The Mudcat Café TM
Thread #125317   Message #2774781
Posted By: HuwG
27-Nov-09 - 06:45 AM
Thread Name: BS: 'ex cathedra' - it means...........
Subject: RE: BS: 'ex cathedra' - it means...........
A few other fallacies to produce when in dispute:

Argument from authority A statement is true because X, an authority in that area, says so. The authority must nevertheless produce proof that the statement is true. Of course this doesn't work if the argument is "the statement is true, because this work by X displays the proof." And of course, taken to literal extremes, one cannot take anything for granted; even that one exists. Who says so?

Appeal to sentiment 99 percent of our sample believe in X. They may believe in X, but that's rather that they wish to believe in X.

Argumentum ad ignoriantiam A statement is true because no evidence exists to contradict it. Perhaps there is not; but nothing contradicts the existence of dragons, UFOs etc.

Petitio principii circular argument; the premises are true only if the conclusion is true.

Fallacious composition (or "undistributed middle term").

Socrates is a man.
All men are mortal.
Therefore, Socrates is mortal.

Impeccable! But:

O'Brien is an Irishman.
I know some Irishmen who are belligerent drunkards.
Therefore, I wouldn't trust O'Brien near a bottle.

fails, because not all Irishmen are as described.

Fallacious division the opposite of fallacious composition; the assumption that what is true of the whole must be true of the constituents.

Joe is an American
The United States of America is a wealthy country.
Let's mug him!

Joe may be wealthy, or a down-and-out.

Ignorantio elenchi begging the question; proving a conclusion irrelevant to the discussion. I can prove that Football club A is wealthier than Football club in B, but I have not proved that A is better than B in terms of results or statistics.