...Ravens and Writing-Desks and such...

It's been a subject of analysis for years. Decades, even. Almost, but not quite, centuries.

When I first heard it, it came with its own answer:
-- Q: Why is a Raven like a Writing-Desk?
-- A: The higher, the farther.
Garbage in, garbage out.

But it's been considered in depth by much cleverer minds than mine. See here for one such disquisition.