 The idea that reduction is tied to part-whole relations is frequently alluded to in the literature (esp. Schaffner 1993; Place 1956, 1960). The most elaborate version of this assumption forms part of Causey’s more general picture of scientific unification. Intuitively, and abstracting away from numerous details of his elaborate model (described in terms of theory-reduction), a micro-reduction in Causey’s sense relies on an identification of a property P1 with a property P2, where the syntactical arrangement of the terms forming the complex term ‘P2’ reflect the mereological composition of P1, whereas ‘P1’ does not. ‘P1’ simply refers to the whole without explicitly referring to its parts as ‘P2’ does, but they in fact refer to the same complex. Whereas mereological relations alone are compatible with emergentist or dualist interpretations combining mereological composition and identity seems to ensure a link strong enough to count as a reductive link.