Abstract
The systems perspective, as applied to biology, involves regarding organisms as systems consisting of biological molecules in motion; its goal is to determine which interacting molecules make up the organism and how their interactions change over time. I argue here that Nicanor Austriaco’s attempt at reformulating Aristotelian-Thomistic hylomorphism in terms of the systems perspective fails because it looks to systems biology to answer questions that only natural philosophy can answer. These questions include whether an organism is collection of parts having accidental unity or is a substance, what constitutes an emergent property, and what role the final cause plays in understanding organisms. In addition, insufficient attention is paid to the Aristotelian-Thomistic tenet that the soul can only be united to a suitably disposed body, namely, one with organs. Nothing is offered to show that this tenet can be accorded with a perspective that views organisms as networks of interacting molecules.