You can put this another way by saying that while in other sciences the instruments you use are things external to yourself (things like microscopes and telescopes), the instrument through which you see God is your whole self. And if a man's self is not kept clean and bright, his glimpse of God will be blurred - like the Moon seen through a dirty telescope. That is why horrible nations have horrible religions: they have been looking at God through a dirty lens.
C. S. Lewis