This season's fashion in conspiracy theories—for those out of the loop of enlightenment—concerns health. The Web sites, marginal cable shows and radio phone-ins are full of tales about how Big Pharma and Bad Government are deliberately spreading diseases or manufacturing scares in order to sell us expensive drugs, gull us into dangerous vaccinations or just simply to create an atmosphere of panic which will allow "them" to take over.

Swine flu? The disease was created in a lab by a shadowy company, which had associations...