This post tries to sketch a rule of the thumb to quickly check whether an idea/theory/belief is utterly useless or not. I have admittedly adapted it from the [[Bertrand Russell|russellian]] definition of [[Science]]. Recall that utterly useless ideas are not necessarily wrong. They are just that: utterly useless.
There is a single basic question you have to ask yourself when you invent/encounter a flashy new theory or idea like [[Psychokinesis|telekinesis]] or [[homeopathy]]:
Can I imagine any conceivable way of refuting this theory?
If the answer is “no”, then the theory is bullshit.
If you accept this, you are bound to abandon the theory if someone comes up with a valid experiment at which your theory fails (if someone challenges your telekinetic powers and you can not shut her mouth, you must accept you don’t have telekinetic powers).
On the other hand, if you don’t accept the above premise, you must, without excuse, believe in any other theory that can not be proved wrong, such as the [[Invisible Pink Unicorn]] or the [[Flying Spaghetti Monster]]. Failing to do so will undoubtedly qualify you as an absolute hypocrite.
Now, the long explanation…
Proving something true is theoretically impossible, but proving something wrong is trivial: if I say that all swans are white, no matter how many white swans I see, I will never be sure that the theory is true. On the other hand, after the first black swan I see, I will conclude without doubt that the theory was wrong.
Thus, “proving” some theory is usually equaled to designing an experiment in controlled conditions, where a result is expected from the theory, and we get precisely that result in the experiment. Obviously, we could have obtained a different result, and our theory would have been proved wrong. It is precisely the fact that a different result could potentialy refute our theory what makes the desired result confirm it. It follows that, if there is no conceivable circumstance under which the experiment could have failed, our theory can not be disproved, and therefore can not be “proved” through absence of refutation.
Take for example a [[precognition|seer]] who claims to be able to see the future. Her theory is not necessarily bullshit: one can devise a test, failing which would mean that she is wrong. For example, one can ask her to “see” something that she can not access by normal means, and that she can not guess by chance, for example the next lottery winning number. If she guesses correctly, the theory is temporarily accepted. If she fails, the theory is dropped.
Not it comes the funny twist: any argument that tries to make the precognition theory above survive after a failure (e.g. “I do not control when I can see the future”, “I only see abstract visions that I have to interpret afterwards”, and so on… you know the thing), automatically turns it into bullshit. Directly. And that because of the little rule of the thumb I present above.
