Having accused the ascetic ideal of ruining both taste and health, Nietzsche shifts his focus to the main topic of the essay: what the ascetic ideal means. The ascetic ideal is so powerful, Nietzsche suggests, because it interprets all human history and human experience in terms of its one goal. It interprets everything, and denies the validity of any alternative interpretaton. Nietzsche asks whether there is any other will that might oppose the monstrous power of the will expressed by the ascetic ideal.
Nietzsche first considers the suggestion that science is such an opposing will. Science has been able to stand on the strength of its own interpretations without calling on the existence of God, an afterlife, or asceticism. Nietzsche opposes this suggestion, claiming that science lacks the positive will that characterizes ascetic ideals, and where it does arouse passion, it manifests itself only as the latest incarnation of the ascetic ideal itself.
Scholars may appear to have independent wills because they renounce faith of all kinds. They demand proof and rigorous reasoning, and will not base their claims on faith in God or religious doctrines. However, Nietzsche suggests, they renounce these faiths only in favor of a different faith: a faith in truth. As long as they have faith in truth, they cannot speak as truly free spirits: "nothing is true, everything is permitted."
Science's obsession with truth leads it to value facts and facts alone. Interpretation relies on a distortion of the truth, a particular way of looking at the truth, and so a faith in absolute truth calls for pure, uninterpreted facts. This abstinence from interpretation is as much an expression of the ascetic ideal as the chastity of a priest. Science's faith in the absolute and metaphysical value of truth is essentially a faith in the ascetic ideal. Science, like everything else, requires a will, a "faith" that will motivate it and direct it. That scholars deny that they allow themselves to be driven by any will is only a manifestation of their ascetic ideals.
Not even truth should be believed in blindly. We have a tendency to see truth as a justification in itself, just as the religious see the word of God as a justification in itself. Nietzsche asserts: "The will to truth requires a critique ... the value of truth must for once be experimentally called into question." Even our faith in truth needs to be justified.
Science, says Nietzsche, does not create values: it always exists in the service of some other values. Thus, it cannot be the force that opposes the ascetic ideal. Rather, it and the ascetic ideal are together in their valuing of truth as being beyond criticism. Science may seem opposed to religion, but it has merely replaced God with truth as an absolute, transcendent ground that justifies and explains existence.