3 ms·
Yes we can because if there are no ten-foot tall men, then it is indeed true that "All ten-foot tall men have brown hair"
by aidenn0 2y ago
Yes we can because if there are no ten-foot tall men, then it is indeed true that "All ten-foot tall men have brown hair"
- out_of_protocol 2y agoIf that is true then liar said truth.
- mr_mitm 2y agoIndeed, which is why the premise is false. So if a liar who always lies says that thing about ten foot men, ten foot men must exist, and at least one does not have brown hair.
- cafeinux 2y agoAnd that's why we must conclude that there must be a ten-foot tall man, so it can have non-brown hair, so that the liar indeed lied.
- out_of_protocol 2y agoWhy liar can't lie about ten-foot tall man? Liar could mean two-inch hamster but lied and said ten-foot tall man
- deleted 2y ago[deleted]
- aftbit 2y agoIt seems intuitively wrong that you can say "All X are Y" and yet that doesn't imply "At least one X exists".
- titzer 2y agoIt also seems intuitively wrong that there are different sizes of infinity, yet Cantor discovered exactly that.
- deleted 2y ago[deleted]
- scotty79 2y agoThat's how math defined what "all" means. You can be talking about all elements of empty set without implying it must have some. Basically it disentangled two unrelated concepts, that English language unduly mixes. Concept of every item having some quality and concepts of at least one item existing.
- njtransit 2y agoThat how we define "all" logically but not linguistically. For instance, linguistically we would consider this inconsistent: "all 10-foot men have black hair AND all 10-foot men have blonde hair" yet it is true, logically, if there are no 10-foot tall men. The translation of the English word "all" should be something something like: |Q| > 0 ∧ ∀x∈Q, x is ...
- spencerflem 2y agoIn formal logic, but in regular English that would not be true