Every Time You Say "Man", Who Do You Mean?
The Dodo Trap: When Your Words Play Tricks
Around 1240, a young scholar in Oxford might have chewed on a strange little argument. Suppose you say “A dodo lived.” That’s true—dodos really did roam the earth centuries ago. Now try “A dodo lives.” False. There are no dodos alive today. Yet if you start only with “A dodo lived,” you might think it’s fine to switch to “A dodo lives.” Something went wrong, but the words didn’t change their dictionary meanings. The word “dodo” itself didn’t become a different word. So what slipped?
A teacher named William of Sherwood (writing in the 1240s) would have smiled. He knew that the same word can stand for different things in different sentences, especially when a verb like “lived” shoves its reach backward in time. To avoid silly mistakes, you need to track exactly what a word is pointing to on each occasion. That tracking project became one of the great achievements of medieval philosophy: the theory of the properties of terms. Over the next four centuries, logicians like William, Peter of Spain, Lambert of Auxerre, William of Ockham, Walter Burley, and John Buridan built a toolbox for examining how words hook onto the world.
Signification: A Word’s Permanent Face
Before a word ever enters a sentence, it has a core job. Medieval logicians called this signification. A word’s signification is what it brings to mind on its own, independent of any particular use. If you hear the word “man,” you grasp something about humanity—whether you’re talking about Socrates, a crowd, or a grammar book. As Lambert of Auxerre (fl. 1250s) put it, signification is “prior to supposition.” It is the foundation; all the other properties depend on it.
But what exactly does a word signify? Here the medievals split. Many, following a realist tradition, believed that “man” signifies a universal form—humanity itself, something shared by all individual people. For someone like Walter Burley (c. 1275–1344), the term points to that second substance. That is why you can say “Man is a species.”
William of Ockham (c. 1287–1347) disagreed sharply. As a nominalist, he thought universals were just words or mental acts, not real shared entities. For Ockham, “man” does not signify a ghostly form. It signifies all the individual men—Plato, Socrates, you, every person. Signification, for him, was simply the class of things the word can truly be said of. In either case, signification stays constant. The moment a word pops up in a sentence, though, a new property takes over.
Supposition: The Great Switching Game
Once a term slides into a proposition, we need to know what it supposits for—what it stands for in that particular claim. The medievals called this supposition, and they sliced it into three big kinds.
Material supposition happens when a term stands for itself as a piece of language. “Man is a noun” or “Man has four letters” uses “man” to point at the word, not at any person. You’re talking about ink and sounds. Simple supposition occurs when the term stands for the universal or concept it signifies. “Man is a species” doesn’t talk about any one person; it talks about the type. Personal supposition is the everyday case: “Socrates is a man” uses “man” to pick out a real, breathing individual.
These aren’t just labels. Confusing them leads straight into logical potholes. Look at this argument:
- Man is the worthiest of creatures.
- Socrates is a man.
- Therefore, Socrates is the worthiest of creatures.
Both premises can be true, but the conclusion is false. Where’s the trap? In premise 1, “man” has simple supposition—it speaks of the kind. In premise 2, “man” has personal supposition—it speaks of a single guy. So there’s no single middle term to glue the premises together. The same word is doing two different jobs. William of Sherwood called such mistakes fallacies of univocation: the signification stays the same, but the supposition shifts out from under you.
How do you know which kind of supposition is at work? The medievals had a rule: “subjects are such as predicates permit.” If the predicate is “is a species,” you’d better take the subject simply. If it’s “is running,” you’d take it personally. By the fourteenth century, many logicians decided that a term should be assumed to have personal supposition unless a special marker—like “this term” or the funny word ly—signalled a material use.
When Time Stretches Words: Ampliation and Restriction
The dodo puzzle already showed that tense verbs mess with supposition. A verb in the past tense, the medievals said, ampliates (widens) the subject so it covers not just present things but past ones too. “A dodo lived” makes “dodo” reach into history. Adjectives can do the opposite: “white horse” restricts “horse” to only those that are white. Most logicians treated ampliation and restriction as standard features of supposition.
Then Ockham came along and stirred the pot. Take a sentence like “A white thing was black.” Standard ampliation theory said this means: something that is white or was white was black. That treats the subject as disjunctive—stretching over two stretches of time. But Ockham thought that was sloppy. He insisted the sentence is genuinely ambiguous, not simply widened. It might mean “What is white was black” (true if a swan now white was once black) or “What was white was black” (true if something white in the past turned black later). For Ockham, you have to disambiguate—you can’t just lump them together.
His sex-change example makes the point unforgettable. Suppose, for the very first time in history, a person who was a woman becomes a man. The sentence “A woman was a man” is true if we read it as “A person who is now a man was a woman.” But it’s false if we read it as “A person who was a woman was a man”—because no one who was a woman had ever also been a man at the same time. The ampliative theory, with its disjunctive “what is or was,” would say the whole sentence is true just because one of the two disjuncts is true. Ockham said that flattens a real difference. The sentence has two distinct senses, and we must keep them apart.
Modal verbs like “can” and “must” create similar tangles. “A white thing can be black” may sound true, but Ockham noted ambiguity. In one sense, it’s false—nothing can be white and black simultaneously. In another sense, it’s true because something white now could turn black later. Ampliative accounts risk blurring these lines, so careful logicians had to decide whether a term was genuinely ampliated or whether a sharp-eyed ambiguity analysis was better.
Pronouns and the Hooded Man: Even Finer Points
The medieval toolbox also included relation (the behavior of anaphoric pronouns) and appellation (the present-tense applicability of a predicate). Both show that tiny shifts in wording can change what a whole sentence commits to.
Take a relative pronoun like “himself.” In “Every man sees himself,” “himself” clearly doesn’t just copy the word “man” or “every man.” If it did, the sentence would mean “Every man sees every man,” which is obviously different. The medieval rule said that the relative keeps the same supposition as its antecedent, but often in a disguised way. In this case, “himself” forces a distributive reading: each man sees his own self, singularly. You can’t just swap the antecedent word back in without changing the logical structure.
Appellation, meanwhile, spotlighted the predicate’s need to be truly predicable now of the subject’s supposita. This explained a famous puzzle from Aristotle, the “hooded man” fallacy. Suppose you know Socrates well, but you don’t recognize him as he approaches wearing a hood. The sentence “You know Socrates approaching” is false, because the predicate “know Socrates approaching” would need to be true of you right now—and you don’t know that it’s him. Yet “Socrates approaching you know” can be true; here, “him you know” points to Socrates under some concept, and you do know him. The word order and what gets appellated flip the truth-value. John Buridan (c. 1300–1358) refined this insight by showing that certain verbs make predicates appelllate their very rationes—the concepts by which we grasp them—so whether you know the person under that description becomes decisive.
Why Medieval Word‑Detectives Still Matter
At first glance, these medieval distinctions can feel fussy. But they track something deeply human. Every time you say “I called my mom,” you might be using “mom” to pick out your actual mother (personal supposition), or you might be checking a spelling: “I wrote ‘mom’ with two m’s” (material supposition). The difference is rarely confusing because you are already a natural-born supposition‑hunter. The medievals just gave the rules a name.
Computer programming, legal arguments, and everyday misunderstandings all crumble when a word’s reference isn’t pinned down. “If the park closes at dusk, you’re not allowed inside.” Does “the park” mean the physical land, or the legal entity? Does “dusk” mean a fixed time or whenever it looks dark? Sorting that out is twenty-first-century supposition theory in action. The fourteenth-century logicians didn’t solve every puzzle, but they built a vocabulary and a habit of mind. They showed that language is a tool whose pieces lock together in precise ways—and that with the right distinctions, you can stop words from playing tricks on you.
Think about it
- If you say “My favorite animal is a cat,” does the word “cat” stand for your specific pet, the whole feline species, or the letters C-A-T? Can you construct a real conversation where the answer matters?
- Think of the sentence “I just saw it.” How many different things could “it” refer to in one day? Would the medieval rule “subjects are such as predicates permit” help you figure out the intended meaning?
- Imagine a time‑travel story where someone says “I met a real dinosaur.” According to a medieval ampliative approach, does “dinosaur” automatically stretch to include any creature that ever existed? Or does Ockham’s ambiguity idea force you to ask two separate questions first?
