On Wed, 10 Feb 2010 01:38:50 +0100 "Alf P. Steinbach" <al...@start.no> wrote: > However, although in this particular case the Ad Hominems constituted logical > fallacies, not all Ad Hominems are logical fallacies.
Yes they are. Using the reputation of someone to prove or disprove their claims is a logical fallacy. > For example, if a person is a chronic liar, has a known history of lying, > then > that can have a strong bearing on whether the person's claims -- technical > or > about other persons -- should be seriously considered[1]. Yes but it's still a fallacy. Taking the author's history into account may be valid for deciding that further investigation is warranted but by itself it does not prove anything about the claims. Suggesting that it does is fallacious. "Bill is a liar therefore his statement is false" is a fallacy. "Bill is a liar so take his claims with a grain of salt" is not. There is another case. "Bill never tells the truth therefore his claim is wrong" is not an ad hominem fallacy. It's a sylogism. It may or may not be correct but if the first statement is true (Bill always lies) then the the conclusion is true. -- D'Arcy J.M. Cain <da...@druid.net> | Democracy is three wolves http://www.druid.net/darcy/ | and a sheep voting on +1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
