1

I wonder if this is true for all deductive arguments,

a deductive argument must have at least one premise where the term "ALL" or "NONE" or an equivalent word appears

Is it true? Can anyone show any counterexample?

NB: By equivalent I meant word or semantics. For example, "Every" can be used instead of "All" etc.

10
  • 1
    "or equivalence"? what does it mean? Jan 10, 2021 at 18:59
  • 1
    If you refer to Aristotle's Syllogism the answer is YES. No valid deduction with only particular premises. Jan 10, 2021 at 19:01
  • by equivalence i meant word or semantics. For example, "Every" can be used instead of "All". . etc. @MauroALLEGRANZA Jan 10, 2021 at 19:01
  • 6
    On the other hand, if you are referring to anything other than Aristotle's syllogisms, then the answer is no. Mike is a mechanic; therefore somebody is a mechanic. My next door neighbour has a cat and a dog; therefore my next door neighbour has a cat. The card up my sleeve is an ace or a king; it is not a king; therefore, it is an ace. Etc.
    – Bumble
    Jan 10, 2021 at 19:31
  • 1
    I had not realized it, but you are correct. Every valid syllogism contains at least one premise which is an A statement (All X are Y) or an E statement (No X are Y). Thank you. Jan 11, 2021 at 3:12

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.