Why Projective Geometry?

In a letter from GW to Gerald Yorke on 23 May 1970 he explains – below is the extract – This is around the time he was publishing ZZ2

In contemplation found the question how & why did evolution produce minds that are full of horseshit & hard to control requiring some effort to bridle & tame?  Meditation is sometimes difficult without a lot of practice. Here is another answer by GW.