Authors:

The problem of knowledge is that there are many more books on birds written by ornithologists than books on birds written by birds and books on ornithologists written by birds

Nassim Nicholas Taleb (2016). “Incerto 4-Book Bundle: Fooled by Randomness The Black Swan The Bed of Procrustes Antifragile”, p.1782, Random House
The problem of knowledge is that there are many more books on birds written by ornithologists than books on birds written by birds and books on ornithologists written by birds