Leibniz on substances’ expression of God

[Cross-posted from modsquad.]

Leibniz frequently uses the notion of expression. Expression is apparently a sort of representation relation. But what, according to Leibniz, has to happen for one thing to express another? Well, what often seems clear is the requirement that there be a regular relation between the expresser and the expressed. We might understand the debates in the secondary literature on this topic as largely about how exactly to understand Leibniz’s notion of a regular relation. There has been, for example, debate about whether expression is isomorphism. (See among others KulstadMatesSimmons, and Swoyer.)

The most discussed examples of expression are cases like an ellipse expressing a circle and a map expressing a piece of land. But Leibniz puts the notion of expression to a variety of other uses. Among them is his claim that some, or perhaps all, substances express God. Thus in the Discourse on Metaphysics we learn that “God’s Extraordinary Concourse Is Included in That Which Our Essence Expresses…” (DM 16 title); that “our soul … express[es] God and, with him, all possible and actual beings, just as an effect expresses its cause (DM 29); that “Minds Express God Rather Than the World, but That the Other Substances Express the World Rather Than God” (DM 35 title); and that “we may say that, although all substances express the whole universe, nevertheless the other substances express the world rather than God, while minds express God rather than the world” (DM 36).

This issue of the expression of God has been rather less discussed than expression in general. However in one relatively recent discussion, Alan Nelson says that “…spirits express God in virtue of being able to know eternal truths” (“Leibniz on Modality, Cognition, and Expression”, 284). That is, only some substances (spirits) express God. And they do this by being able to know eternal truths. In this post and a couple of following ones I want to consider both the suggested restriction to some substances, and the reasons why substances express God. I pay particular attention to the 1686 Discourse on Metaphysics.

A first question then: why, according to Leibniz, should we think that minds express God? Well, DM 16 tells us that “an effect always expresses its cause and God is the true cause of substances”. Given that, we can construct the following argument:

  1. An effect always expresses its cause.
  2. Every substance is an effect of God. So
  3. Every substance expresses God.

Similarly, Leibniz said — in some comments about expression in a letter written that year to Simon Foucher — that “Each effect expresses its cause, and the cause of each substance is the decision which God took to create it” (WFNS 53; A 2.2, p.91). That suggests a slight variant on the above argument:

  1. An effect always expresses its cause.
    2*. Every substance is an effect of God’s resolution to create it. So
    3* Every substance expresses God’s resolution to create it.

Despite some variation in exactly what is said to be expressed — which may not even be real disagreement, without a more detailed understanding of what it means to express God — we have very similar argument in both cases here. Substances express God, because God is their cause. Moreover, all substances do this, not just minds.

More posts to come on this: on why Leibniz thinks that substances express their causes; on the passages in the Discourse that distinguish minds from other substances; and on the extent, if any, to which Leibniz maintained this view over time.