Most skeptics I talk to think they operate completely without bias in their skepticism and agnosticism. They often demonstrate a startling lack of self-awareness of their assumptions. One hundred years ago, the British essayist G. K. Chesterton noted the frustrating contradiction of the skeptics arguments:

“I remember once arguing with an honest young atheist, who was very much shocked at my disputing some of the assumptions which were absolute sanctities to him (such as the quite unproved proposition of the independence of matter and the quite improbable proposition of its power to originate mind), and he at length fell back upon this question, which he delivered with an honourable heat of defiance and indignation: “Well, can you tell me any man of intellect, great in science or philosophy, who accepted the miraculous?” I said, “With pleasure. Descartes, Dr. Johnson, Newton, Faraday, Newman, Gladstone, Pasteur, Browning, Brunetiere—as many more as you please.” To which that quite admirable and idealistic young man made this astonishing reply—’Oh, but of course they had to say that; they were Christians.’

“First he challenged me to find a black swan, and then he ruled out all my swans because they were black. The fact that all these great intellects had come to the Christian view was somehow or other a proof either that they were not great intellects or that they had not really come to that view. The argument thus stood in a charmingly convenient form: ‘All men that count have come to my conclusion; for if they come to your conclusion they do not count.’“