Central to the debate between Humean and anti-Humean metaphysics is the question of whether dispositions can exist in the absence of categorical properties that ground them (that is, where the causal burden is shifted on to categorical properties on which the dispositions would therefore supervene). Dispositional essentialists claim that they can; categoricalists reject the possibility of such ?baseless? dispositions, requiring that all dispositions must ultimately have categorical bases. One popular argument, recently dubbed the ?Argument from Science?, has appeared in one (...) or another form over much of the last century and purports to win the day for the dispositional essentialist. Taking its cue from physical theory, the Argument from Science treats the exclusively dispositional characterizations of the fundamental particles one finds in physical theory as providing a key premise in what has been called a ?decisive? argument for baseless dispositions. Despite sharing the intuition that dispositions can be baseless, I argue that the force and significance of the Argument from Science have been greatly overestimated: no version of the argument is close to decisive, and only one version succeeds in scoring points against the categoricalist. Not only is physical theory more ontologically innocent than defenders of baseless dispositions seem to appreciate, most versions of the Argument from Science neglect important ways that dispositions could be grounded by categorical properties. (shrink)