Posts

Showing posts with the label proof

Santa Claus does too exist!

Image
Contrary to the assertion of the scandalous propaganda on the left, Santa Claus does indeed exist. And I can prove it. Start with proposition A: A . If A is true, then Santa Claus exists. Now, suppose A were true. Then it would follow that if A is true, then Santa Claus exists , and again since we're supposing A is true, it would follow that Santa Claus exists. So we've shown that if A is true, then Santa Claus exists . But that is proposition A, so we've proven that proposition A is true. So that means that Santa Claus exists! (A remarkable conclusion given my recent post on things that probably don't exist .) The only trouble is that the reasoning above lets you prove anything (e.g. that penguins rule the universe ). It's an example of Curry's paradox , which can't be easily explained away, and is the subject of ongoing research by logicians. Bah humbug! Still not convinced? Thomas Aquinas to the rescue! Well, actually, his modern admirers. Aquinas came u...

Things that (probably) don't exist

Image
A recent article by philosopher Steven Hales is titled " You Can Prove a Negative " (a slightly different version of the article is available as a pdf file ). Hales argues that the "principle of folk logic" saying you can't prove a negative is just plain wrong . He points out that " any claim can be expressed as a negative, thanks to the rule of double negation." So it's easy to come up with examples of proving a negative. Hales goes on to say that "Some people seem to think that you can’t prove a specific sort of negative claim, namely that a thing does not exist." He counters this with an example of a valid proof that something doesn't exist: 1. If unicorns had existed, then there is evidence in the fossil record. 2. There is no evidence of unicorns in the fossil record. 3. Therefore, unicorns never existed. Of course, the difficulty here is with the truth of the premises (1 and 2). In particular, it could be that we just haven...