Thank you!

The contrapositive is something you’d apply in two ways: 1. If you drew a conditional statement, eg cats have tails, C -> T, then you could draw the contrapositive, ~T -> ~ C. Or you could do that in your head 2. More broadly, if there is a conditional statement, you can recognize the contrapositive is true, even if you don’t draw it. This is the most useful way to- ultimately you just want to know these things. Like if All airplanes have wings, then no airplane = no wings. That’s the contrapositive whether you draw it or not

Thanks! I'll have to make more. This was part of an abortive course on sufficient assumption questions I never quite finished. Good to see people are finding it!

Spent 2 grand on an lsat class and hundreds on prep books and this explained this concept better than either of those. Thanks

@@yalelaw I guarantee you haven't!

A nor would be this: A -> ~B and ~C. So contra positive is B or C -> ~A. Nor is just “not and”

Negating is just something you do as part of the contrapositive. Anytime you take the contrapositive, you reverse and negate. Negating isn't something you do in isolation. So like if I say "All cats have tails", we draw that in two ways: Cats --> tails contrapositive: no tail --> not a cat To fully understand the english sentence, you need to know it has both those forms. And if you have either form, to move to the other one you reverse the terms (swap cat and tail) and then negate them (tail becomes no tail, cat becomes not a cat) Hope that helps!