 Taurellus’s immaterialism about the basic constituents of the natural world derives from considerations concerning the substantiality of created beings. Taurellus maintains that creatures, in one sense, are not separated from God and that, in another sense, they are separated from God. As to the first sense, he argues that “since an infinite substance fills out everything, nothing can be separated from it”. As to the second sense, we differ numerically from God “not with a view to God’s being in us and our being in him but in the respect that we differ due to our substance” (PT: 412). Hence, God is characterized as a being that extends throughout the whole of space. And this means that no creature can be spatially separated from God. The only sense in which creatures can be understood to be separated from God thus must have to do with the nature of their substance. And to differ from God with respect to substance presupposes that creatures are substances. This is why establishing the sense in which creatures can be understood to be substances is central for Taurellus’s project.