P28: Every singular thing, or any thing which is finite and has a determinate existence, can neither exist nor be determined to produce an effect unless it is determined to exist and produce an effect by another cause, which is also finite and has a determinate existence; and again, this cause also can neither exist nor be determined to produce an effect unless it is determined to exist and produce an effect by another, which is also finite and has a determinate existence, and so on, to infinity.

Dem.: Whatever has been determined to exist and produce an effect has been so determined by God/Nature (by P26 and P24 C). But what is finite and has a determinate existence could not have been produced by the absolute nature of an attribute of God/Nature; for whatever follows from the absolute nature of an attribute of God/Nature is eternal and infinite (by P21). It had, therefore, to follow either from God/Nature or from an attribute of God/Nature insofar as it is considered to be affected by some mode. For there is nothing except substance and its modes (by A1, D3, and D5) and modes (by P25C) are nothing but affections of God/Nature’s attributes. But it also could not follow from God/Nature, or from an attribute of God/Nature, insofar as it is affected by a modification which is eternal and infinite (by P22). It had, therefore, to follow from, or be determined to exist and produce an effect by God/Nature or an attribute of God/Nature insofar as it is modified by a modification which is finite and has a determinate existence. This was the first thing to be proven.

And in turn, this cause, or this mode (by the same reasoning by which we have already demonstrated the first part of this proposition) had also to be determined by another, which is also finite and has a determinate existence; and again, this last (by the same reasoning) by another, and so always (by the same reasoning) to infinity, q.e.d.

Schol.: Since certain things had to be produced by God/Nature immediately, viz. those which follow necessarily from his absolute nature, and others (which nevertheless can neither be nor be conceived without God/Nature) had to be produced by the mediation of these first things, it follows:

I. That God/Nature is absolutely the proximate cause of the things produced immediately by him, and not {a proximate cause} in his own kind, as they say. For God/Nature’s effects can neither be nor be conceived without their cause (by P15 and P24 C).

II. That God/Nature cannot properly be called the remote cause of singular things, except perhaps so that we may distinguish them from those things that he has produced immediately, or rather, that follow from his absolute nature. For by a remote cause we understand one which is not conjoined in any way with its effect. But all things that are, are in God/Nature, and so depend on God/Nature that they can neither be nor be conceived without him.