 Pace Spinoza, the claim at IIIp4 that no thing can be destroyed except through an external cause is not clearly self-evident. Even assuming IIIp4 to be true, however, one might raise questions about Spinoza’s argument. Why is it that, just because a thing does not strive to destroy itself, that thing must therefore strive to persevere in being? A thing might, it seems, not strive for anything, or perhaps it might strive to do something which is neither perseverance nor self-destruction. Spinoza’s use of IP34 and Ip25c seems intended to rule out the first of these possibilities. Although Spinoza’s term ‘express’ (exprimere) is notoriously unclear, it may mean something like “is a particular form of.” In that case, because particular things are expressions of God’s essence, his power, they must be particular forms of power. So there cannot be a thing which does not strive at all or, in other words, there cannot be a thing which is not any expression of power at all.