The hidden superstrings, these thinkers went on, are the ultimate stuff of existence, forming us from the void by their tireless (and pretty much unexplained) rapid spinning, which surrounds each mass-less string with a sort of wall. The folded-up dimensions are at once incomprehensibly little, yet bulwarks; what they are is so alien to our existence that we'll never know, but add them all up like ingredients and you get solid matter.

Some scientists see superstring ideas as slight of hand or even hooey; priests of the middle ages, the theory's opponents are fond of pointing out, tried to explain forces of nature using mumbo-jumbo about the invisible too. But many physicists like superstring thinking, because it offers at least a conceptual explanation for one of the greatest of all questions: Why is there anything, instead of nothing?

What is haunting about the juxtaposition of superstring theory and theology is that both describe the unseen as ultimately responsible for our being. Maybe superstrings are real but arise wholly from natural forces; maybe they are real and were made by God; maybe the idea will be discarded. At any rate, hundreds of advanced physicists now believe that invisible planes of existence are everywhere around us, maybe by the dozens. Is it so hard, in that context, to believe there is one real but invisible plane of the spirit?