The same impulses that led people in that age to explore Earth, the stellar regions, and the nature of matter led them also to explore the institutions around them: state, economy, religion, morality, and, above all, human nature itself. It was the fragmentation of medieval philosophy and theory, and, with this, the shattering of the medieval worldview that had lain deep in thought until about the 16th century, that was the immediate basis of the rise of the several strands of specialized social thought that were in time to provide the inspiration for the social sciences.

Medieval theology, especially as it appears in St. Thomas Aquinas’s Summa theologiae (1265/66–1273), contained and fashioned syntheses from ideas about humanity and society—ideas indeed that may be seen to be political, social, economic, anthropological, and geographical in their substance. But it is partly this close relation between medieval theology and ideas of the social sciences that accounts for the different trajectories of the social sciences, on the one hand, and the trajectories of the physical and life sciences, on the other. From the time of the English philosopher Roger Bacon in the 13th century, there were at least some rudiments of physical science that were largely independent of medieval theology and philosophy. Historians of physical science have no difficulty in tracing the continuation of this experimental tradition, primitive and irregular though it was by later standards, throughout the Middle Ages. Side by side with the kinds of experiment made notable by Bacon were impressive changes in technology through the medieval period and then, in striking degree, in the Renaissance. Efforts to improve agricultural productivity; the rising utilization of gunpowder, with consequent development of guns and the problems that they presented in ballistics; growing trade, leading to increased use of ships and improvements in the arts of navigation, including use of telescopes; and the whole range of such mechanical arts in the Middle Ages and Renaissance as architecture, engineering, optics, and the construction of watches and clocks—all of this put a high premium on a pragmatic and operational understanding of at least the simpler principles of mechanics, physics, astronomy, and, in time, chemistry.

In short, by the time of Copernicus and Galileo in the 16th century, a fairly broad substratum of physical science existed, largely empirical but not without theoretical implications on which the edifice of modern physical science could be built. It is notable that the empirical foundations of physiology were being established in the studies of the human body being conducted in medieval schools of medicine and, as the career of Leonardo da Vinci so resplendently illustrates, among artists of the Renaissance, whose interest in accuracy and detail of painting and sculpture led to their careful studies of human anatomy.

Very different was the beginning of the social sciences. In the first place, the Roman Catholic Church, throughout the Middle Ages and even into the Renaissance and Reformation, was much more attentive to what scholars wrote and thought about the human mind and human behaviour in society than it was toward what was being studied and written in the physical sciences. From the church’s point of view, while it might be important to see to it that thought on the physical world corresponded as far as possible to what Scripture said—witnessed, for example, in the famous questioning of Galileo—it was far more important that such correspondence exist in matters affecting the human mind, spirit, and soul. Nearly all the subjects and questions that would form the bases of the social sciences in later centuries were tightly woven into the fabric of medieval Scholasticism, and it was not easy for even the boldest minds to break this fabric.

Then, when the hold of Scholasticism did begin to wane, two fresh influences, equally powerful, came on the scene to prevent anything comparable to the pragmatic and empirical foundations of the physical sciences from forming in the study of humanity and society. The first was the immense appeal of the Greek classics during the Renaissance, especially those of the philosophers Plato and Aristotle. A great deal of social thought during the Renaissance was little more than gloss or commentary on the Greek classics. One sees this throughout the 15th and 16th centuries.

Second, in the 17th century there appeared the powerful influence of the philosopher René Descartes. Cartesianism, as his philosophy was called, declared that the proper approach to understanding of the world, including humanity and society, was through a few simple, fundamental ideas of reality and, then, rigorous, almost geometrical deduction of more complex ideas and eventually of large, encompassing theories, from these simple ideas, all of which, Descartes insisted, were the stock of common sense—the mind that is common to all human beings at birth. It would be hard to exaggerate the impact of Cartesianism on social and political and moral thought during the century and a half following publication of his Discourse on Method (1637) and his Meditations on First Philosophy (1641). Through the Enlightenment into the later 18th century, the spell of Cartesianism was cast on nearly all those who were concerned with the problems of human nature and human society.

Great amounts of data pertinent to the study of human behaviour were becoming available in the 17th and 18th centuries. The emergence of nationalism and the associated impersonal state carried with it ever growing bureaucracies concerned with gathering information, chiefly for taxation, census, and trade purposes. The voluminous and widely published accounts of the great voyages that had begun in the 15th century, the records of soldiers, explorers, and missionaries who perforce had been brought into often long and close contact with indigenous and other non-Western peoples, provided still another great reservoir of data. Until the beginning of the 19th century, these and other empirical materials were used, if at all, solely for illustrative purposes in the writings of the social philosophers. Just as in the equally important area of the study of life, no philosophical framework as yet existed to allow for an objective and comprehensive interpretation of these empirical materials. Only in physics could this be done at the time.