The importance of falsifiability

OK, a painful question to ask, perhaps because the answer will probably be handed to me awfully quickly, but nonetheless, what is the importance of falsifiability?

Its a term that’s turned up from time to time, but I’m unsure of its importance or relevance. From the Wikipedia article.

What is the significance of the falsifiable statement? As far as I can see I would accept the second statement simply from knowing that little green men are unlikely to exist. What does making it falsifiable add?

I strongly suggest that you read Popper’s essay on falsifiaction to get a good handle on this. It’s not very long and explains it far more clearly than I can.

the point of falsifiability is that it gives us an objective standard by which to measure the truth value of a concept. We don’t need to rely on your subjective assessment that Martians are unlikely, which is just as well because many people will tell you that it is unlikely that little green men haven’t visisted Earth. Whether these things are likely or unlikely depend entirely on your starting assumptions.

To paraphrase Popper, the point of falsification is that it prevents us from misleading ourselves, albeit unintentionally or subconsciously. It might be the case that you reject the idea of visitors from Mars because you think that visitors from Mars are unlikely, but what happens if you believe something to be likely that is actually untrue? As Popper notes, followers of all sorts fo nutty ideas like astrology or spirit mediums believe that it is likely that what they accept is true. After all there is no reason why it is unlikley that the stars control our destiny or that the dead can speak. Moreover the followers can point to countless examples of where these things are suported by evidence.

What falsifiability does is enable us to reject objectively test these ideas by asking them to make predictions. If the prediction fails then the idea can be rejected regardless of how likely you may personally think it to be. And if it succeeds then the idea can be held to be true regardless fo whether you think it is unlikely. Thatsl why we can say, for example, that there are no major genetic differences between Caucasians and Negroes despite the fact that a few decades ago such an idea was held to be highly unlikely.

Interesting, I’ll check the link, thanks.

The problem with the simplistic view of falsifiability is that the real world often doesn’t bother to make things that clear. As the minimal requirement for a theory, it is very reasonable. In some cases a hypothesis gets falsified so clearly there is no question about it. But in most cases experimental results or results of observations can be interpreted in several different ways.

Those resisting the falsification of their pet hypothesis can range all the way from people making very reasonable alternate interpretations of a result to people who keep adding special cases to the hypothesis to make it fit the data. For instance, creationism, as it was posited three centuries ago, is a falsifiable hypothesis, and it got falsified. Present day creationists seem to be of the special cases variety. You can’t blame the hypothesis, only its proponents.

Making a falsifiable hypothesis isn’t that hard. Really trying to falsify it is much harder, especially if it’s a really cool one.

In a nutshell, it’s a way of saying “there are a number of ways this could have been proven wrong, but since we checked them all and it still stands, it’s most probably right”, as opposed to “this may be right or wrong, but there’s no way to tell”.

You may also be very interested in this recent book, The Black Swan, which explains this in an approachable and thought-provoking manner.

A specific example, here: Crackpots will often point out that the “scientific establishment” (whatever that means) attacked the ideas of Galileo, and of Einstein, the implication (by those crackpots, at least) being that the “establishment” isn’t to be trusted. Quite the contrary is the case, however: Einstein’s theories were right, and the scientific establishment of the day was right to attack them. Of course, the theories of relativity withstood all of those attacks, and it’s precisely because they withstood so many attacks that we trust relativity.

Moved to Great Debates for lack of falsifiablity. :smiley:

Gfactor, General Questions Moderator

As a poster I’ll add that this audiobook covers the field very nicely:

In Galileo’s day, there was no scientific establishment to attack anything. As for Einstein, do you have some cites as to how he was attacked? I’m not saying that there weren’t any (there always are for anything significant) but the effort devoted to checking relativity through astronomical observation shows that they were considered significant. I wouldn’d consider the withholding of judgement until after the observations an attack, but rather waiting for confirmation, which is very appropriate.

I second the recommendation to read Popper’s essay; the importance attributed to falsifiability is basically due to him, and it’s enlightening to see where he was coming from with the idea; to get a grip on what exactly he was, and wasn’t, proposing, and the reasons for his proposal. You needn’t necessarily agree with Popper, of course, or you may only agree in part, but nonetheless, it’s worthwhile to understand exactly what his arguments were.

(In particular, it’s useful to understand the distinction between the notions of “meaningful” and “scientific”, Popper arguing against their conflation and only proposing falsifiability as a method of demarcation for the latter; it’s also enlightening to see Popper’s discussion of the problem raised by Voyager above, that any theory can be continually “salvaged” from falsification with enough contrivance by ardent believers)

see (about 1/3 down the page)

100 against Einstien" was a (Largely) Antisemetic based diatribe against Einstien’s Theory of Relativity. Reading it, one finds people speaking of “the Either” as if it were a proven fact. (As Example).

Einstien’s response (paraphrased)… “100? - Bah… it only takes one to be right…”


“If I were wrong, then one would have been enough!” IIRC.

I say Ether, you say Either…

“The earth has been visited by little green men” is absurd on its face. Also, there aren’t legions of people who are vested emotionally in believing that the earth has been visited by little green men.

Falsifiability comes in handy for questionable claims that are not absurd and have a lot of people who want to believe in them. It may be difficult to show that these claims are wrong, but the next best thing is to show that they are unfalsifiable and therefore not scientific.

For example, suppose you are arguing with somebody who claims that “God exists.” It’s difficult to prove that God doesn’t exist. However, you can ask them “What evidence would it take to show you that God does not exist?” If there is no such evidence, then you have shown that the claim is unfalsifiable and therefore not scientific.

The concept of falsifiability is also useful to keep people from hiding behind vague and ambiguous hypotheses. If you ask the person to describe an experiment that could test or falsify his hypothesis, it will force the person to define his claim clearly enough so that it can be tested.

In another thread, somebody made the following statement:

It’s difficult to even understand this claim well enough to disprove it. However, a reasonable response might be the following:

Here was my favorite answer:

And here was my ultimate response:

See? By demanding that a person describe what evidence would refute his claim, you can show that the claim is non-scientific.

Of course, it’s also valuable to test ones own beliefs in this way. Anything you believe, you should ask yourself “what evidence would change my mind?” If no such evidence exists, then you are probably fooling yourself.

Assuming by little green men you mean some sort of alien, there is nothing absurd about this statement - but it isn’t a very useful one, since it is too general. The Earth is very old, and we might well have been visited 100 million years ago. But, since there is no evidence expected, it is an unfalsifiable and thus useless statement. (Though it might be a true one.)

“The earth has been visited by little green men” is a poorly stated hypothesis - except perhaps as a premise for a science fiction story or a religion.

If the statement had been “the earth has been visited by intelligent extraterrestrials in the past,” then yeah, it’s not absurd on its face.

That’s what I thought you meant. If the statement was supposed to mean “being visited by little green men now” then I’m with you all the way.

So? It was just a value-free example, I’m sure. Replace it with “the earth is hollow”, “the moon landings were faked”, “mars is covered by artificial canals”, or “AIDS causes HIV” if you like. There are or were legions of people vested emotionally in those, despite them being absurd on their faces. It’s merely a vehicle to illustrate the principle being discussed.

Sure. The question being posed was, essentially “why do we need to concept of falsifiability when it’s obviously unlikely that the earth was visited by little green men”?