Extended Simples and the Argument from Heterogeneity

Perhaps the most commonly discussed argument against the possibility of extended simples is the argument from heterogeneity. The argument states that, if extended simples are possible, then extended simples which exhibit intrinsic qualitative variation across space (or spacetime) are also possible [Premise 1]. But, the argument goes, it is impossible for an extended simple to exhibit intrinsic qualitative variation across space (or spacetime) [Premise 2]. Thus, extended simples are impossible. I argue that there is a serious problem with the argument from heterogeneity: the best arguments in support of the first premise undermine support for the second. Thus, there appears to be no good reason to accept both premises.