ABSTRACT
This chapter begins by making explicit some of the theses reductionists endorse and antireductionists reject and distinguishing them from views both parties endorse. There is an important asymmetry in these positions and therefore in the arguments each side needs to mount. The reductionist argues for what is in effect a “negative existential” claim-that there are no irreducible biological properties, or perhaps that there are no irreducible biological explanations. Like the denial that there are any ghosts, these denials can never be conclusively established by evidence alone. After all, a search of the whole universe for ghosts would take forever. On the other hand, antireductionism needs only one positive case to prove its point-one irreducible property or explanation. Thus, even when the reductionist successfully disproves a case of alleged irreducibility, there is always the prospect that another counterexample will be found. Nevertheless, both parties to the dispute have tended to focus on the same cases. Indeed, antireductionists often begin their arguments with the analysis of explanations in molecular biology, just where one would think the strength of reductionism is to be found.
