Dreams of a Final Theory

The mirage of a ``Grand Unified Theory,'' which would be a final explanation of the laws of nature, tantalized Einstein 75 years ago and still shimmers just over the horizon of quantum mechanics. Weinberg, who shared a 1979 Nobel Prize (with Abdus Salam and Sheldon L. Glashow) for linking electromagnetism and the ``weak'' force, here offers a ``state of the theory'' report. His slightly elegaic tone suggests that he is attempting not only to sum up but also to pass along the quest for the ultimate vision of nature to a new generation, a goal which he admirably achieves. In his first trade book, The First Three Minutes , the author made it clear that theory in physics can be a prism of human passions. Here he describes the search for a final theory as the extreme human intellectual adventure that it is, choosing to face (as Stephen Hawking did not in A Brief History of Time ) the most radical question about nature: ``What About God?'' Weinberg frames the search for nature's final theory with an artisan's skill, a scientist's sense of wonder and an artist's love of beauty. (Jan.)