Chickenhawk Fallacy

A Chickenhawk is a person who takes a hawkish or aggressive stance on military issues but has never been to war or served in the military. It can also be applied to the one using the Chickenhawk Fallacy which is to deny standing to discuss military issues to anyone who is not themselves at war or a veteran.

There are many reasons why the Chickenhawk Fallacy is invalid logic, but basically it's just an ad hominem, attacking the arguer rather than the argument.

Latin: ad hominem buteo gallus

Non Causa Pro Causa

This is the generalized 'cause and effect' error. A good explanation is provided at Fallacy Files, which separates Non Causa Pro Causa into two classes of errors, based on events and types.

We can and often do mistake coincidence for cause and effect when looking at events. However, two events happening even repeatedly in the same relation to one another in time or space may be caused by some third event of which we aren't aware. We can also get the cause and effect reversed. The cause we identify may be only the end of a domino chain of causes and effects. And the events actually may be totally unrelated except in the way we observe them.

We can also mistakenly assume that because one event of type C generally causes another event of type E, that a particular event c caused a given event e. For instance, we know that shooting a gun can cause a wound, but that doesn't mean that Johnny shooting his gun caused Freddy's wound, even if they were in the same vicinity at the time of Johnny's gunshot. Someone else could have shot Freddy, Johnny may have been shooting at Freddy's assailant (so that Freddy's wound was the cause of Johnny's shot), or Freddy's wound may not even be a gunshot wound.

Related:
Cum Hoc Ergo Propter Hoc - "with this, therefore because of this"
Post Hoc Ergo Propter Hoc - "after this, therefore because of this"
Texas Sharpshooter - assuming a cluster of data points must have a cause

Argumentum ad hominem

Latin for: Argument at the man

An "ad hominem" attack is one against a person or group who has stated an idea, rather than the idea itself. Usually, an argumentum ad hominem is attacking a source or authority for information.

As Fallacy Files says, "Argumentum ad hominem also occurs when someone's arguments are discounted merely because they stand to benefit from the policy they advocate."

An argument can be valid or invalid no matter who makes it. A special case of this general principle is that in court, known perjurers may have an impossibly difficult burden of proof to carry, and in fact their testimony may be ruled inadmissible, especially if the perjury occurs during the case at hand.

Ad hominem arguments may often be restated in better form, as changing "You're a socialist." into "What you have expressed is socialist dogma." It still needs work, since there may not be a clear relationship between the former ad hominem target's words and socialist dogma, and there is a need to overcome the burden of proving socialist dogma to be invalid, since some may find socialist dogma to be wholly reasonable.

A special case of ad hominem is the ad hominem tu quoque, in which an argument is attacked because its proponents fail (or failed in the past) to show full adherence to it themselves.

[Updated 7/15/07 for formatting, conversion to search links, and the like.]

Reductio Ad Absurdum

Reduction to the Absurd
Proof By Contradiction

Reductio ad absurdum is sometimes used fallaciously, using a poorly constructed chain of reasoning from the target proposition. It is itself a perfectly good technique, being an application of the hypothetical syllogistic form

If A, then B.
Not B.
Therefore, not A.


A → B
Not B
∴ Not A

... where B includes a chain of one or more items. Any argument may be explored to find resulting contradictions which, the reasoning being valid, show one or more of the premises to be false.

The fallacious uses of reductio ad absurdum come about by using weak or fallacious reasoning as proposition B.

Philosophy Pages

A method of proving that a proposition must be false [or true] by assuming the truth [or falsity] of the proposition and then showing that this assumption, taken together with other premises whose truth is already established, would lead to a contradiction (or, at least, to an obvious falsehood). This method is sometimes called indirect proof.

Cum hoc ergo propter hoc

Latin for "With this, therefore because of this".

Two events that occur together in time, space, or otherwise, need not be causally related, and in particular, colocation does not imply which one is cause and which one effect. Even if normally one type of event causes another, it is only an assumption to assert cause and effect.

For instance, if a man shoots a gun in a crowded room, and someone falls down, it doesn't mean that the gunshot hit the person, causing the fall. There could have been another gun, or the fall could have been in reaction to the noise, or the person could have tripped over the dog.

See also post hoc ergo propter hoc.

Both are special cases of non causa pro causa.

Post hoc ergo propter hoc

Latin for "After this, therefore because of this".

An event that follows another need not be caused by it, even if generally events of the first type cause events of the second.

See also cum hoc ergo propter hoc.

Both are special cases of non causa pro causa.

Accident

The fallacy of accident / Sweeping generalization / Dicto simpliciter

Google

Bruce Thompson:

The argument draws a conclusion from an over-simplistic statement of a rule. This takes two forms:

Destroying the Exception by insisting on the rule, which is called Accident, and

Destroying the Rule by insisting on the exception, which is called Reverse Accident (or in Latin, Secundum Quid).

In either case, the exception falls outside the scope of the rule--or would, if the rule were stated more accurately.

Fallacy Files:

Example:

Birds normally can fly.
Tweety the Penguin is a bird.
Therefore, Tweety can fly.

Exposition:

The fallacy of Accident, one of Aristotle's thirteen fallacies, has been interpreted in various ways by subsequent logicians, perhaps because of the obscurity of The Philosopher's account. I will discuss only one of these interpretations here, due to its relation to recent developments in logic.

Consider the generalization "birds can fly" from the example. Now, it isn't true that all birds can fly, since there are flightless birds. "Some birds can fly" and "many birds can fly" are too weak. "Most birds can fly" is closer to what we mean, but in this case "birds can fly" is a "rule of thumb", and the fallacy of Accident is a fallacy involving reasoning with rules of thumb.