A Critique of Cosmological Natural Selection

Mathematical physicist Lee Smolin has proposed a theory of Cosmological natural selection which, he argues, explains the existence of our life-supporting universe, and which, he claims, is superior to Anthropic Principle explanations. I will argue in this paper that the theory of Cosmological natural selection does not provide an improvement upon the Weak Anthropic Principle. According to current mathematical physics, there are many aspects of our physical world which are contingent rather than necessary. These include such things as the values of the constants in elementary particle physics, the values of the co-efficients in the laws of physics, and the initial conditions in General Relativistic models of the Universe. These can be referred to collectively as the parameters of physics. Study has revealed that the existence of life is very sensitively dependent upon the values of these parameters. If a universe had values for these parameters only slightly different from the values they possess in our own universe, then that universe would be incapable of supporting life. Hence, people have sought to explain why a life-supporting universe exists. The Weak Anthropic Principle (WAP) provides one such explanation. The WAP hypothesizes the existence of a collection of universes, with different universes in the collection having different values for the parameters of physics. The WAP suggests that some of these universes have the combination of parameter values which permit life, and in at least one such universe, life and intelligent life exists. Amongst all the possible contingent values for the parameters of physics, intelligent life can only observe those values consistent with its own existence, (see Barrow and Tipler, [1]). Opposing the Weak Anthropic Principle is Lee Smolin’s theory of Cosmological natural selection. Smolin argues that the introduction of natural selection into cosmology can explain the existence of our life-supporting universe. He claims that to argue in the manner of the anthropic principle, “is not to reason, it is simply to give up looking for a rational explanation,” (Smolin, [2], p39). To expound Smolin’s idea, it is first necessary to appreciate that natural selection can be precisely defined mathematically, in complete abstraction from 1This work was completed with the kind assistance of John Preston and David Oderberg from the University of Reading, Department of Philosophy.