"But if ether is nothing but an hypothesis explanatory of light, air on the other hand, is a thing that is directly felt; and even if it did not enable us to explain the phenomenon of sound, we should nevertheless always be directly aware of it, and above all, of the lack of it in moments of suffocation or air-hunger. And in the same way God Himself, not the idea of God, may become a reality that is immediately felt; and even though the idea of God does not enable us to explain either the existence or essence of the Universe, we have at times the direct feeling of God, above all in moments of spiritual suffocation. And the feeling, mark it well, for all that is tragic in it and the whole tragic sense of life is founded upon this — this feeling is a feeling of hunger for God, of the lack of God. To believe in God is, in the first instance... to wish that there may be a God, to be unable to live without Him."