Bayer and Figdor in Salon:
“Begin at the beginning,” the King said, very gravely, “and go on till you come to the end: then stop.” — Lewis Carroll, Alice in Wonderland
We begin by suggesting a framework of secular belief. It begins with the simple question, How can I justify any of my beliefs? When thinking about why we believe in anything, we quickly realize that every belief is based on other preexisting beliefs. Consider, for example, the belief that brushing our teeth keeps them healthy. Why do we believe this? Because brushing helps removes plaque buildup that causes teeth to decay. But why do we believe plaque causes decay? Because our dentists, teachers, and parents told us so. Why do we trust what our dentist says? Because other dentists and articles and books we’ve read confirmed it. Why do we believe those accounts? Because they presented many more pieces of information confirming the link between plaque, bacterial growth, and tooth decay. And why do we believe those pieces of information?
There seems to be no end. It’s like the old story of a learned man giving a public lecture in which he mentions that the earth orbits the sun. At the end of the lecture an elderly lady approaches the lectern and sternly informs him that he is wrong: The world, she says, is actually resting on the back of a giant turtle. The learned man smiles and asks, “What is the turtle standing on?” The old lady doesn’t even blink and replies, “Another turtle, of course!” When the learned man starts to respond, “And what is that turtle—” she interrupts him: “You’re very clever, young man . . . but it’s turtles all the way down!” Just like that cosmic stack of turtles, the process of justifying beliefs based on other beliefs never ends—unless at some point we manage to arrive at a belief that doesn’t rely on justification from any prior belief. That would be a foundational source of belief.