Why Can You Call a Dog "Healthy" and a Diet Too?
A Girl, a Word, and a Medieval Mystery
At dinner you hear someone say, “This broccoli is healthy.” Later, they talk about a “healthy friendship.” Same word. But does it mean the exact same thing in both sentences? A human body and a friendship seem very different. If you thought about that for a moment, you were doing something medieval thinkers did for centuries.
Back in the 1200s and 1300s, scholars at the first universities — places like Paris and Oxford — were obsessed with how words hook on to the world. They didn’t just wonder about broccoli. They wondered: If we say God is good and a hamster is good, is “good” doing the same job? Their answers gave us tools we still use whenever we decide a word is being stretched, not swapped.
Signification: Words, Thoughts, and Things
Medieval logicians called the link between a word and what it stands for signification. A spoken term like “horse” is a sign: it makes your mind think of the concept horse, and it also points to actual horses out there. They thought concepts were natural — all humans with similar experience form the same idea of a horse without anyone deciding. But spoken words are conventional, born from an imposition: people agreed that certain sounds would go with certain things.
Thomas Aquinas (1225–1274) tackled a tricky part of this picture. When you say “horse,” do you mean the individual animals, or some shared “horseness” floating in between? He insisted there is no ghostly horseness. The term primarily signified the mind’s conception of horse, while the real nature (the property of being a horse) existed only in actual horses. The individual horse was the referent — the thing the word finally lands on.
This tidy triangle worked for everyday nouns. But what about words like “nothing,” “blindness,” or “every”? And what about words that seem to shift their meaning depending on what you’re talking about? That’s where the real fight began.
When One Word Means Many Things: “Healthy” Breaks the Rules
Aristotle (384–322 BCE) gave medieval thinkers their starting point. A univocal term has the same meaning across cases. “Animal” used of a human and an ox is univocal — one concept covers both. An equivocal term has completely different, unconnected meanings, like the word “pen” for a writing tool and an animal enclosure. No link.
But some words didn’t fit either box. The favourite medieval example was “healthy.” You can say a dog is healthy, its food is healthy, and its urine is healthy. Yet the food doesn’t have a pulse, and the urine isn’t lively. So it’s not univocal. But it’s not pure equivocal either — all the uses cluster around one central idea: health in the animal.
The early medieval scholar Boethius and later logicians called such terms analogical. They are used in a prior and posterior way. The animal’s health comes first; food is called healthy because it causes health, urine because it is a sign of health. The word keeps a family resemblance, not an identical copy. This gave thinkers a powerful third option beyond “same” and “completely different.”
Can God Be “Good”? Aquinas’s Analogical Leap
Now came a bolder puzzle. Medieval theologians believed God is utterly beyond us — not just a bigger version of a human, but a being whose goodness, wisdom, and existence are infinite and unshared. If we say “God is good” and “this child is good,” is the word univocal? That would make God seem too much like a creature. Is it purely equivocal? Then we could never say anything meaningful about God at all.
Aquinas argued that the divine names must be analogical. He rooted this in a picture of participation: God is goodness itself, and creatures only have goodness by sharing in it, like a fire shares heat. The relationship is a causal one — God’s goodness causes creaturely goodness, but the effect is never exactly like the unlimited cause.
Aquinas explored different flavours of analogy. In some works he leaned on analogy of attribution (cause–effect, much like “healthy” — the animal is the anchor). In others he turned to analogy of proportionality, comparing relationships: God’s goodness is to God as human goodness is to humans, even though the terms differ. He never landed on a single airtight formula, but his consistent move was this: “good” isn’t said in exactly the same way, yet the uses are related enough to let us speak and reason without falling into nonsense.
Duns Scotus Demands a Single Concept for “Being”
John Duns Scotus (c. 1266–1308) was not satisfied. He zeroed in on the word being. If “being” were purely analogical, how could you ever think about both God and a squirrel at the same time? You’d be trapped with two separate concepts that only looked related.
Scotus offered a now-famous test. Suppose you are certain that something is a being, but you don’t yet know whether it’s a substance or an accident — a rock or the rock’s colour. To hold that thought at all, he said, you must have a single unified concept of being that applies equally. If the concept split into two unrelated notions, you couldn’t be certain about that “something” without first knowing which kind it was. So being is univocal in logic.
He still agreed that in reality God and creatures are radically different — a metaphysical gap nothing bridges — but for our language and reasoning, univocity was the only way to avoid chaos. His challenge sparked centuries of argument: can a word carry a single concept while pointing to things that aren’t alike in any ordinary sense?
Why You Still Think Like a Medieval Logician Today
Whenever you say a movie is “smart,” a phone is “smart,” and your friend is “smart,” you’re doing what Aquinas and Scotus did. Are you using one sense stretched thin, or three quite different senses that just share a word? The medieval toolkit — equivocal, univocal, analogical — is still the most natural way to sort such questions.
Their debates also force us to ask: when we disagree about whether something is “good,” “fair,” or “real,” are we even talking about the same thing? A law might be fair in one way and a game in another, linked but not identical. Medieval thinkers trained themselves to notice those shifts, and you can too. Next time you hear “that’s so unfair,” you might stop and wonder: is that “unfair” being used univocally, or are there different anchor points tugging at the word? That’s not just history — it’s philosophy happening in your own head.
Think about it
- If your friend says “That joke is cold” and your dad says “This soup is cold,” are they using “cold” in the same sense? What would Aquinas and Scotus each say?
- Can you think of a word you use for both a person and a video game that might be analogical? Where is the anchor — the central meaning — in your example?
- Do you believe there can be one perfect definition of “good” that covers pizza, helping a friend, and a beautiful sunset? Why might someone answer no?
