"self-styled men of knowledge"

Nietzsche begins by saying that science perceives itself as the true philosophy of reality, holding "that [it] possesses the courage for itself… and has up to now survived without God, the beyond and the virtues of denial." But au contraire, Nietzsche counters:

"Science today has absolutely no belief in itself, let alone an ideal above it – and where it still inspires … ardor… and suffering at all, it is not the opposite of the ascetic ideal but rather the latest and noblest form of it."

Yes, science is rigorous and can be seen as "craftsmanship." Yet "science today is the hiding place for every kind of discontentment, disbelief, … it is the unrest of the lack of ideals."

In fact, Nietzsche maintains that there is no science without presuppositions, "that a faith must be there first… so that science can acquire from it a direction, a meaning… a method, a right to exist." There point is, science presupposes another world. Here should be the confession of the scientist:

"We godless men and anti-metaphysicians derive [meaning] from a faith millennia old, the Christian faith which was also Plato’s, that God is truth and that truth is divine."

See Friedrich Nietzsche, On the Genealogy of Morals, trans. Walter Kaufmann, (New York: Vintage Books, 1969),