 So features of our theories that appear entirely contingent, from the point of view of physics, are necessary to account for the complexity of the observed universe and the very possibility of life. The fine-tuning argument starts from a sense of unease about this situation: shouldn’t something as fundamental as the complexity of the universe be explained by the laws or basic principles of the theory, and not left to brute facts regarding the values of various constants? The unease develops into serious discomfort if the specific values of the constants are taken to be extremely unlikely: how could the values of all these constants be just right, by sheer coincidence?