In defense of gradualism

On the basis of his Operator Theory (OT), which stresses the requirement of dual closure, Jagers argues that all operators that are at least as complex as cells qualify as organisms. I argue that while this does indeed provide us with a set of clear and consistent criteria that unambiguously demarcate organisms from other things, it is hard to assess their adequacy because not much is said about the purpose(s) they are intended to serve. Without a specifi cation of the latter, consistency and clarity as such may not count for much. I furthermore argue that if more traditional criteria of organismality are invoked-notably metabolism and reproduction- new scientifi c insights suggest that the gradualist school that Jagers rallies against makes more sense than Jagers is willing to grant. In some cases we might be forced to accept the fuzziness and ambiguity inherent in "degrees of organismality" that Jagers loathes. It is important to acknowledge that the fuzziness and ambiguity do not stem from vagueness in the list of criteria and in the meanings of the criteria that are invoked, but from the diversity and variety that we fi nd in nature.

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