Birth of Tragedy, (Walter Kaufmann translation) Section 1, paragraph 2
In order to grasp these two tendencies [Dionysian and Apollinian], let us first conceive of them as the separate art worlds of dreams and intoxication. These physiological phenomena present a contrast analogous to that existing between the Apollinian and the Dionysian. It was in dreams says Lucretius, that the glorious divine figures first appeared to the souls of men; in dreams the great shaper beheld the splendid bodies of splendid bodies of superhuman beings...
Section 15, paragraph 5 (paragraph 3 in German)
Therefore Lessing, the most honest theoretical man, dared to announce that he cared more for the search after truth than for truth itself—and thus revealed the fundamental secret of science to, to the astonishment, and indeed the anger of the scientific community.
It seems to me that the two quotations above from Birth of Tragedy (1872) have not been discussed enough in Nietzsche commentary. I might have missed something in the vast volume of Nietzsche commentary in various languages, but they certainly have not been emphasised much by the better known commentators of international reputation.
The first quotation introduces the physiological into the idea of the Dionysian and Apollinian as necessary contrasting elements of art. Nietzsche’s phrasing seems to waver between regarding the physiological phenomena of dreams and intoxication as the basis of the Apollinian and the Dionysian, and as analogies for them. In any case, we are invited to see art as the outcome of the struggle between, and unity of, two physiological drives. Surely this distances Nietzshce from a completely non-natural Romantic metaphysics of art. A Romantic conception could seek a basis in nature, but in any case that would reduce the opposition between a Romantic-Metaphysical conception and a Naturalistic-Scientific conception. Maybe it is not a good idea to think of Birth of Tragedy as a left over from ‘Romanticism’, an idea itself which excludes reflection on what Romanticism is.
The second quotation introduces a notion of the relation between science and art which is picked up again in Human, All Too Human (1878). The notion that art and science are connected in the search for truth and that both would die without a continuing search. Sometimes in Human, All Too Human, Nietzsche seems to be saying that art has given way to science in the great search, and this sometimes taken as indicating a break with Birth of Tragedy. But as we see, the idea is already being explored in the earlier book, which already deals with an approach to science I addressed in a post of 5th July ‘Nietzsche Prophet of Karl Popper: Art and Science’.
I’m strongly inclined to doubt that Birth of Tragedy represents a non-naturalistic approach deeply at odds with Nietzsche’s later texts. In some current work on Nietzsche I am concerned with oscillation between aestheticism and scientism (including their combination), and it seems to me that such an oscillation is evident in Birth of Tragedy.