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Bearistotle's wisdom (lemmy.world)

submitted 1 week ago by [email protected] to c/[email protected]

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[–] [email protected] 4 points 1 week ago* (last edited 1 week ago) (1 children)

Syllogisms ignore whether each premise is factually true. It focuses on whether it is internally coherent.

If I said:

All peanut butter are cats.
Some peanut butter are dogs.
Therefore: Some cats are dogs.

It would be a valid syllogism (structurally valid). This would mean the premises must be evaluated.

You can test yourself on syllogisms here.

You'll inherently understand what I'm saying after a few rounds.

[–] [email protected] 5 points 1 week ago* (last edited 1 week ago) (1 children)

Your example is incorrect.

All cats are peanut butter (c is a subset of p)
some peanut butter are dogs (p intersects d, or, d is a subset of p)
some cats are dogs (c and d intersect, or, d is a subset of c)

The first two do not make the third.

You can have:

c is a subset of p,
d and p intersect,
The section of p that intersects with d does not contain any c

To fix this, reverse the first statement.

All peanut butter are cats (p is a subset of c)
some peanut butter are dogs (p intersects d, or, d is a subset of p)
some cats are dogs (c and d intersect, or, d is a subset of c)

Any portion of d that intersects with p (some p is d) must also be c (since all p is in c). Hence some c, but not all c, is in the portion of p that intersects with d (some c is d).

[–] [email protected] 3 points 1 week ago* (last edited 1 week ago)

Oops. I fucked up lol. I changed it with your edit :p

Mental note: don't do syllogisms at 1am.