Marvin Minsky needs no presentation: his unflinching atheism was proverbial.
Less well known, as the above video shows, his connection to Russian Cosmism. Sagan, Asimov and other East coast Russian-Jewish immigrants were all permeated by the idea of Tsiolkovsky. See also this.
In the brilliant words of Bertrand Russell:
A good world needs knowledge, kindness and courage. It does not need a regretful hankering after the past or a fettering of the free intelligence by the words uttered long ago by ignorant men.