A R I S T O T LE ' S   S Y L L O G IS T I C   L O G I C

 

I. The 'usual' example of the 'Barbara' syllogism:

All men are mortal,
Socrates is a man,
therefore
Socrates is mortal.

II. Another (inference) form:

All men are mortal,
All Greeks are men,
therefore
  All Greeks are mortal.

III. The same, in the form of an implication:

If all men are mortal
    and all Greeks are men,
        then all Greeks are mortal.

IV. Generalized:

If all B is A
    and all C is B,
     then all C is A.

V. The actual Aristotelian syllogism:

If A is predicated of all B
   and B is predicated of all C,
    then A is predicated of all C.

A thorough discussion of Aristotle's logic may be found in:   Jan Lukasiewicz. Aristotle's Syllogistic from the Standpoint of Modern Formal Logic. Oxford, 1951.


rah.feb.99

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