Argument from Ignorance · 5:18am Dec 15th, 2012
To keep up the tradition, I'm going to keep posting one of these a day.
Argument from Ignorance
There (is no evidence/is not enough evidence/are too many holes in the evidence) for A, therefore A is false.
Also:
There (is no evidence/is not enough evidence/are too many holes in the evidence) against A, therefore A is true.
Example A (a very popular one!):
Lojika McPhallussy: There is no evidence proving the existence of God, therefore God can't exist.
Example B (another very popular one!):
Lojika McPhallussy: There is no evidence disproving the existence of God, therefore God must exist.
Once again, this isn't always a fallacy—often it depends on who, exactly, holds the burden of proof. For example, when disproving a scientific theory, the burden of proof is usually upon the ones proposing the newer theory, partly because it is assumed that the older one has already been explained and established. For legal systems around the world, this can vary. In America, for instance, the burden of proof is upon the prosecutor because people are presumed to be innocent until proven guilty. In China, this is the other way around, with the burden of proof being on the defendant. In other words, if the burden of proof is upon you, an argument from ignorance (from you) will be fallacious. If the burden of proof is upon your opponent, an argument from ignorance can be acceptable. Deciding exactly who the burden of proof lies upon, however, is another matter entirely.
Related to, but different from:
I personally cannot believe or understand evidence for A, therefore A is false.
Also:
I personally cannot believe or understand evidence against A, therefore A is true.
Example A:
Ida Praposar: A study has shown that smoking and lung cancer are related. Apparently cigarette smoke contains carcinogens like Acrolein and radioactive lead.
Lojika McPhallussy: Radioactive lead? That's silly. Lead can't be radioactive. Lead protects you from radiation. That study must be bunk.
Example B:
Ida Praposar: It turns out that Amanda isn't really a man. She and several trainers at the gym have confirmed that her flat chest and manly biceps are the result of five years of hardcore weightlifting.
Lojika McPhallussy: Female weightlifters? Preposterous! I've never heard of such a thing. Amanda is obviously lying about this. Also, she's Amanda.
Example C:
Ida Praposar: .999... is equal to 1. I have a couple of proofs. For instance 1/3 is equal to .333..., 2/3 is equal to .666..., and presumably, if you add another 1/3 you would get .999..., but 3/3 is equal to 1.
Lojika McPhallussy: My calculator says that 1/3 is .333333333, but 2/3 is .666666667. If you add another 1/3 you would get 1. .999... is not equal to 1.
Ida Praposar: Your calculator is rounding an infinite series of digits into an eight-digit number. Even if your idea were true, there is still an algebraic equation that would prove .999... is equal to 1. If you let x = .999... 10x would be 9.999... and if you take away 1x, you would have 9x and a value of 9. If you divide the entire equation by 9, you would get the statement x=1.
Lojika McPhallussy: You're being stupid. Calculators are never wrong, and I don't really understand what you're doing there with the "x"s, but it looks like you're just manipulating the equation to get the answer you want. Besides, how can one number be another number? I don't believe a word of this nonsense.
I like to call this one "argument from stupidity". It has an official name (argument from personal incredulity or something like that), but I like mine better. Unlike the earlier examples, this kind of argument is almost always fallacious. The key difference between an argument from ignorance and an argument from stupidity is evidence. A lack of evidence is what makes an argument from ignorance, while in an argument from stupidity, even if there is plenty of good evidence towards a claim, the person hearing the evidence will refuse to believe it because they do not understand, or do not want to understand. This is not to say that questioning other people's statements is fallacious—if someone merely asks another person to clarify what they see as a confusing argument, it is not automatically an argument from stupidity. arguments from stupidity only happen when someone tries to use their lack of understanding to discredit another person's claim. Particularly bad offenders will often follow up their argument from stupidity with an ad hominem. It's usually good to either ignore these people or to find out where they live so you can shoot them in the face.
But if you do decide to shoot them in the face, try to make sure that the prosecutor only has arguments of stupidity, ignorance, or circumstance. And wear gloves. And don't use a gun registered in your name..
Good read. Nice to have a name for it, people do this to me all the time.
You couldn't help yourself, could you?
Remind me to ask you exactly what a "burden of proof" is later, would ya
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ofc not
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Some wikipedia:
[1]
[2]
I'm surprised that you didn't mention the null hypothesis, what with how often it gets confused with an argument from ignorance.
For instance, "There is no evidence proving the existence of God, therefore God can't exist" is the null hypothesis for the issue of whether or not God exists, though it would be clearer if the "can't" is replaced by "doesn't". This is due to the burden of proof you were talking about - the burden of proof is on those who propose an explanation, so a lack of proof on their part means that the null hypothesis should be assumed.
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That's quite an assertion, mind proving it real quick for my benefit? Because that's exactly the kind of talk that I can't wrap my wee little brain around. And I can't find it explained anywhere either—just look at that second link Sessalisk posted. The Wikipedia article for "Philosophic Burden of Proof" is like 100 words long! How am I supposed to learn anything from that?
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What assertion are you referring to? If you are asking how to determine who holds the burden of proof, then, to quote wikipedia:
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Upon reflection, I think I'm actually wondering about these two separate but related statements:
1. "The burden of proof is on those who propose an explanation"
2. "a lack of proof on their part means that the null hypothesis should be assumed"
Regarding the first, I'm not sure in what sense the "burden" is being claimed to exist. Is it claimed to be an objective epistemological standard which all knowledge must meet? Is it merely a social convention governing discourse between different people? I don't understand what it's supposed to be. I often see people claiming that there is a burden of proof and that it needs to be met, but why? What is the scope of this burden? What is its purpose? It seems ambiguous, to me, to just claim without qualification or explanation that there is a "burden of proof".
As for the second: why should the null hypothesis be assumed in that case? This seems like a sizable claim, and in the interest of seeing whether the claim is self-consistent, I'd like to see a proof of it. Failing that, I'd at least like to know in what sense you are using the word "should". Is this a moral claim? Epistemological? Pragmatic? It seems unclear to me, anyway.
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Ah, alright. I'll address your points in order:
1. "Burden" isn't being used in the sense of a quantified "amount" of proof, but instead as an expression of which side of an argument needs to provide support. For instance, in the USA, the burden of proof in on the prosecution to provide proof that the defendant is guilty, not the other way around. I'm not sure what you mean by "scope", though - the burden of proof can shift many times in a discussion, if that helps. To more directly answer your question, it's a sort of formalization of the difference between someone who is claiming something and someone who is arguing against said claim.
2. The best way I've heard this explained is that the null hypothesis is a sort of "default position" - using the analogy of the US court systems, the null hypothesis is that the defendant is innocent. More generally, you assume the null hypothesis whenever you don't have enough proof to make another conclusion.
> Once again, this isn't always a fallacy—often it depends on who, exactly, holds the burden of proof.
> For example, when disproving a scientific theory, the burden of proof is usually upon the ones proposing the newer theory
Not quite: It is not correct to declare a hypothesis FALSE on the basis of a lack of evidence. Rather, a good scientist must declare that "there is not enough evidence to justify this hypothesis", and might complain that the hypothesis is worthless because it is unfalsifiable. (That is to say, there is no piece of evidence which may be presented that would make the speaker acknowledge that their hypothesis is wrong. If a hypothesis cannot be falsified, it is not a hypothesis at all -- it is a mere belief based on faith.) We can say that we assume the hypothesis is false because of this, but that's with an implied "for now" and "until you come up with something more convincing".
We can't state categorically that aliens didn't built the pyramids, but we have this gigantic pile of data that says aliens were not necessary, and your pile of evidence consists of suggestion, innuendo, and what our theory says is misinterpretation. Therefore we reject your theory and assume it is false, pending a more solid pile of evidence.
* Well, we can for the purpose of normal english conversations, but in a scientific sense we aren't saying "that is false due to lack of evidence".
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The null hypothesis is always that nothing unusual has occurred. In a criminal case, the null hypothesis is that no crime has been committed (You say one has been? Then show me the evidence of a crime.) Normally the police handle this part; they generally don't make arrests if there's no evidence that there was a crime (and in this case, a witness's or victim's statement is evidence). Once you actually get to court, the null hypothesis is that this particular person was not involved in the crime as described. (You say they were? Then provide evidence.) This is the basis of "innocent until proved guilty".
It's a mistake to leap straight to trying to explain a reported "strange phenomenon" without first falsifying the null hypothesis (that is, proving that something of interest occurred). If somebody reports that a UFO was sighted over Las Vegas and had a radar trace, you don't start by trying to figure out how a mysterious radar trace appeared -- the first thing you have to do is show that something was sighted and there was in fact a mysterious radar trace. (You'd be shocked how often UFO tv shows talk about how the military picked up a radar blip and sent up fighters when the records show that no such thing actually happened.)
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http://en.wikipedia.org/wiki/Scientific_theory
versus
http://en.wikipedia.org/wiki/Hypothesis#Scientific_hypothesis
pls read
I'm using 'theory' in the english language sense of a general statement of how things work, not the scientific sense of a well-supported and coherent explanation.
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...Except you used your colloquial definition in an attempt to refute an example specifically pertaining to scientific theories.
...
Fine, I edited my post to correct the language.
I wasn't actually trying to refute anything you said, I was just drawing a distinction between declaring something false and stating that it lacks sufficient evidence.
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"> Once again, this isn't always a fallacy—often it depends on who, exactly, holds the burden of proof.
> For example, when disproving a scientific theory, the burden of proof is usually upon the ones proposing the newer theory
Not quite: It is not correct to declare a hypothesis FALSE on the basis of a lack of evidence. Rather, a good scientist must declare that 'there is not enough evidence to justify this hypothesis', and might complain that the hypothesis is worthless because it is unfalsifiable."