TO EXPLAIN THE WORLD

Histories of science celebrate great thinkers of the past. In this ingenious account, theoretical physicist and Nobel laureate Weinberg (Chair in Science/Univ. of Texas; Lectures on Quantum Mechanics, 2012, etc.) celebrates generously but gives equal emphasis to why they often missed the mark.

Many people assume that pre-Enlightenment societies were ignorant, but they didn’t think so. In ancient China, Greece, Rome and the medieval world, wise men observed, thought deeply, and pronounced on a wide variety of subjects, sometimes correctly, usually not. They not only didn’t know what they didn’t know; they also didn’t know how to learn it. They often mixed metaphysics and reality. The work of Aristotle, the quintessential ancient scientist, was suffused with teleology, the belief that everything has a purpose. Thus, objects fall because their natural place is the center of the universe. Much early science was actually philosophy, but since nothing in the laws of nature “corresponds to ideas of goodness, justice, love, or strife…we cannot rely on philosophy as a reliable guide to scientific understanding.” Despite today’s scientific orthodoxy, we also should not rely solely on observation and experiments. Copernicus and Kepler argued for a heliocentric solar system based on mathematical simplicity, not accuracy, and prediction of planetary movements was no better than Ptolemy’s. Unlike some academics, the author has a keen understanding of the precise details of his subject, and he makes good use of them throughout the book. “Some historians of science make a shibboleth of not referring to present scientific knowledge in studying the science of the past,” he writes. “I will instead make a point of using present knowledge to clarify past science.”

While Weinberg confines most mathematics to a 95-page appendix, readers will strain to comprehend some of the lengthy nuts-and-bolts explanations, but those who persist will come away with a stimulating view of how humans learn from nature.