P31: We can have only an entirely inadequate knowledge of the duration of the singular things which are outside us.

Dem.: For each singular thing, like the human Body, must be determined by another singular thing to exist and produce effects in a certain and determinate way, and this again by another, and so to infinity (by IP28). But since (in P30) we have demonstrated from this common property of singular things that we have only a very inadequate knowledge of the duration of our Body, we shall have to draw the same conclusion concerning the duration of singular things {outside us}, viz. that we can have only a very inadequate knowledge of their duration, q.e.d.

Cor.: From this it follows that all particular things are contingent and corruptible. For we can have no adequate knowledge of their duration (by P31), and that is what we must understand by the contingency of things and the possibility of their corruption (see IP33 S1). For (by IP29) beyond that there is no contingency.