What are Logical Fallacies?

[sean.a...@gmail.com]

Description of Fallacies

In order to understand what a fallacy is, one must understand what an argument is. Very briefly, an argument consists of one or more premises and one conclusion.

A premise is a statement (a sentence that is either true or false) that is offered in support of the claim being made, which is the conclusion (which is also a sentence that is either true or false).

There are two main types of arguments: deductive and inductive.

A deductive argument is an argument such that the premises provide (or appear to provide) complete support for the conclusion. An inductive argument is an argument such that the premises provide (or appear to provide) some degree of support (but less than complete support) for the conclusion.

If the premises actually provide the required degree of support for the conclusion, then the argument is a good one.

A good deductive argument is known as a valid argument and is such that if all its premises are true, then its conclusion must be true. If all the argument is valid and actually has all true premises, then it is known as a sound argument.

If it is invalid or has one or more false premises, it will be unsound.

A good inductive argument is known as a strong (or "cogent") inductive argument. It is such that if the premises are true, the conclusion is likely to be true.

A fallacy is, very generally, an error in reasoning. This differs from a factual error, which is simply being wrong about the facts. To be more specific, a fallacy is an "argument" in which the premises given for the conclusion do not provide the needed degree of support.

A deductive fallacy is a deductive argument that is invalid (it is such that it could have all true premises and still have a false conclusion).

An inductive fallacy is less formal than a deductive fallacy. They are simply "arguments" which appear to be inductive arguments, but the premises do not provided enough support for the conclusion.

In such cases, even if the premises were true, the conclusion would not be more likely to be true.

http://www.nizkor.org/features/fallacies/


A fallacy is incorrect argumentation in logic and rhetoric resulting in a lack of validity, or more generally, a lack of soundness. Fallacies are either formal fallacies or informal fallacies.

http://en.wikipedia.org/wiki/List_of_fallacies

So Fallacy is an unsoundness in the *reasoning* of an argument. It isn't about the facts of a matter, or true premises, but about how those are used in argument suggesting a particular conclusion .. that one might be claiming must also be true or more likely to be true.

Because fallacies are an error in logic you do not need to know anything about the *content* or the truth or not of the facts of a matter.

This means you see that one can still have most of their facts correct and yet still draw poor unsound arguments based on those .. that amounts to an error in reasoning alone.

A way to look at the issue overall is to notice that when it comes to understanding something about history ore the like, the two aspects to it .... first the accuracy of the known records, and the reasoning that one applies to those premises. Two very separate issues. In heated arguments these two aspects often get confused and muddled up.

There's a big difference between discussions about what are the actual facts or premises, and discussions that might prove an unreliable argument (a logical fallacy) or perhaps support a good one.

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http://en.wikipedia.org/wiki/Argument_from_fallacy

Argument from fallacy is the formal fallacy of analyzing an argument and inferring that, since it contains a fallacy, its conclusion must be false.[1]

It is also called argument to logic (argumentum ad logicam), fallacy fallacy,[2] or fallacist's fallacy.[3]

Fallacious arguments can arrive at true conclusions, so this is an informal fallacy of relevance.

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http://www.nizkor.org/features/fallacies/appeal-to-authority.html

Also Known as: Fallacious Appeal to Authority, Misuse of Authority, Irrelevant Authority, Questionable Authority, Inappropriate Authority, Ad Verecundiam

Description of Appeal to Authority

An Appeal to Authority is a fallacy with the following form:

Person A is (claimed to be) an authority on subject S.
Person A makes claim C about subject S.
Therefore, C is true.

This fallacy is committed when the person in question is not a legitimate authority on the subject. More formally, if person A is not qualified to make reliable claims in subject S, then the argument will be fallacious.

This sort of reasoning is fallacious when the person in question is not an expert. In such cases the reasoning is flawed because the fact that an unqualified person makes a claim does not provide any justification for the claim. The claim could be true, but the fact that an unqualified person made the claim does not provide any rational reason to accept the claim as true.

When a person falls prey to this fallacy, they are accepting a claim as true without there being adequate evidence to do so. More specifically, the person is accepting the claim because they erroneously believe that the person making the claim is a legitimate expert and hence that the claim is reasonable to accept.

Since people have a tendency to believe authorities (and there are, in fact, good reasons to accept some claims made by authorities) this fallacy is a fairly common one.

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Includes: Appeal to Ignorance ("Ad Ignorantiam")

Description of Burden of Proof

Burden of Proof is a fallacy in which the burden of proof is placed on the wrong side. Another version occurs when a lack of evidence for side A is taken to be evidence for side B in cases in which the burden of proof actually rests on side B. A common name for this is an Appeal to Ignorance. This sort of reasoning typically has the following form:

Claim X is presented by side A and the burden of proof actually rests on side B.
Side B claims that X is false because there is no proof for X.
In many situations, one side has the burden of proof resting on it. This side is obligated to provide evidence for its position.

The claim of the other side, the one that does not bear the burden of proof, is assumed to be true unless proven otherwise. The difficulty in such cases is determining which side, if any, the burden of proof rests on.

In many cases, settling this issue can be a matter of significant debate. In some cases the burden of proof is set by the situation. For example, in American law a person is assumed to be innocent until proven guilty (hence the burden of proof is on the prosecution). As another example, in debate the burden of proof is placed on the affirmative team. As a final example, in most cases the burden of proof rests on those who claim something exists (such as Bigfoot, psychic powers, universals, and sense data).

http://www.nizkor.org/features/fallacies/burden-of-proof.html

Argument from ignorance, also known as argumentum ad ignorantiam or "appeal to ignorance" (where "ignorance" stands for: "lack of evidence to the contrary"), is a fallacy in informal logic.

It asserts that a proposition is true because it has not yet been proven false, it is "generally accepted" (or vice versa).

This represents a type of false dichotomy in that it excludes a third option, which is that there is INSUFFICIENT INVESTIGATION and therefore INSUFFICIENT INFORMATION Disclosure to prove the proposition satisfactorily to be either true or false.

Nor does it allow the admission that the choices may in fact not be two (true or false), but may be as many as four, (1) true, (2) false, (3) unknown between true or false, and (4) being unknowable (among the first three).[1]

In debates, appeals to ignorance are sometimes used to shift the burden of proof.

http://en.wikipedia.org/wiki/Argument_from_ignorance

Mixed into all the above possibilities in reasoning out things, are one's personal beliefs and biases. Much is said about these matters in the Eckankar teachings imho.

[sean.a...@gmail.com]

Absence of evidence

Absence of evidence is the absence, or lack of, any kind of evidence that may show, indicate, suggest, or be used to infer or deduce a fact.

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Argument from ignorance,
also known as argumentum ad ignorantiam or "appeal to ignorance"

where "ignorance" stands for: "lack of evidence to the contrary"),
is a fallacy in informal logic.

Basic argument
Arguments that appeal to ignorance rely merely on the fact that the veracity of the proposition is not disproven to arrive at a definite conclusion.

These arguments fail to appreciate that the limits of one's understanding or certainty do not change what is true.

They do not inform upon reality. That is, whatever the reality is, it does not “wait” upon human logic or analysis to be formulated.

Reality exists at all times, and it exists independently of what is in the mind of anyone.

And the true thrust of science and rational analysis is to separate preconceived notion(s) of what reality is, and to be open at all times to the observation of nature as it behaves, so as truly to discover reality.

This fallacy can be very convincing and is considered by some[2] to be a special case of a false dilemma or false dichotomy in that they both fail to consider alternatives.

A false dilemma may take the form:
If a proposition has not been disproven, then it cannot be considered false and must therefore be considered true.

If a proposition has not been proven, then it cannot be considered true and must therefore be considered false.

Such arguments attempt to exploit the facts that
(a) true things can never be disproven and
(b) false things can never be proven.

In other words, appeals to ignorance claim that the converse of these facts are also true!

THEREIN LAYS THE FALLACY

To reiterate, these arguments ignore the fact, and difficulty, that some true things may never be proven, and some false things may never be disproved with ABSOLUTE CERTAINTY.

The phrase "absence of evidence is not evidence of absence" can be used as a shorthand rebuttal to the second form of the ignorance fallacy (i.e. P has never been absolutely proven and is therefore certainly false).

Most often it is directed at any conclusion derived from null results in an experiment or from the non-detection of something.

In other words, where one researcher may say their experiment suggests evidence of absence, another researcher might argue that the experiment failed to detect a phenomenon for other reasons.

Matters of confusion

Carl Sagan explains in his book The Demon-Haunted World:

Appeal to ignorance: the claim that whatever has not been proved false must be true, and vice versa. This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence.[3]

For instance, absence of evidence that it rained (i.e. water is the evidence) may be considered as positive evidence that it did not rain. Again, in science, such inferences are always made to some limited (sometimes extremely high) degree of probability and in this case absence of evidence is evidence of absence when the positive evidence should have been there but is not.

Arguments from ignorance can easily find their way into debates over the existence of God. It is a fallacy to draw conclusions based precisely on ignorance, since this does not satisfactorily address issues of philosophic burden of proof.

But null results are not ignorance and can be used as evidence to achieve a given burden of proof.

http://en.wikipedia.org/wiki/Argument_from_ignorance

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Description of Poisoning the Well

This sort of "reasoning" involves trying to discredit what a person might later claim by presenting unfavorable information (be it true or false) about the person. This "argument" has the following form:

Unfavorable information (be it true or false) about person A is presented.
Therefore any claims person A makes will be false.

This sort of "reasoning" is obviously fallacious.

The person making such an attack is hoping that the unfavorable information will bias listeners against the person in question and hence that they will reject any claims he might make.

However, merely presenting unfavorable information about a person (even if it is true) hardly counts as evidence against the claims he/she might make.

http://www.nizkor.org/features/fallacies/poisoning-the-well.html


This poisoning of the well is also very common, it's human nature I suppose.