created by maxitobonito on 02/01/2017 at 19:42 UTC
3 upvotes, 3 top-level comments (showing 3)
Comment by restricteddata at 02/01/2017 at 20:15 UTC*
10 upvotes, 0 direct replies
Falsifiability is a property of a statement about the world. It was proposed by Karl Popper as a way to tell scientific statements from metaphysical statements. If a statement is falsifiable, it is part of science. If it is not, it is not. That doesn't mean it's wrong or stupid, it just means it's not science.
So specifically what it means is, if there is no way to tell if a statement is *false*, then it's not part of science. That doesn't mean you have to be able to prove it false, of course — many true things are falsifiable. But it means there must be a way to "test" it, and specifically to test it by proving it *wrong*.
Let's go with a concrete example. Here is a statement about the world: "There is an invisible, undetectable unicorn that keeps the Sun shining." If this were true, I would note, the Sun would shine. I look into the sky and lo and behold, the Sun is shining! And lo, I can come up with an experiment: if I shout out, "unicorn O unicorn, make the Sun shine tomorrow!", you will see the Sun shine tomorrow.
Ah, but what if you *don't* shout that out? Well the unicorn loves us and the Sun so he'll keep shining anyway, but I think he's probably sad to not hear his name.
Great, says Popper. That's a statement for why the Sun shines, to be sure. But your only evidence is about proving it *true*. It's not science unless there is something you can do to prove it *false*. In this situation there is no way to disprove the statement — if I call to the unicorn, the Sun shines, if I don't, the Sun shines. This statement cannot really be tested, and the fact that all visible evidence seems to align with the theory does not mean a damned thing, because you can come up with an infinite number of theories that fit the evidence *if* they are not falsifiable.
And so this is why this matters. You can always come up with theories that fit any evidence with exceptions. What matters to Popper are places where you've really put it to the test. So if instead I say, well, my unicorn *requires* me to sing to it every day... I can test that by not singing to it. "The Sun only rises because a unicorn gets sun to every day, and wouldn't rise if nobody sang to it" is a totally falsifiable, and thus scientific, statement. It happens to be testably *wrong*. But that's not what Popper cares about.
Let's take a less silly example: "large amounts of mass can bend the direction that light travels." This was a consequence of what Einstein argued with his General Relativity theory. Pretty cool statement. Is it falsifiable? Yes — you can do experiments (the first involved photographing stars near the Sun during a total solar eclipse) to see if it's true. If the stars are where Einstein predicted they'd be — then the statement is judged a true one. If they aren't, then Einstein is wrong. Either way, it's still falsifiable, so it's science.
Popper developed this approach because at the time a lot of people thought the key distinguishing factor between science and non-science was that they made statements about evidence ("verificationism"). Popper saw a lot of things that made statements about evidence that didn't look to him like science. Freudianism was high on his list: Popper thought they were essentially non-falsifiable. Freudians said their model of the mind was correct because their patients got better. If patients didn't get better, it was the patients' fault, or maybe the analyst, but never the model of the mind. The model could never be tested in a way that the Freudians thought would prove it wrong — so to Popper, whatever its value, it wasn't science.
It is worth noting that this isn't a perfect way to distinguish science from non-science, and the usefulness of falsifiability is considered somewhat limited. There are lots of sub-issues that come up if you pry into it, like, what if it's only *hypothetically* falsifiable (e.g. it requires all of the energy in the universe to test), or what if it's just not *yet* falsifiable, and so on. The fact that String Theory is not falsifiable (as of yet, anyway) has led a lot of scientists to declare that falsifiability is only partially useful — you can make of that what you will.
Comment by Kriscolvin55 at 02/01/2017 at 19:51 UTC
5 upvotes, 2 direct replies
You have to be able to prove something is false to be able to prove it's true.
Example A: I say that I can run faster than you. We race. I either beat you, or you beat me in the race. That is falsifiable because you could prove that I cannot run faster than you.
Example B: I say that God is real. There is no way for me to prove that is correct. But, there is no way to prove that I'm incorrect. All we can do is debate, but nobody can prove anything.
Comment by 500_Shames at 02/01/2017 at 21:13 UTC
3 upvotes, 0 direct replies
Example: I claim that there is always a hitler standing behind you that disappears when observed.
Can you disprove this claim? Well, no, I covered my ass by saying that I'm right and that any time you check, it will disappear. Does this mean that my "Schrodinger's Hitler" hypothesis should be taken as fact? No, because there's no condition under which it is false and therefore is not falsifiable.
Let's try again:
I claim that there is a hitler in your bathroom right now.
Can you disprove this claim? Yes, you could check your bathroom for Nazi leaders. If you check your bathroom and find a Führer, then we have evaluated the falsifiable parameter and have therefore established that this claim is true. If there is no hitler, then we reject your hypothesis.
Falsifiability is so important because it allows us to clearly distinguish between what reality looks like when a claim is true and when a claim is false. If you cannot tell any difference, then your claim is ultimately pointless. Say that there really is a hitler behind you at all times that no one can observe. Why does it matter if it doesn't influence the world? How is it any different from the world without a hitler behind you?