"For the scientist the formulation of questions is almost the whole thing. The answers, when found, only lead on to other questions. The nightmare of the scientist is the idea of complete knowledge. He shudders to think of such a thing. Compare this with the certainty that belongs to religion, and you will see how different science is from religion. Religion replaces doubt with certainty. Science holds an infinity of doubt, and implies a faith. Faith in what? Perhaps in nothing; just a capacity to have faith; or if there must be faith in something, then faith in the inexorable laws that govern phenomena."