In the mid-1870s Nietzsche went through a phase of celebrating science worship based on viewing natural science as the paradigm of all genuine knowledge. The period came to an end with Human, All-too-Human.
In the early 1880s a skepticism towards science developed that questioned whether science could picture reality understood as the world-as-it-is-in-itself. Nietzsche rejected the Kantian distinction between a noumenal and phenomenal world. In his later works he repeatedly endorses a scientific perspective whilst questioning science from the perspective of an artistic interpretation of phenomena).
Positivism: the death rattle of the Enlightenment.
That's Nietzsche:
Against positivism, which halts at phenomena,'There are only facts',I would say: No, facts is precisely what there is not, only interpretations. We cannot establish any fact 'in itself': perhaps it is folly to want to do such a thing (WP, 267).