 Another, more circuitous option begins with a functional account of modes in Spinoza’s ontology. The function of modes, according to passages like Ip25c, is to provide ways of expressing or conceiving the power of substance. Perhaps Spinoza actually provides an analysis of inherence in terms of this expressive or conceptual relation, similar to the way in which he provides an analysis of causation in terms of conceptual connection. Consider, for instance, Id3, in which Spinoza defines substance as that which is “[a] in itself and [b] is conceived through itself, that is, [c] that whose concept does not require the concept of another thing from which it must be formed” (the brackets are mine). Instead of leaving inherence as an unprincipled primitive relation of metaphysical dependence (pace the PSR), one could read [c] as providing an analysis of both [a] and [b]. One thing inheres in another in virtue of being conceived through it, which, like causation, is a matter of conceptual involvement. That everyday objects are modes inhering in and predicated of substance is extensionally and intensionally equivalent to everyday objects being conceived through substance. Whereas Curley’s interpretation took causation to be Spinoza’s underlying account of inherence, this interpretation takes conceptual involvement to be Spinoza’s underlying account of both inherence and causation (for a recent defense, see Newlands 2010a; for dissents, see DiPoppa 2013, Melamed 2012 and Laerke 2011).