David Deutsch

The Science Show: The Anthropic Universe, 2/18/2006.

"If we nudge one of these constants just a few percent in one direction, stars burn out withing a million years of their formation, and there is no time for evolution. If we nudge it a few percent in the other direction, then no elements heavier than helium form. No carbon, no life. Not even any chemistry. No complexity at all. "