Where the syllogism "All men are mortal / Socrates is a man / Therefore, Socrates is mortal" first appeared?

  • Did you notice that later in the article, making it part of the conclusion, the author uses the expression “identical to Socrates”? I can say that the expression is redundant because “The only thing identical to Socrates is Socrates.” Law of Identity, A is A, Aristotle.
    – user48454
    Sep 23, 2020 at 15:09

2 Answers 2


Comment on similar example.

The example is not from Aristotle.

Categorical propositions with singular terms are used in Medieval logic; see Peter of Spain's Summulae logicales (XIII century):

I,8 Propositio singularis est illa [...], ut "Sortes currit" [Socrates runs].

Into this textbook we can find many examples of them in the discussion of loci and entimema [V,3], bt it seems to me that there is no occurrence of the specific example of syllogism.

According to: Joseph Maria Bochenski, A History of Formal Logic (1961, or.ed.1956), page 232:

A first widening of the Aristotelian syllogistic consists in the admission of singular terms and premisses. William of Ockham (c.1287–1347) already knows of the substitution that was to become classic [Summa Logicae, III 1,3;36rb]:

Every man is an animal;

Socrates is a man;

Therefore, Socrates is an animal.

Here the minor premiss is singular. But Ockham also allows singular propositions as major premisses.

The earliest occurrence I've found is:

Socrates is human.

Everything human is an animal.

Therefore, Socrates is an animal.


Per David A. Wheeler's article "The Origin of All Men are Mortal" (which elsewhere cites this page!)

The earliest document I can find with this specific example is from 1843, specifically A System of logic: Ratiocinative and Inductive, Presenting a Connected View of the Principles of Evidence and the Methods of Scientific Investigation by John Stuart Mill, 1843, Book II Chapter 3 page 245.

One can indeed see the quote

2. It must be granted that in every syllogism, considered as an argument
to prove the conclusion, there is a petitio principii. When we say,

All men are mortal
Socrates is a man
Socrates is mortal ;

it is unanswerably urged by the adversaries of the syllogistic theory,
that the proposition, Socrates is mortal, is presupposed in the more
general assumption, All men are mortal:

in the Internet Archive's copy of Mill's System of Logic.

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