Are you sure this is a correct example of the scientific method:
If it's raining then the roof is wet.
The roof is wet.
Therefore it's raining.
Shouldn't it be something more like this:
Observation: Rain makes my driveway wet.
Hypothesis: Rain makes all things wet.
Prediction: Rain will make my roof wet.
You can test this prediction.
In other words, this may not be a correct reduction of the scientific method to logic:
Premise 1 If A, then B
Premise 2 B.
Conclusion Therefore A.
I think what you've actually attempted to address is the logic for reasoning backward to original causes, and you're absolutely right that the logic you've provided is false, but it would be a poor scientist who forgot that any effect can have more than one cause. Putting it in terms of your rain analogy, there's more than one way for a roof to get wet, and everyone understands that rain is only a likely candidate, not an unavoidable conclusion.
-- | Percy |
| EvC Forum Director |