Venn diagrams Flashcards
We shade…
where we know nothing exists
We place an x…
where we know something exists
Universal assertion
All S are P
Particular assertion
Some S are P
Universal denial
No S are P
Particular denial
Some S are not P
Categorical proposition
proposition that either asserts or denies that all or some members of a category are included in another.
Contraries
Do not exhaust logical space. Universal assertions are contrary to universal denials. They cannot both be true, but they can both be false. e.g. all bread it nutritious, no bread is nutritious
Contradictories
Do exhaust logical space. Universal assertions are contradictory to particular denials. e.g. all bread is nutritious, some bread is not nutritious
the universal premise should always be diagrammed…
first
if the x can go in two regions, put it…
on the line in between
