong, Schopenhauer argues, but obscene: to claim that existence is preferable to non-existence, when the evidence of suffering is everywhere visible, is an insult to those who suffer. The world would be better if it did not exist, or more precisely: non-existence is not a harm, while existence involves guaranteed suffering. Pessimism is not a counsel of despair but an honest reckoning with what the will has made of the world.
The practical upshot of Schopenhauer's pessimism is not nihilism but a reorientation of values. If suffering is structural, then the only genuine wisdom is the wisdom that reduces our exposure to the will's demands: a life lived with modest expectations, genuine appreciation for moments of beauty and rest, compassion for others in their shared predicament, and progressive detachment from the drives that promise fulfilment they cannot deliver. The pessimist who has understood the structure of desire is, paradoxically, better equipped for equanimity than the optimist whose expectations will always be disappointed.
Schopenhauer's pessimism is most systematically stated in The World as Will and Representation (Book Four, §§56–58) but found its widest readership in the essays and aphorisms of Parerga and Paralipomena (1851), particularly "On the Suffering of the World" and "The Vanity and Suffering of Life".