LSAT Practice Test

When "All except Z are Y" is mentioned, what does it translate to in formal logic?

1. An evidence keyword

2. If ~Y --> Z

3. Negation

4. Necessity

The correct answer is: If ~Y --> Z

In formal logic, the statement "All except Z are Y" can be translated as "If something is not Y, then it must be Z." This translation captures the essence of the original statement where only Z does not fall under the category of Y. Therefore, option B, "If ~Y --> Z," is the correct translation for the given statement. Option A, an evidence keyword, is incorrect as the statement is not referring to evidence but rather about the relationship between Z and Y. Option C, negation, does not encompass the meaning of the original statement as it does not capture the conditional relationship between Y, Z, and other elements. Option D, necessity, also does not accurately represent the logic behind the statement "All except Z are Y."