Quantifiers — All, Some, Most, None

All A are B: A → B. 100% of A have property B.

No A are B: A → not B. 0% overlap.

Some A are B: At least one A is B. Could be 1%, could be 100%.

Most A are B: More than 50% of A are B.

Key inferences:

All A are B + All B are C = All A are C (valid chain)

Most A are B + Most A are C = Some B are C (the overlap principle)

Some A are B does NOT mean Some B are A (it actually does — "some" is reversible)

Traps:

"All" does NOT mean "only." All dogs are animals ≠ all animals are dogs.

"Most" does NOT mean "all." Most students pass ≠ all students pass.

On the LSAT: Quantifier questions appear in LR and Logic Games. Precision matters — "some" and "most" are not interchangeable.

Reference:

Wikipedia: Quantifier

https://en.wikipedia.org/wiki/Quantifier_(logic)