Bubbles vs delusion
Wasn't MacKay's point that the tulip speculators were deluded, in believing the value of tulip bulbs would always rise, or at least that they were smart enough to cash in before everyone else if they did realise it was crazy. I don't know what this is if it isn't a delusion, and it had to be a mass delusion as it required enough people to support the market and provide the groupthink that tulips were a sensible investment.
MacKay maybe meant that speculative bubbles were caused by delusion, a flaw in human minds where people believe what they want to believe, no matter how irrational. I know I can easily delude myself if I'm not careful, just to avoid having to be disappointed, or looking stupid. Of course you feel stupider in the end for having been deluded. If enough people share a delusion about rising prices or that they will know when it will peak before everyone else, then it is a mass delusion. And they will reject anyone who doesn't share it to protect themselves. 'If that guy is right, that means I am not only stupid, but deluded and stupid, and ruined, so he's not right, in fact he is the crazy one!!' And so it keeps going. Tombo1bo (talk) 20:22, 21 February 2013 (UTC)