Recently, I received an e-mail forward that claimed that 9/11 was a conspiracy hatched by the US government and its agencies. It urged me to follow a link that had irrevocable evidence to the fact. I prudently deleted the email, and did not follow the link. However, I think understanding economics and the power of incentives leads me to dismiss any such conspiracy theories. If we look at the number of scandals that have been breaking out in recent years, it is far fetched to believe that a large group of people can keep their mouth shut for long periods of time. Mancur Olson argued in the Logic of Collective Action that unless the number of individuals was small, or there was coercive force, a group of individuals cannot be persuaded to act in their collective interest. Assuming, a conspiracy as big as 9/11 would have involved hundreds of people, I do not think it would be possible to swear them all to an oath of secrecy. I do not think so many citizens would be willing to kill thousands of their own. Yes! There are individual murderers, but its beyond imagination that so many American citizens would want their own dead. Even with genocide and terrorism it is a targeted population outside the social group of the attacker, and we may say that some of the prejudices that individuals held are fuelled by a persuasive leader. However, 9/11 affected a diverse group of people of different nationalities (primarily US citizens), ethnicities, religions, and trades. Even if some of the people involved in the conspiracy had a general prejudice I doubt that hundreds or even dozens of people would have held similar beliefs. Logically, to me, it does not seem possible that 9/11 was a conspiracy hatched by someone in the US government against their own citizens. It was a terrorist attack hatched by some fanatics.