Ellis replies: David Gentile says that “reductionism works every time we are able to test it.” But the point of my article is that it works, and can be tested, only when we exclude the real world; it cannot tell you what move a chess player will make next, for example, or what will happen tomorrow on the stock exchange. “By induction,” says Gentile, “we can theorize that it always works.” Yes you can, and that is an untestable conjecture; whether it is a scientific proposition is therefore open to question. He says that no experimental evidence has established a boundary beyond which reductionism fails. Yes, there is evidence for such a boundary: As pointed out by Jean-Marie Lehn, 1 it is the level of supramolecular chemistry. At and above that level, history and context become as important as physics; a reductionist account cannot, for example, predict the sequence of bases in the DNA of wheat, or what gene will be read next in a cell in a bee as it dances to convey information.
Dave Rauschenfels says, “Assuming that all biological systems are subject to determinate laws, one sees that free will terminates. Determinate systems simply forbid its existence.” But the assumption is invalid; biology is subject to physics, which at its foundations is not determinate. The relation to consciousness is not clear, and has been the subject of intense debate by major quantum theorists, but please let’s admit that quantum theory underlies biology. Furthermore, as Anton Zeilinger said in remarks he made at the Princeton University gathering to honor John Wheeler in March 2002, if free will does not exist in a meaningful sense, the process of scientific investigation cannot take place; scientific procedure assumes we are able to make conscious choices about what is a sound theory and what is not.