SCIENCE, like most things, was gradual in its beginnings, and it was not until the seventeenth century that it began to acquire a decisive position. It has since grown to be the most distinctive characteristic of our age; for good or evil, it is what makes our age different from antiquity and the medieval centuries.
Science may be defined as the discovery of causal laws by means of observation and experiment—laws which are more valued when they are quantitative than when they are merely qualitative. Mathematics, which does not require observation, owes its first considerable development to the Greeks, but the only observational study in which the Greeks were proficient was astronomy, where there are very obvious uniformities and much can be done by pure geometry. It was not until Galileo that a way was found of dealing with motions that are not uniform and not periodic. Before his time men sought laws of stability; but in modern times laws of change have been what science has mainly wished to find. And ever since Bacon science has been valued, not only, or even chiefly, as pure knowledge, but as a source of power—power over inanimate nature, power over plants and animals, and now, at last, power over human communities.
Science is a product of Europe. The only exception I can think of is the Babylonian discovery that eclipses could be predicted. A very few nations—Italy, France, the Low Counties, Britain, and Germany—contributed not quite 90 percent of the great discoverers. Poland contributed Copernicus, Russia contributed Mendeleeff and Pavlov, but on the whole the share of Eastern Europe has not been a great one. Within Western Europe, as may be seen from a map showing the birthplaces of eminent men of science, there has been a correlation with commerce and industry. But commerce does not necessarily lead to science. It did not do so among the Phoenicians and Carthaginians, and the Arabs, though they studied science of a sort, made no discoveries in any way comparable to those of Western Europe since 1600. I do not think that seventeenth century science can be regarded as an inevitable outcome of social and economic conditions; the existence of individuals possessed of very rare abilities was also necessary. Why they should have been born there and then cannot be explained in scientific terms by means of our present knowledge. It certainly does not have a racial explanation, as may be seen from the fact that many of the best men of science have been Jews, who though living in Europe are not of course of Western European stock.
The importance of the economic conditions which attended the beginnings of modern science has been so much emphasized that the intellectual conditions have tended to be overlooked. Let us spend a few moments in considering scientific method in itself, apart from the social environment that promoted it.
The essential matter is the intimate association of hypothesis and observation. The Greeks were fruitful in hypotheses, but deficient in observation. Aristotle, for example, thought that women have fewer teeth than men, which he could not have thought if he had had a proper respect for observation. Francis Bacon, on the other hand, overestimated the mere collecting of facts, supposing that this, if carried far enough, would of itself give rise to fruitful hypotheses. But there are so many facts, and so many ways of arranging facts, that no one can collect facts usefully except under the stimulus of some hypothesis to which they are relevant. Throughout any scientific investigation, even from the very beginning, generalizing hypotheses must exist in the mind of the investigator to determine the direction of his observations. The hypothesis must, however, continually change and develop as new facts prove old hypotheses to be inadequate.
It is commonly said that the framing of hypotheses is the most difficult step in scientific investigation, and perhaps this is true of men who have undergone a thorough education in science. But viewed historically it would seem that respect for fact is more difficult for the human mind than the invention of remarkable theories. It is still believed by a large percentage of the inhabitants of this country that people born in May are specially liable to corns, that the moon affects the weather, and that it is dangerous to se the new moon through glass. None of those who hold these theories think it necessary to verify them. Aristotle’s physics, as interpreted by medieval commentaries, supplied a number of admirable theories, which covered the ground much more adequately than Galileo could do. There was nothing against the theories except that they were not in accordance with the facts, but this objection struck Galileo’s Aristotelian adversaries as frivolous. And when he discovered Jupiter’s moons, their existence was denied on the ground that the number of the heavenly bodies must be seven. I think, therefore, that in the beginning the respect for fact demanded by science is more difficult even than the framing of what may prove good hypotheses. And the hypotheses that prove good are very seldom such as commend themselves to our initial prejudices.
As against Bacon, the history of science seems to show that even the worst hypothesis is better than none. The beginnings of chemistry were dominated by the search for the philosopher’s stone and for means of turning base metals into gold. This search supplied an essential element in scientific method which was absent in astronomy—I mean experiment as opposed to passive observation. If the medieval alchemists had not had extravagant hopes, they would not have had the patience to accumulate gradually a great mass of facts which could only become known by the artificial creation of conditions not spontaneously produced by nature. This work, which the Arabs took over from Alexandria and the Christians from the Arabs, supplied much detailed knowledge, but did not yield anything scientifically systematic until the time of Lavoisier and Priestley at the end of the eighteenth century. And it was not until our own day that the diversity of chemical elements was fitted into an unitary theory, and that the transmutation of elements became a practical possibility—with consequences that, if not controlled, threaten disaster to mankind.
The prejudices against scientific investigation of facts has been strongest where human beings are concerned. Throughout the middle ages anatomy was hampered by a rooted objection to dissection of corpses. Vesalius, who was court physician to Charles V and Philip II, ventured, under the protection of royal favor, to defy this prejudice. But his enemies accused him of having dissected a body while still alive, and he was sentenced, as a penance, to a pilgrimage to the Holy Land. During his return, he was shipwrecked and died of exposure. In China, not many years ago, a French surgeon, who had been invited to found a medical school, demanded corpses for dissection. He was told that to cut up corpses would be an impiety. These two opposite stories both illustrate the obstacles to a scientific outlook.
Western Europeans, and men in the New World whose ancestors, whatever their racial origin, had lived in Western Europe, had for about three centuries a virtual monopoly of science, and acquired thereby a supremacy throughout the world such as neither they nor anyone else and possessed at any earlier time. This monopoly, of course, could not last for ever. Although the Japanese challenge proved unsuccessful, European domination in Asia is disappearing, and we may expect a growth of Asiatic science as a result of political independence. Now that scientific method has been developed, a great deal can be achieved without the genius that was necessary in the pioneers. Any man possessed of patience and fair abilities and the necessary equipment can, nowadays, be pretty sure to find out something, and it may happen to be something of great importance. I do not think that Mendel’s work required any very extraordinary gifts, and yet the Mendelian theory of heredity is transforming scientific agriculture and stockbreeding, and probably will in time considerably alter the congenital character of human beings. The more science advances, the easier it becomes to make new discoveries; that is why the rapidity of scientific progress has been continually increasing since the seventeenth century.
Science has been victorious over the prejudices that opposed its progress, because it has conferred power, and especially power in war. Archimedes, almost the only experimental scientist among the Greeks, was useful in the defence of Syracuse. Leonardo da Vinci was employed by the Duke of Milan because he understood the science of fortification. Galileo, similarly, was supported by the Grand Duke of Tuscany because his researches on projectiles showed how to make artillery more effective. In the French Revolution, French men of science played a vital part in the defence of their country against its many enemies. In the recent war it was scientific superiority that secured the final defeat of Japan. For such reasons, there is now little active opposition to scientific technique and scientific methods of investigation.
But power without wisdom is dangerous, and what our age needs is wisdom even more than knowledge. Given wisdom, the power conferred by science can give a new degree of well-being to all mankind; without wisdom, it can bring only destruction.