“Indeed, Earth could not be without a Hujja (a proof, a prophet or his vice), either manifest or occult.”

Source: Germania (98), Chapter 35

Hélas! les vices de l’homme, si pleins d’horreur qu’on les suppose, contiennent la preuve (quand ce ne serait que leur infinie expansion!) de son goût de l’infini.
"Le poème du haschisch," I: Le goût de l’infini http://fr.wikisource.org/wiki/Les_Paradis_artificiels_-_I
Les paradis artificiels (1860)

Book II, Ch. 21, sec. 70
An Essay Concerning Human Understanding (1689)

The Reappearance of the Christ and the Masters of Wisdom (1980)

Source: A New Concept of the Universe (1953), p. 139

The second sentence is often misquoted as “Science has proof without any certainty. Creationists have certainty without any proof.” or “Religion gives us certainty without proof; science gives us proof without certainty.”
Context: Bigotry and science can have no communication with each other, for science begins where bigotry and absolute certainty end. The scientist believes in proof without certainty, the bigot in certainty without proof. Let us never forget that tyranny most often springs from a fanatical faith in the absoluteness of one’s beliefs.

Source: The World Without Us

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Truth and Tension in Science and Religion