the_ideas

Common Logical Fallacies

Appeal to authority—An appeal to authority is ordinarily one good way to buttress a line

of thought. The practice becomes fallacious when one of the following happens: the

authority is not an expert in the field in which one is speaking; the allusion to authority

masks the fact that experts may be divided down the middle on the subject; no explicit

reference is made to the authority.

Attack against the person—A common fallacy in which someone argues against a

position or claim by assailing the proponent of it. The truth or falsehood of a position

doesn't depend on who does (or doesn't) espouse it. e.g. "You can't trust Jones' theory of

electromagnetic particles because he's a communist." (The theory is good or bad because

it comports (or doesn't comport) with certain facts and evidence, not because the man

propounding it holds a political affiliation.)

Appeal to Pity -- Occurs when an appeal is made to pity or to one's sympathetic nature.

Example: "Augusto Pinochet is an old, dying man. It is wrong to make him stand trial for

alleged offenses."

Bandwagon Appeal -- This fallacy occurs when an argument panders to popular passion

or sentiment. When, for instance, a politician exclaims in a debate that his opponent "is

out of step with the beliefs of everyone in the audience," he/she is committing the fallacy.

The legitimacy of a statement depends not on its popularity, but on its truth credentials.

Begging the question -- Circular reasoning in which a claim is assumed to be true and is

then tucked in the conclusion. e.g. "Government by the people is ideal because

democracy is the least inadequate form of government." ("Government by the people" is

the working definition of democracy; the first part of the statement needs to be proven,

not reasserted in the predicate.)

False alternatives -- A fallacy occurring when the number of alternatives is said to be

fewer/less than the actual number. Common examples of this fallacy are statements

containing either/or, nothing/but, all-or-nothing elements. Examples: "Is she a Democrat

or a Republican?" (She may be a socialist, a libertarian, a Leninist, an anarchist, a

feminist or any number of other things, including one who is strictly apolitical.) "If you

aren't for your country, then you are against it." (One may be neither "for" nor "against"

but may occupy a position of strict neutrality or be affirmative sometimes and critical at

others.)

False Cause—The fallacy of reaching a conclusion based solely on the sequence of

events. Implying causation when no good reason is given for doing so. “The Soviet

Union collapsed after adopting atheism. Therefore, we must avoid atheism or we also run

the risk of collapse.”

Hasty generalization -- The habit of arriving at a bold conclusion based on a limited

sample of evidence. This often occurs with statistics. For instance, someone may ask ten

women and one man what their opinion is of contemporary male-female relationships and

from this sample draw a sweeping conclusion; hasty generalization would then be said to

exist.

Invincible ignorance -- the fallacy of insisting on the legitimacy of one's position in the

face of contradictory facts. Statements like "I really don't care what the experts say; no

one is going to convince me that I'm wrong"; "nothing you say is going to change my

mind"; "yeah, okay, whatever!" are examples of this fallacy.

Non sequitur ("it does not follow") -- A statement that does not logically follow from

what preceded it—a conclusion that does not follow from the premises. “Because Jane

Smith is a brilliant historian she must be a brilliant history teacher.”

Prejudicial Language value or moral goodness is attached to believing the author. Loaded

language is emotive terminology that expresses value judgments. When used in what

appears to be an objective description, the terminology unfortunately can cause the

listener to adopt those values when in fact no good reason has been given for doing so.

[News broadcast] In today's top stories, Senator Smith carelessly cast the deciding vote

today to pass both the budget bill and the trailer bill to fund yet another excessive

watchdog committee over coastal development.—This broadcast is an editorial posing as

a news report.

Red herring -- An attempt to divert attention away from the crux of an argument by

introduction of anecdote, irrelevant detail, subsidiary facts, tangential references, and the

like.

Slippery Slope a series of increasingly unacceptable consequences is drawn. The form of a slippery slope fallacy looks like this: A leads to B. B leads to C. C leads to D. ... Z leads to HELL. We don't want to go to HELL. So, don't take that first step A.

Straw man -- A fallacy that occurs when someone attacks a less defensible position than

the one actually being put forth. This occurs very often in politics, when one seeks to

derive maximum approval for himself/herself or for a cause. Example: "Opposition to the

North American Free Trade Agreement amounts to nothing but opposition to free trade."

(Someone can believe in free and open trade and yet still oppose NAFTA.)

Taken From: http://www.philosophicalsociety.com/Logical%20Fallacies.htm