[pnin]

Since you provide a zoological metaphor, let me offer an alternative. Category theory is much more like Goethe's work on the /Urpflanze/ (primeval plant). Linné had developed a way of systematically naming species of plants, but Goethe was not satisfied by this approach.

Goethe wanted to find an underlying pattern common to all plants which would explain how plants grow and develop. Something like a "universal grammar" (to draw an anachronistic parallel to Chomsky) of plants. Goethe called this his "morphological" method and wrote about it in "On the metamorphosis of plants".

One caveat: this paints a slightly too esoteric picture of category theory. Goethe was very idiosyncratic as a scientist, whereas category theory, far from being esoteric, is a common language for all of modern mathematics.