I continue to enjoy moments when, briefly, scientists admit that science is not a edifice of knowledge, unified and expanding, but a series of provisional discoveries which may or may not bear fruit. Here's an example of that.
Dean Kamen, the inventor, once said, "Don't tell me it's impossible," he says, "tell me you can't do it." "Tell me it's never been done. Because the only real laws in this world-the only things we really know-are the two postulates of relativity, the three laws of Newton, the four laws of thermodynamics, and Maxwell's equation-no, scratch that, the only things we really know are Maxwell's equations, the three laws of Newton, the two postulates of relativity, and the periodic table. That's all we know that's true. All the rest are man's laws..."
-From Esquire profile titled "How Dean Kamen's Magical Water Machine Could Save the World", December 2008.
I learned to watch for this "but it's all a unified edifice, and if you disturb one logical link or deny one metaphor, it all falls apart" as I studied philosophy in the Roman period. This was a time when a lot of people fell prey to the "if it's a unified system, it must be right" theory of knowledge. There are still people who say, "But if you don't believe in X, then how do you cross the street? Doesn't it all logically depend on that?"
Of course not.