There are not a few problems in the natural sciences of which a man cannot speak justly without calling metaphysics to his aid; not technical words about knowing and being, such as make a show in the schools, but that wisdom of thought which was before all physics, lives with it, and will endure after it.

In: John Stuart Blackie, The Wisdom of Goethe, Philosophy, Metaphysics, Logic, Truth and Science (pp. 160-161), William Blackwood & Sons. Edinburgh, Scotland. 1883