A definition and division of analogy

Aristotle’s metaphysics is grounded on analogy, that is, on a single term with many meanings. We encounter difficulties with the notion of analogy from the moment we define it: for how can one term have many meanings? What is there to “being one term” except “having one meaning”? But an analogous term is truly a single term, and it can be distinguished into at least six species.

It is important to insist at the outset that the many meanings of an analogous term are equivocal, but they have an additional feature: the meanings of the term are such that one meaning cannot be understood, or cannot be understood well, without understanding another meaning. The equivocal meanings are only the genus of an analogical term: the necessity of understanding a later meaning in relation to an earlier one is the specific difference.

When a term has many meanings, sometimes the meanings must be understood in a distinct order. If we wanted to explain what the word “light” meant, we wouldn’t begin by saying “that in virtue of which the conclusion of an argument is known” even though this is exactly what “light” means in the sentence “let’s understand this in light of the historical circumstances”. Neither would we say “the divine compenetration and emanation between Trinitarian persons, as defined in the fourth century” even though this is what the word “light” means when it is used in the Nicene Creed. The first explanation of the word “light” is much different: we do something like go over to a light switch and flick it on and off while saying “light…dark…light…dark”. We first understand a root meaning of the term which is close to sensation, and we can then use it as a principle to understand later meanings of the term. We simply cannot understand all the meanings of “light” in any order we please. The union of the later meanings to the earlier meanings make the two meanings inseparable, which justifies calling analogues a single term.

We must immediately distinguish analogues from two very different things: metaphors and terms that are analogous by accident. The former do not have the same genus as analogy; the latter do not have the same specific difference.

Analogy is not metaphor because metaphors do not involve equivocation. If one wants to explain the metaphorical word “shadow” in Macbeth’s famous line “life is but a walking shadow”, he gives exactly the same explanation he would give of the word “shadow” under normal circumstances. Macbeth means to signify a shadow, but he places this signification next to “life” and identifies the two. The power of the image is precisely because he is using the word “shadow” in its first, concrete meaning.

Just as metaphors are like analogies that lack the same genus, terms analogous by accident are very much like analogues, but they have the specific difference only accidentally and not by nature. In accidental analogy, we give a term a new meaning even though we can understand the second meaning without reference to the first. The word “red” meaning “communist” is a good example. Clearly, the word “red” existed before communism and we named the latter from the former, but a failure to understand the first meaning of the word “red” wouldn’t harm our ability to understand what communism is. A man blind from birth could understand the works of Karl Marx just as well as anyone else. One is no worse a teacher for forgetting to show students the color red before explaining communism; one is just as knowable as the other regardless of which one we happen to know first. Even if all the speakers of some language happen to know one meaning of a term before another meaning, this is not enough to call the terms analogous per se. Real analogy does not follow from a consideration of the order of terms in a language, but from a consideration of the order in which the terms must be understood.

Again, when we see that analogy as such is constituted by later meanings of a term requiring earlier meanings to be understood, we see the answer to our initial question “If there are two meanings of an analogous term, how can we call it one term?” Focus on the later analogue. Later analogues have only one meaning, but the meaning is such that it cannot be understood apart from the earlier meaning. The later term cannot be a term at all without an actual reference to an earlier meaning, for without this earlier meaning the term simply cannot function as a term at all, for it cannot generate knowledge in us.

The basic words in a language are usually real, per se analogical terms. Words like big, small, high, low, weak, strong, in, around, before, motion, come, go all have basic sensible meanings that unavoidably extend to include new meanings. The first meanings are known immediately and the later ones known only in reference to them. For example, we can understand something about a small mind by considering a small box or a cold heart by imagining a cold day, but not vice versa.

Languages frequently have analogous terms which have been cut off from their root meanings. This is particularly true of Romance languages, where certain analogous terms entered the language in their later meanings and then became isolated and cut off from their roots in Latin. Consider the word “concept”. For a native Latin speaker, the word “concept-us, a, um” sounds like “grabbed”, and if one brings out the “con” prefix, it sounds like “grabbed with”. In later Latin, the word came to mean exactly what it now means in English, but a Latin speaker could hear the analogical root when he used the term. For the English speaker, however, the word “concept” calls forth nothing from the imagination. The English speaker does not have access to what the Latin speaker had, namely an ability to understand the act of the mind by the act of a net, a hook, or a hand. But it is better to understand the action of the mind by understanding it through the action of hooks, nets, and hands- and a sign of this that English speakers use the word “grasp” to describe what the mind does. The Latin word concept-us, therefore, followed the order of knowing in a way that the English “concept” does not. When speaking of “concepts” the English speaker always runs the risk of talking about something he doesn’t understand, or at least that he doesn’t understand as well as he ought. The same could be said of the other Latinate and Hellenic words that are critical to the enquiry here: substance, matter, method, nature, physical, etc.

Because the order of analogues follows the order of knowing, the division of analogues follows the divisions in the order of knowing. Though we will not claim to have exhausted all the possible divisions in the order of knowing here, we will lay out six of them that are useful for our purposes.

The First Species of Analogy
Naming the Less Knowable Whole by the more Knowable Part

We frequently go from understanding a more knowable part to understanding the class of things of which it is a part. The first way we use the word “animal” does not usually include human beings or insects, but later on we let the term expand to include all animals simply. However, we still keep the old meaning of the term and make use of it, as in the phrase “animal rights”. Similarly, the species of bird “cardinal” was named from the male of the species, which is bright red, but the name was extended to include the female of the species also, which are harder to spot and more difficult to classify by simple observation. In general, it is common in taxonomy for animal species to take their name from the sex that is easier to know.

Second Species of Analogy
From the More Generally Known Whole to the More Distinctive Part

Another kind of analogy occurs when we make analogues by moving from a meaning that applies to a general whole to a meaning that applies to a more restricted part. Students of Aristotle first encounter this kind of analogy in chapter eight of the Categories, when Aristotle first speaks of “disposition” as referring to both habit and disposition, and then later on he restricts the word disposition to mean only those dispositions that do not last long. Similarly, the word “species” first of all applies to any similar class of things, and in this vague sense we can speak of dogs being a different species from cows, but a more refined scientific account insists that dogs are in fact a sub-species as opposed to a species.

Third Species of Analogy
From the Defined Whole to the Formal Part

Another way of moving from a whole to a part involves moving not from a general whole to a more precise part, but from a defined whole to a formal part. In any definition, the formal part is more significant and intelligible, which allows it to be in some way separated from its genus an applied to another genus. St. Thomas uses this kind of analogy when discussion how God can have “passions”. “There are some passions which, although they do not befit God as passions, nevertheless in the nature of their species they do not bring in the idea of anything contrary to the divine perfection.” One can speak of God having “delight” or “joy” only if he removes the more intelligible formal part of the word from its generic, bodily substratum. The same sort of analogy can apply to times when we move from a higher genus to a lower one. When we go from saying that men, plants and animals “grow” to saying that investments “grow” we move from a higher genus (the living) to a lower one (the inanimate).

Fourth Species of Analogy
One Proportion between Two Things

We also move from one term to another by seeing how the things named fit together. For example, things often take their name from their distinctive or proper operations a hammer hammers, a saw saws, etc.

This kind of analogy is most useful when we move from an effect to a more known cause, or otherwise go from something outward and more sensible to something inward and more intelligible. Now in all kinds of analogy there is some motion toward the more intelligible, to be sure, but with this fourth kind of analogy we see for the first time a move towards the more intelligible based upon proportion. An effect stands to its cause and somehow “fits together” with it; just as an operation fits with the source of operation, or the way an instrument fits with its principal agent, or the way the measure fits together with the measured, etc. This proportional naming is the first sort of naming that can be called “analogous” in the first and proper sense of the term “analogy”.

The Fifth and Sixth Species of Analogy,
Multiple Proportions between Things

Given that there can be proportions between meanings of terms and the things they signify; there can also be comparisons of proportions. The simplest such comparison is when two things compare in different ways to some one thing. Said another way, we perceive that some proportions have a “common denominator” tying them together and giving them unity through a common measure. This is the well known analogy of proper proportion. Medieval commentators always spoke of this sort of analogy by comparing how “healthy urine” and “healthy medicine” were both said in relation to the “common denominator” of a healthy animal.

Even if two proportions do not have a common measure, they can still have a unity by standing in the same way to different things. This is the well known analogy of proportionality. This sort of analogy is used for all things that do not share a common genus: e.g. “light” said of the action of a florescent bulb, and the human mind.


  1. Peter said,

    June 9, 2009 at 5:05 am

    D. Berquist has a text up — a recent addition, I think — on the “name equivocal by reason.” “Check it out.

  2. T. Chan said,

    June 9, 2009 at 1:38 pm

    The links in the second post work fine.

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