Gene-centered view of evolution Richard Dawkins and George C. Williams, other biologists and philosophers have expanded and refined the selfish-gene theory, such as John Maynard Smith, George R. Price, Robert Trivers, David Haig, Helena Cronin, David Hull, Philip Kitcher, and Daniel C. Dennett. The gene-centric view has been opposed by Ernst Mayr, Stephen Jay Gould, David Sloan Wilson, and philosopher Elliott Sober. An alternative, multilevel selection (MLS), has been advocated by E. O. Wilson, David Sloan Wilson, Sober, Richard E. Michod, and Samir Okasha. Writing in the "New York Review of Books", Gould has characterized the gene-centered perspective as confusing book-keeping with causality. Gould
The Selfish Gene to make some critical distinctions, in particular, the difference between group selection for group advantage and group selection conveying individual advantage. A good deal of objection to "The Selfish Gene" stemmed from its failure to be always clear about "selection" and "replication". Dawkins says the gene is the fundamental unit of selection, and then points out that selection doesn't act directly upon the gene, but upon 'vehicles' or 'extended phenotypes'. Stephen Jay Gould took exception to calling the gene a 'unit of selection' because selection acted only upon phenotypes. Summarizing the Dawkins-Gould difference of view, Sterelny says: The word 'cause'