Thread: Another, "If A happens, then B happens"

Again, I am unsure about this one because it seems to be very poorly phrased in terms of grammar. I believe the answer should be VALID, it's just not phrased correctly?

In any event, any help or feedback would be greatly appreciated.

"IF A HAPPENS, THEN B HAPPENS.
B DOES NOT HAPPEN.
THEREFORE A DOES NOT HAPPEN."
[valid/invalid why]?

Originally Posted by pleasehelpme12345

Again, I am unsure about this one because it seems to be very poorly phrased in terms of grammar. I believe the answer should be VALID, it's just not phrased correctly?

In any event, any help or feedback would be greatly appreciated.

"IF A HAPPENS, THEN B HAPPENS.
B DOES NOT HAPPEN.
THEREFORE A DOES NOT HAPPEN."
[valid/invalid why]?

This is the contrapositive of the statement. The contraposative is logiacally equivelent to the original.

If a then b is the same as if not b then not a

Originally Posted by pleasehelpme12345

Again, I am unsure about this one because it seems to be very poorly phrased in terms of grammar. I believe the answer should be VALID, it's just not phrased correctly?

In any event, any help or feedback would be greatly appreciated.

"IF A HAPPENS, THEN B HAPPENS.
B DOES NOT HAPPEN.
THEREFORE A DOES NOT HAPPEN."
[valid/invalid why]?

I gave you the validation in your last post. This is an example of a statement and its contrapositive. If the statement is true, then the contrapositive is true. Look at the other post. And look here: Logic - Contrapositive