Fallacies from Chapter 4
Appeal to Ignorance
no evidence is given, so we can believe otherwise
Since we can't prove something is true then we are entitled to believe it is false; or vice-versa
A not proven true. Thus, A is false
can assume, can believe, can't prove it, there's no evidence, must be so
How to Explain
state that the absence of evidence does not prove the opposite; the burden of proof is on the person making the claim and not the listener
God must exist since it's never been proven that He doesn't.
1. The fallacy of appeal to ignorance involves taking the absence of evidence for conclusive proof that a claim is either true or false. As some may falsely assume by its name, this fallacy is NOT necessarily related to pure stupidity.
2. If there is insufficient proof or evidence for a claim, we should neither believe it nor disbelieve it. When good reasons are lacking then the rational conclusion to draw is that we just don't know. Many of these arguments result from a failure to consider a wide enough range of ways in which evidence may arise.
3. It is important to note that a lot depends on whether there has been a reasonable search for evidence. The problem here is that a 'reasonable search' may be very subjective at times.
4. The failure to find evidence when a reasonable search has been held does count as evidence against a claim, when the search would very likely find something if it was there. For example: if several medical tests to see if there was blood in someone's urine fails to find blood, then we should be satisfied that a reasonable search has been conducted. Thus, it is very unlikely that the person has blood in their urine.
On the other hand, suppose someone loses their keys and proceeds to turn their house upside down looking for them. After not finding the keys, they proclaim that the keys are not in the house. Was there a reasonable search? How can we measure what a reasonable search was in this case? Suppose they find the keys later in a place in the house that they didn't search. The difficulty is in determining what is a reasonable search.
Note that Sherlock Holmes once said, "If you eliminate the impossible then whatever remains, however improbable, must be the case. A good question is 'how do we know when we've eliminated the impossible?".
5. A common type of argument is one where the appeal to ignorance is implied. For example: 'There's no evidence to show that President Bush isn't doing all he can in the war against terrorism.' This implies that he is in fact doing all that he can in the war against terrorism.
6. If someone were to offer you an argument with little or no evidence and then say 'prove me wrong', they are committing the appeal to ignorance fallacy. Essentially they are saying that 'since you can't prove me wrong, then I must be right.' But you should counter that the burden of proof rests on them, not you, since they are the one offering the argument.
7. Appeal to Ignorance on the Internet
1. God must exist since it's never been proven that He doesn't.
Analysis: That it's never been proven that God doesn't exist does not prove that God does exist. One can change the argument to the following to see why it fails, that is, 'God must not exist since it's never been proven that He does exist. Regardless, it should be clear that a reasonable search has not been held.
2. Since no one has been able to prove Iraq doesn’t have weapons of mass destruction, we can conclude that Iraq must have them.
Analysis: A reasonable search had not been held when this was argued and time has shown after much searching that Iraq did not possess WMD.
3.Senator McCarthy: "I do not have much information on this except the general statement of the agency that there is nothing in the files to disprove your communist connection".
Analysis: The implication is that the person is guilty of a communist connection because there is no proof that he is not a communist. A clear case of appeal to ignorance. It is also unclear as to what would count as proof that someone is not a communist.
4. The fact that no traces of Hitler's remains we're ever found has led some people to conclude that he must still be alive.
Analysis: An absurd conclusion that Hitler must still be alive.
5. If Darwin's theory can't adequately explain the origin of our species then it must have been the work of an intelligent designer.
Analysis: A lack of explanation is not good enough for science. Who or what is this designer? How does it operate? When should we expect to see the designer operating in today's world? None of these questions are answerable, because the designer falls outside of natural processes. This answer simply does not fit the definition of a scientific explanation.
6. From a John Wayne movie:
John: The murderer must be hiding in the swamp.
Deputy: Why's that?
John: Well, nobody's seen him anyplace else.
Analysis Again, there was no reasonable search. To know this, you'd have to see the movie.
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Last updated: 15:32 on 30 January 2013
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