Marvin Minsky needs no presentation: his unflinching atheism was proverbial as the video below clearly testifies.
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.