The temptations of God were always more dangerous for mankind than those of Satan.

The discoveries of yesterday are the truisms of tomorrow, because we can add to our knowledge but cannot subtract from it.

I am not sure whether ethical absolutes exist. But I am sure that we have to act as if they existed or civilization perishes.

In the social equation, the value of a single life is nil; in the cosmic equation, it is infinite... Not only communism, but any political movement which implicitly relies on purely utilitarian ethics, must become a victim to the same fatal error. It is a fallacy as naïve as a mathematical teaser, and yet its consequences lead straight to Goya's Disasters, to the reign of the guillotine, the torture chambers of the Inquisition, or the cellars of the Lubianka.

Some of the greatest discoveries...consist mainly in the clearing away of psychological roadblocks which obstruct the approach to reality; which is why,post factum they appear so obvious.

Scientists are peeping toms at the keyhole of eternity.

Two half-truths do not make a truth, and two half- cultures do not make a culture