Why is affirming the consequent invalid?
Affirming the consequent is invalid because it assumes a specific cause for an outcome that can have multiple causes. Consider the formula for affirming the consequent:
- If P, then Q.
- Q.
- Therefore, P.
The above syllogism is fallacious because Q can be true for reasons other than P. The mistake lies in assuming a single cause for an effect or trait.
For example:
- If a number is a perfect square, then it is positive.
- The number 14 is positive.
- Therefore, the number 14 is a perfect square.