Lawgic at Odds with Formal Logic?

nmmizokami

I've taken some formal logic classes in the past and am familiar with some of the rules they use. I've really been struggling with parallel reasoning questions so I've returned to studying valid categorical syllogisms. Long story short, I've encountered some areas in formal logic which seem to contradict the lawgic lessons of 7sage.

For example, universal negative propositions (No S is P) can be diagrammed in lawgic S ---> ~P. This form of diagramming and the 7sage lessons imply that P ---> ~S is a valid inference (contraposition). In formal logic, however, this is not a valid form of contraposition. You can contrapose No S is P to infer that some non-P is not non-S (with limitation).

I don't mean to get this deep into formal logic but this contradiction is apparent from even a shallow review of valid syllogism forms.

Am I missing something? Or are there areas on the LSAT that do not conform to formal Aristotelian/Boolean logic?

Is there anyone else that has studied formal logic deeply and successfully applied it to the LSAT?

ebalde1234

From what I’ve read lawgic is not the same as logic. Don’t confuse the two . There may be similarities but looking at through that lense looks like it’s confusing you. Use it in the same way jy does