Analogy in St. Thomas

One of the first moves in explaining the doctrine of analogy in St. Thomas has been to point out that analogy is from the Greek idea of proportion or ratio. St. Thomas himself explains analogy by ratios, either as different ratios to the same thing (like 5/4 and 3/4, which has the technical name of “proper proportion” ) or the same ratio to different things (like 3/8 and 6/16 or “proportionality”).  The explanation works up to a point, but it leaves the main question of analogy open. Visualizing ratios between ideas allows us to see a way in which ideas can admit of both real equality and diversity, but Thomists are not interested in analogy in general but only so far as it helps us establish the unity of metaphysics and the attribution of positive names to God, and in neither case is it particularly satisfying to say that the various names involved are somehow the same and somehow different. This is the metaphysics of a confused teenager, i.e. “like, God and us are sorta the same but, like, not totally” or “substance and accident are both being, but they’re not like, ya’ know, being”.

St. Thomas is clear that the sorts of analogies he is interested in are the the ones where there is one thing signified (res significata) and diverse ways of signifying it (modus significandi). This is the precise way in which an analogous name, like equal ratios, can be both one and diverse. Notice STA says that there is only one thing signified. If you want to talk about existence or goodness, there is really just one thing there. There is one idea of existence, goodness, person, etc. and not a heap of loosely related analogous ideas. That said, we are not interested precisely in existence or goodness, but in the way in which these are, for example, predicated of God and human beings – and here is where one introduces a diversity. One can mean a single thing by “sews” but still not predicate it in the same way of the tailor and the needle; you can mean one thing by “choose” without having to say that means and ends are chosen in the same way; and likewise you can mean one thing by “exists” and not predicate it of God and creatures or substance and accident in the same way. This is just the way we deal with naming things that are arranged in causal orders: instruments and agents, subordinate and ultimate ends, essential and participated forms, etc, and the relation of God/creature and substance and accident is precisely such an order. God stands to creatures as a first mover to a secondary one, and so is described by the same sort of language we use to describe instrument/ agent relations (even if there are important differences) and substance is a subject for all other entities and so is as though the first in the order of material causality among definite things, and exists simply whereas other things exist secundum quid.

This is the “analogy” that STA was interested in. Notice that “ratios” can only get one started and can’t tell the whole story. What is chiefly involved here is a thing with a single meaning with essentially different predications.* This doesn’t exhaust all that STA means by analogous naming, but it touches on the main points.


I’m taking predicate not in a grammatical sense but in the sense where even adjectives and apposite nouns are predicates (they are prae-dicere, or “said of” something). We aren’t just talking about, for example, goodness as a grammatical predicate, as when we say “God is good” but also when we think about “the good and holy God” or speak of “the divine goodness”.


  1. socraticum said,

    July 26, 2013 at 12:21 am

    Do you have any thoughts about the difference between “modus significandi” as it is used in the debates about analogy and m.s. as the subject of grammar in, say, Martin of Denmark?

    • July 26, 2013 at 9:13 am

      My initial reaction – which is usually more extreme than my final one – is that they have no relation at all and that the the unity of name is pure coincidence. It seems impossible to me that St. Thomas meant modus significandi to be taken in a grammatical way since the grammatical modus significandi is identical in “God is good” and “man is good” (or, for that matter, in “evil is good” or “square circles are good”) whereas it is distinct in the account of analogy.

      The relevant distinction placed in the modus significandi here first turns up in a logical text (Posterior Analytics 1 c. 4-6, especially the chapter on the kath’ auto or per se) and in this sense is a logical distinction. In fact, it is a mode of logical as opposed to grammatical predication (the “composition and division” that is essential for the sort of truths a human mind makes). So if you need to give a one word answer to what science treats analogy, it’s “logic”. That said, the one word answer is going to leave out important things. Metaphysics uses logic in a particularly intimate way, and the sort of logic we are dealing with here is meant to reflect real layers or being and causal relationships, and in this sense analogy (and perseity) is metaphysical. But I can’t see any way in which it is grammatical.

      • socraticum said,

        July 26, 2013 at 9:45 am

        I agree that logic is the science which considers analogous names, but I’m not (yet) convinced that the double use of modus significandi is accidental.

        One, relatively superficial, objection is that modus significandi seems to be a technical term. As such, it would be odd for it to be equivocal merely by chance.

        Another objection is that, right at the beginning of the consideration of divine names in the Summa, St. Thomas raises the objection, no word can signify God because none of the modes of the parts of speech belong to God. (ST I.13.1.3) He answers this by showing the way in which the various parts of speech fittingly signify God.

        A further objection, is that the verb’s mode of signifying has significant implications for logic: future tense verbs produce statements that are neither true nor false. Consequently, the grammatical modi cannot be wholly accidental to the logician’s consideration.

      • July 26, 2013 at 10:33 am

        I don’t see the connection between the first objection and analogy – analogy doesn’t mean a single thing signified in different parts of speech.

        I’m very intrigued by the second objection – you could expand it to include an account of the importance of the moods of verbs (subjunctives express contingency, which is perhaps why there is no future subjunctive; imparatives imply order of action, etc.) and the difference between abstract and concrete nouns (which is one of the Thomistic ideas I return to most frequently, one whose consequences have yet to be adequately mined by theology). Still, I don’t see a connection to the idea of analogy yet.

        I tried on at least one occasion to explain modus significandi in a grammatical way, saying that the unity of analogy was from the thing apart from signification and the diversity was from the thing as signified (and thus the mode of contruction proper to a human mind). But I think this account is a dead end. It’s simpler to just take modus significandi as a generalization of the modus predicandi of APo 1 4-6. In this sense it is a technical term, but utterly distinct from the technical term that is divided into the seven (formal) parts of speech.

        One thing that is important here is that St. Thomas never shows much interest in analogy as such, and he gives no indication that one needs a taxonomy of analogy in order to do what he wants to do. In fact, such an account would probably take us too far afield and confuse the issue, since St. Thomas is interested in analogies that track causal subordination of two things and these are far from being the sort of analogues we are most familiar with, nor are they the most common sort of analogy. For example, we first understand analogies through diverse but related meanings of a single term in lexicons or dictionary entries (even the very philosophical ones, like Metaphysics V), but the analogies STA is interested in are not diverse in this way. There aren’t two dictionary entries for “cut”, with the first for the agent and the second for the instrument, though this is exactly the sort of analogy that we use in natural theology. St. Thomas does not make any philosophic use that I am aware of out of, say, the analogical meaning between “principle” as the edge of something and as any “from which”. He is aware that they are analogous, to be sure, but not in the sense of analogy that matters for natural theology or metaphysics.

  2. Matthew Livermore said,

    April 29, 2014 at 3:12 am

    Reblogged this on Philosophy of Religion and TOK and commented:
    A2 students – Aquinas on analogy

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