For more Ridley, listen to his October 2011 lecture on "Scientific Heresy." Ridley asks:
How do you know whether you are taking the rational or the irrational side of an argument, the scientific or the pseudoscientific position? Or to put it a slightly different way, when are the heretics right and when are they nutcases? This question is not as easy to answer as it seems.
Many scientific truths began as heresies and fought long battles for acceptance against entrenched establishment wisdom that now appears irrational: the germ theory, continental drift, the use of antibiotics to treat stomach cancer, low-carbohydrate diets, even the idea that crop circles are man-made. Many environmentalists think the scientific conventional wisdom is right about climate change, and explicitly demand obedience to the consensus or even argue that dissent is illegitimate, but at the same time many of the same people once argued that scientific conventional wisdom is wrong about the safety of genetically modified food and that dissent is legitimate.
There is a consensus that the earth is round and natural selection explains evolution, but there is also a consensus that ghosts and gods exist. So the consensus cannot always be trusted, but nor can it always be dismissed. This lecture will explore the problem of how to decide when to question the scientific wisdom and when to accept it.