I gotta thank you. I guess I pretty much took the notion of falsifiability to be Popperian. I had thought his was a response to the positivists (who that that something had to be provable to be scientific). But the problem was that the positivists didn't answer Hume's question about induction. I've never actually read anything Bacon wrote, and I'm sure that I'm a worse person for it.
The problem with alchemy - and a lot of other things that pretend to be science - is that there is no way of proving they are false - EVEN IF THEY ARE FALSE. Saying that a thing is falsifiable is not the same thing as saying that it is false. What falsifiable means - at least what the proponents of the notion intend it to mean - is that a thing is capable of being proven false - if it is in fact false.
It's a curious use of language, I admit, but scientists start from the premise that they don't know the answer (at least in the Popperian / Baconian view). They have this explanation, this hypothesis, about how things work, but they aren't sure about it. For it to be a scientific hypothesis, it must be falsifiable, that is "IF IT IS FALSE, there must be a way to prove that it is false."
For example, "God exists" is not a scientific hypothesis. It can't be proven false, even if it is false. Of course, this doesn't mean that god doesn't exist. Saying that something is not scientific does not mean that it's false or that it's useless or that it's wrong.
OTOH, evolution is falsifiable, because IF IT IS FALSE, then it can be proven false. (That doesn't say that it is is false.) How to prove evolution false? Well, find me a fossil hominid that has a clean date back to 2 billion years. I think that would pretty much be a nail in the coffin.
A lot of the terminology and conclusions of logic are very confusing. One thing that still nags at me is the phrase "ONLY IF." Really makes no sense linguistically and you have to memorize the meaning (actually, most people who use the phrase don't even think about it). Another weirdness is the value of the conditional p>q. If the premise is false, the value of the conditional is true regardless of the value of the conclusion. So F->F evaluates to T.
I'm not sure of a relation offhand, but this factiod, might even shed some light on 'falsifiability'.
k
