SOLUTION: Prove that the following argument is not valid. "If it rains, crops will be good" if it did not rain, therefore, crops were not good.

Algebra ->  Conjunction -> SOLUTION: Prove that the following argument is not valid. "If it rains, crops will be good" if it did not rain, therefore, crops were not good.      Log On


   



Question 569541: Prove that the following argument is not valid. "If it rains, crops will be good" if it did not rain, therefore, crops were not good.
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
I haven't taken formal logic, but it is possible that crops will be good even if it doesn't rain. This is like saying "If a quadrilateral is a square, it is a rectangle." However, the obverse "If a quadrilateral is a rectangle, it is a square" is not always true. It is true if and only if the relation is one-to-one.

However, the contrapositive is always true and equivalent to the original statement: "If crops are not good, it did not rain."