If Center 3 recycles glass, then which one of the following kinds of material must Center 2 recycle?

Mohammad on December 2, 2016

Wood and Newsprint

Why isn't the converse true of "If a center recycles wood, then it also recycles newsprint". I watched the vids for the game set up and explanation of this question but I fail to understand why the opposite isn't true and why the answer to this question could not also be wood. Thanks.

1 Reply

Mehran on December 3, 2016

@varcity64 because the rules of Sufficient & Necessary tell us otherwise.

We can create the contrapositive of any S & N statement by reversing AND negating:

S ==> N
not N ==> not S

There are only two ways to validly apply a general principle:

(1) Invoke S to conclude N (postive argument structure)

(2) Negate N to conclude not S (contrapositive argument structure)

For you to take the existence of the necessary condition, in this case newsprint, to conclude the existence of the sufficient condition, in this case wood, would be flawed logic.

Remember, don't just reverse!

Hope this helps! For a more in-depth review of these concepts, please watch our video lesson on Sufficient & Necessary conditions.