Alexander Rosenberg, Darwinian Reductionism: Or, How to Stop Worrying and Love Molecular Biology. Chicago: University of Chicago Press, 2006. Pp. x+263. US$40.00 HB

mother is always worried about you’. And yet some worrying, including that of your mother, turns out to be justified. Alexander Rosenberg’s new book is an extended argument intended to assuage false concerns about reductionism and molecular biology while encouraging a loving embrace of the two. It collects previously published and newly written material woven together with an overarching narrative: Darwinian theory reductively’ reaches all the way down to the history of macromolecules. Rosenberg sees this as a distinct break with his earlier works (The Structure of Biological Science, 1985; and Instrumental Biology or the Disunity of Science, 1994), where he argued against reductionism conceptualised in terms of Nagelian formal strictures on theory reduction. Ironically, Rosenberg now uses the same argument for reductionism in the context of explanation that he previously used against reductionism in the context of theories: natural selection. The operation of natural selection at the level of macromolecules simultaneously shows that biology is relatively autonomous from physical science and vindicates reductionism – a Darwinian reductionism. Rosenberg frames his analysis in terms of ‘‘biology’s untenable dualism’’, i.e. the joint commitment to physicalism and antireductionism. ‘‘How can you be a physicalist and deny the ‘‘nothing but’’ thesis?... It is this paradoxical state of affairs that makes a perplexing mystery out of the problem of exactly how molecular biology relates to the rest of biology’’ (p. 3). After setting the stage around this puzzle in the Introduction, subsequent chapters unpack