Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

by Steven Weinberg

I would reply first that different questions are interesting in different ways. Certainly questions about creativity and life are interesting because we are alive and would like to be creative. But there are other questions that are interesting because they carry us closer to the point of convergence of our explanations. Discovering the source of the Nile did nothing to illuminate the problems of Egyptian agriculture, but who can say that it was not interesting? Also, it misses the point of this sort of question to speak of explaining the whole “in terms of the parts”; the study of quarks and electrons is fundamental not because all ordinary matter is composed of quarks and electrons but because we think that by studying quarks and electrons we will learn something about the principles that govern everything. (It was an experiment using electrons fired at the quarks inside atomic nuclei that clinched the case for the modern unified theory of two of the four fundamental forces of nature, the weak and electromagnetic forces.) In fact the elementary particle physicist today gives more attention to exotic particles that are not present in ordinary matter than to the quarks and electrons that are, because we think that right now the questions that need to be answered will be better illuminated by studying these exotic particles.