Almost at once the Bogdanov paper excited debate among physicists as to whether it was twaddle, a work of genius, or a hoax. "Scientifically, it's clearly more or less complete nonsense," Columbia University physicist Peter Woit told the New York Times, "but these days that doesn't much distinguish it from a lot of the rest of the literature."
Karl Popper, whom Steven Weinberg has called "the dean of modern philosophers of science," once suggested that there may not be an ultimate theory for physics—that, rather, every explanation may require a further explanation, producing "an infinite chain of more and more fundamental principles." A rival possibility is that such knowledge may simply be beyond us. "So far, fortunately," writes Weinberg in Dreams of a Final Theory, "we do not seem to be coming to the end of our intellectual resources."
Almost certainly this is an area that will see further developments of thought, and almost certainly these thoughts will again be beyond most of us.
While physicists in the middle decades of the twentieth-century were looking perplexedly into the world of the very small, astronomers were finding no less arresting an incompleteness of understanding in the universe at large.
When we last met Edwin Hubble, he had determined that nearly all the galaxies in our field of view are flying away from us, and that the speed and distance of this retreat are neatly proportional: the farther away the galaxy, the faster it is moving.