Monday, June 29, 2009

logical fallacies, no more analogies

It's come to my attention recently that analogies are considered logical fallacies. I was looking for a bit more information on the subject - all analogies? Some analogies? Is there a Latin term for it? - and came across The Fallacy Files instead.

According to the site, only weak analogies are logical fallacies. This wasn't really the answer I was hoping for, at least not without a reliable way to determine whether a given analogy is strong or weak.

I've decided to err on the side of caution. I'm not going to use analogies at all, at least for a while. I suspect they have no real place in logical discussion - as a literary tool, ok, or a teaching tool, but not to lever an argument in one direction or another.

And in the meanwhile, click through this link for a nifty diagram of logical fallacies, with lots of nifty, colorful names - like the Tu Quoque (so little known that it's certain to derail an argument, if cited), or the Hot Hand Fallacy (with a name like that, doesn't it deserve a test drive?).

1 comment:

Jacob said...

Hume had a lot of fun poking holes in other people's fallacious analogies. My favorite story is when he was once confronted with the age-old argument-from-design, which goes back many, many centuries: His opponent asserted that the universe is so complex and functionally consistent that it's like a giant clock, and just as every clock has a sentient designer, so too must the universe.

(I suppose that, when taken to its ultimate logical conclusion, this argument could actually be extended to show that the purported designer of the universe, like all real watchmakers, must himself have had parents, grandparents, and so forth. But it's hardly worth spending the time to make light of these sorts of theological inconsistencies that are endemic to the argument-from-design.)

Hume's response to his opponent was that a kangaroo is also complex and functionally consistent, and so, if the argument by analogy should be believed, then the universe must have arisen after two other universes had sex and procreated.

Hume's final assessment was that the only thing at all like the universe is, well, the universe, and so cosmological arguments by analogy are always going to be hopelessly weak.

I feel pretty much the same way about arguments by analogy in general, actually, especially when the subject is anything remotely complicated.