I used to think of skepticism as a primary intellectual virtue, whose goal was truth. I have changed my mind. I now see it as a weapon.
Creationists opened my eyes. They use the techniques of critical thinking to expose weaknesses in the evidence for natural selection, gaps in the fossil record and problems with evolutionary theory. Is this because they are seeking truth? No. They believe they already know the truth. Skepticism is a weapon to defend their beliefs by attacking their opponents.
Skepticism is also an important weapon in the defence of commercial self-interest. According to David Michaels, who was assistant secretary for environment, safety and health in the US Department of Energy in the 1990s, the strategy used by the tobacco industry to create doubt about inconvenient evidence has now been adopted by corporations making toxic products such as lead, mercury, vinyl chloride, and benzene. When confronted with evidence that their activities are causing harm, the standard response is to hire researchers to muddy the waters, branding findings that go against the industry's interests as "junk science." As Michaels noted, "Their conclusions are almost always the same: the evidence is ambiguous, so regulatory action is unwarranted." Climate change skeptics use similar techniques.
In a penetrating essay called "The Skepticism of Believers", Sir Leslie Stephen, a pioneering agnostic (and the father of Virginia Woolf), argued that skepticism is inevitably partial. "In regard to the great bulk of ordinary beliefs, the so-called skeptics are just as much believers as their opponents." Then as now, those who proclaim themselves skeptics had strong beliefs of their own. As Stephen put it in 1893, " The thinkers generally charged with skepticism are equally charged with an excessive belief in the constancy and certainty of the so-called 'laws of nature'. They assign a natural cause to certain phenomena as confidently as their opponents assign a supernatural cause."
Skepticism has even deeper roots in religion than in science. The Old Testament prophets were withering in their scorn for the rival religions of the Holy Land. Psalm 115 mocks those who make idols of silver and gold: "They have mouths, and speak not: eyes have they, and see not." At the Reformation, the Protestants deployed the full force of biblical scholarship and critical thinking against the veneration of relics, cults of saints and other "superstitions" of the Catholic Church. Atheists take religious skepticism to its ultimate limits; but they are defending another faith, a faith in science.
In practice, the goal of skepticism is not the discovery of truth, but the exposure of other people's errors. It plays a useful role in science, religion, scholarship, and common sense. But we need to remember that it is a weapon serving belief or self-interest; we need to be skeptical of skeptics. The more militant the skeptic, the stronger the belief.