"It's not because we haven't found weapons of mass destruction that they don't exist".
We all remember this line by Rumsfeld back in 2003 after the invasion of Iraq by the so-called "coalition of the willing". Sounded kinda logical didn't it? And yet many felt there was another flaw in the sentence. Where or which was it?
Let's try something else : I'm having a walk with Kiki my cute little cub. It gets lost in the wood and I'm searching for it. After half an hour, I'm still looking for it and I safely can say : It's not because I haven't found it yet that it doesn't exist. Sure it exists, it was with me half an hour ago.
Another try then : It's not because I haven't found a couple of pink elephants with blue wings and three tails that they don't exist. Everyone would be more than sceptical here.
Or even : It's not because I haven't seen a second sun rising from the west in the morning that it doesn't exist. Now you'll question the mental state of your interlocutor.
Rumsfeld's sentence is all in negatives. We'll turn it into full positives like : It's because we've found weapons of mass destruction that they exist.
Anyone with a modicum of common sense will immediately react and say : It's not because you've found them that they exist. Actually,they existed prior to their location. Finding these wmd was only evidence that they indeed existed.
The trick consists of taking for granted the existence of something you're looking for, something that may exist indeed, but something which needs to be proven as really existing in any particular case.
A couple of pink elephants with blue wings and three tails may exist after all but show me one, just one.
Here again, it's a trick dealing with the basics of logics, particularly in the field of syllogism methinks, but I'm not that familiar with this discipline to exactly point out where the fraud is. Except that Rumsfeld subliminally suggested that the Major premise contained a data (existence of wmd) that should be found, if ever, in the conclusion.
[If a statement includes a term so that the statement is false if the term has no instances (is not instantiated) then the statement is said to entail existential import with respect to that term.]
I have a feeling, well, I think Rumsfeld toyed along that "existential import", whether he knew it or not.
Anyway, it can be written down and deconstructed by any student in logics by means of Aa if Bb // Ab <- aAc etc. (là c'est n'importe quoi...)
Trop forts ces Américains décidément!