I would like to learn about theory of supposition. Can you recommend any good books/video/etc about it?

Question

I encountered following syllogism as an example of false equitation:

Man is a species

Socrates is a man

Therefore, Socrates is a species

The text ("An Introduction to Traditional Logic" by Scott M. Sullivan") also noticed that fallacy occurs due to change of supposition. Namely, "The major uses “man” with simple supposition while the minor uses the same term with personal supposition and so the inference is fallacious.". As far as I can tell, the author uses concept of "supposition" developed by medieval scholastic logicians. Supposedly this theory explains what is wrong with syllogisms like this. The text contains explanation for theory of supposition (in appendix article "In Defense of the Square of Opposition"), but I wasn't able to understand it. I would like to get alternative sources for introduction to the concept of supposition. Preferably not overly obscure or created only for professionals. Any help?

Answer 1

See Medieval Theories: Properties of Terms as well as William of Ockham: Signification, Connotation, Supposition for a good overview.

In a nutshell supposition (according to Medieval philosophy) is the relation between a term (name, etc) and what that term was being used to talk about (the referent of the term).

Thus, the name "Socrates" is in relation of supposition with the philosopher Socrates. –

"Medieval logicians divided supposition into many different kinds; the jargons for the different kinds, their relations and what they all mean get complex, and differ greatly from logician to logician. The most important division is probably between material, simple, personal, and improper supposition. A term supposits materially when it is used to stand in for an utterance or inscription, rather than for what it signifies. Simple supposition happens when the term is standing in for a human concept rather than for the object itself (the "man" case). Personal supposition in contrast is when the term supposits for what it signifies (the object: Socrates).

Answer 2

I encountered following syllogism as an example of false equitation: [...]

a set-theoretically-minded rendering probably should look like

'(hu)man' ∈ 'species'

'socrates' ∈ '(hu)man'

so that " 'socrates' ∈ 'species' " simply does not to follow

The text ("An Introduction to Traditional Logic" by Scott M. Sullivan") also noticed that fallacy occurs due to change of supposition. Namely, "The major uses “man” with simple supposition while the minor [...]

this stuff is outdated

Any help?

forget about it, learn something more current, like set theory or type theory