 It could be argued that atomism can be reconciled with treating the things that are significant for us as substances only if one thinks of the atoms as existing only in order to constitute such objects. This would be so if God had created the atoms so as to construct macroscopic objects from them, just as we create the parts of artefacts only for the sake of the artefacts. It might be argued that the same objective could be reached without theism if there is irreducible teleology in nature that gives significance to the rest. Thomas Nagel’s view in his (2012) either adopts or comes close to this position. But Nagel’s position seems to challenge natural science within its own realm, whereas the “theological artefact” model does not. It is uncontroversial that an artefact, such as a clock, can be both mechanical and defined as the kind of thing that it is by its function. Applying this model to nature as a whole would involve bringing theology into Aristotle’s metaphysics more directly than he, or indeed Aquinas, intended. The notion that an object is what it is because of its use is found in Heidegger (1927 [2008]) but this is the use to which we put objects, not a divinely ordained teleology; Heidegger’s theory imports the subjective perspective implicit in phenomenology, and this runs counter to Aristotle’s objectivism. If, however, one takes the teleology to be designed into creation, this subjectivism is eliminated, and if one thinks that teleology is the key determinant of substantial identity, as with artefacts, then one has preserved the doctrine of substance, rather than replacing it by a mere theory of function. This would have the consequence that if the designer could change the purpose of an object whilst leaving it physically unchanged—as we do if we use a knife as a screwdriver—then its substantial identity will change (Schillebeeckx, 1968, Dummett, 1987, Robinson, 2016)