Nietzsche on metaphysics as symptom
In some, it is their weaknesses that philosophize; in others, their riches and strengths. The former need their philosophy, be it as a prop, a sedative, medicine, redemption, elevation, or self-alienation; for the latter, it is only a beautiful luxury, in the best case the voluptuousness of a triumphant gratitude that eventually has to inscribe itself in cosmic capital letters on the heaven of concepts.
All those bold lunacies of metaphysics, especially answers to the question about the value of existence, may always be considered first of all as symptoms of certain bodies; and if such world affirmations or world negations lack altogether any grain of significance when measured scientifically, they give the historian and psychologist all the more valuable hints as symptoms of the body, of its success or failure, its fullness, power and highhandedness in history, or of its frustrations, fatigues, impoverishments, its premonitions of the end, its will to an end.
Nietzsche, The Gay Science, Preface to the Second Edition
We take care not to say that the world is worth less […] the whole attitude of man […] as judge of the world who finally places existence itself on his scales and finds it too light—the monstrous stupidity of this attitude has finally dawned on us and we are sick of it. Nietzsche, The Gay Science, Book V, §346