Steelman
Illicit major
Also called illicit process of the major term.
The conclusion says something about all of a group that the premises only covered in part.
What it is
A categorical syllogism whose major term (the predicate of the conclusion) is distributed in the conclusion but not in the premise where it appears.
The pattern
All M are P. No S are M. Therefore, no S are P. (invalid)
An example
“All professional chefs can cook. No teenagers are professional chefs. Therefore, no teenagers can cook.”
“People who can cook” is a bigger group than professional chefs. Teenagers can be in it without being chefs.
Why it fails
The conclusion “No S are P” makes a claim about every P, but the premise “All M are P” only tells us about the Ps that are Ms. Other Ps outside M could still be S.
When it’s not a fallacy
Most lists skip this part. Calling a fair point a fallacy is a mistake too.
It can be fair when
- The major term is distributed in its premise, e.g. “No M are P. All S are M. Therefore, no S are P.” That form (Celarent) is valid.
Try one
A question from the app. The wrong answers are its usual look-alikes.
Family dinner. Uncle Ray: “Esports are a coin flip. Whoever’s internet holds up wins.” Priya: “Okay, anything won by luck is just a game. Agreed? But esports aren’t won by luck; the same pros win tournament after tournament, so it’s skill that decides them. So esports aren’t just games. I rest my case.”
What’s the flaw?
Priya’s first line says luck games are just games, not that every “just a game” runs on luck. Tic-tac-toe and Pictionary aren’t luck either, and they’re still just games, so being outside the luck games doesn’t put esports outside “just games”.
A fair reply
“Tic-tac-toe isn’t luck either, and it’s still just a game.”
Often confused with
- Illicit minor
Illicit minor makes the same error with the conclusion’s subject term instead of its predicate.
- Denying the antecedent
The propositional cousin: “If M then P; not M; so not P.”
Where the name comes from
The major term is the group named at the end of the conclusion, called its predicate. In “No teens are cooks,” it’s “cooks.” Illicit means not allowed. The conclusion makes a claim about every member of that group, but its premise only covered some of them. Illicit process of the major term is the longer, traditional name.
Sources
- Illicit Major, The Fallacy Files
- Syllogistic Fallacy (terminology and distribution), The Fallacy Files
In the app
Practice spotting it on arguments that sound real.
Steelman has more examples of illicit major, how to answer it in a real conversation, and practice rounds that mix it with its look-alikes, so you learn the difference, not just the name. Coming soon to iPhone and Android.
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