jay gw said:Why are some of these 'worst' ideas so common and popular?
I think that they are superficially attractive and plausible, like the idea of corn gods controlling the corn etc. fit into what humans can understand, but when you examine them critically they fall apart.
The weird thing is that so many people just accept these ideas without examining them, or so it appears.
I should also like to nominate Cartesian Dualism
What harm has come from this idea?
Cartesian dualism posits that our bodies (including our brains) are controlled by a non-physical entity (essentially the real us) which is unbound by any physical law. As such it would be worth of nomination purely on the basis that it is a fine example of an unfalsifiable paranormal theory. It is an unparsimonious theory, failing the Occam' razor test many times over. It would also appear to be, given Descarte's obvious displays of intelligence elsewhere, to be an example of wishful thinking - the most pernicious form of self -delusion. Finally, though not exhaustively, by virtue of Descarte's name, it is a theory which is largely supported and popularised on the basis of an appeal to authority. All in all, it is a powerful and pervasive example of the perpetuation of irrational thought and is there really anything more harmful in philosophy?
Edited, because the crucial "I should like to nominate Cartesian dualism" phrase did not appear in the quote for some reason.