Although I can see that the positivist view of science (it works, therefore it works) has its merits, I think the Popperian ideal of falsifiability provides some insurance of applicable congruity between theory and observed results that the purely practical positivist approach lacks.
Karl Popper wasn't saying that it has to be wrong to be right, he was merely saying that if you come up with a theory then you should be able to make predications based on your theory. If your predictions fail then you should look for another theory. This is "safer" than saying "I have observed an outcome and since my theory appears to fit what happened, my theory must be true".
Popperian proof is known as modus tolens. Positivists, on the other hand, use the approach known as modus ponens.
The two can be described a bit like this: For modus ponens your reasoning would go:
"If Faldage is a man, then Faldage is mortal.
Faldage is a man.
Therefore Faldage is mortal."
There is no necessary congruity between the assertion that Faldage is a man and the assertion that Faldage is mortal. How do you know that all men are mortal? You haven't observed every man, so you can't "prove" that all men are mortal.
Modus tolens, the Popperian (and Baconian) approach, is a twist on this:
"If Faldage is a god, then Faldage is immortal.
Faldage is not immortal
Therefore Faldage is not a god."
In this case, you have asserted that if Faldage is a god, then by definition he must be immortal. Faldage disobligingly proves he isn't mortal, so you therefore have incontrovertible proof that he is not a god.
Popper put it like this:
"If the theory is true, then the prediction is true.
The prediction is not true.
Therefore the theory is not true."
I pinched these examples - you have no idea how famous Faldage isn't - from my philosophy of science textbook from yonks back, but they should serve to show the positivists such as Dr Bill that modus tolens is in no way inconsistent with his own philosophy. It is, if anything, merely a safer approach to the verification of a theory through falsifiability than pure positivism is.
If you're interested in following this up (and I warn you, it's just a tad dry), then look for Karl R. Popper, The Logic of Scientific Discovery, New York: Harper & Row, 1968
- Pfranz
