the rational justification of their society. The mediaeval scholars maintained the Greek ideal of completeness and logical consistency, their efforts culminating in the 13th century, the century of the schoolmen, one of the most intensely intellectual periods of history. The growth of scholasticism provided the occasion for long training in close, logical thinking, which, while not used upon materials that to us seem profitable, tempered the mental weapons to be used in the later battles of intellectual liberation. "To the schoolmen," J. S. Mill observes, "we owe whatever accuracy of thought and lucidity of logic we can boast."
The second stream, running through Hellenistic Alexandria, bore the only thing like experimental inquiry carried on in the classical world. The Arabs, with a pronounced predilection for this type of work, had there quickly assimilated what the Greeks had to offer on this side, as they also had important acquisitions of the Hindus at a time when interest in Nature had wholly died out in Europe. These things they introduced into the schools of southern Europe. They brought with them three world-transforming inventions—the mariner's compass, gunpowder and paper, as well as the Hindu or Arabic system of numeration, algebra, and the forerunners of modern surveying instruments, the beginnings of chemistry, and most of the ideas of the later Middle Ages at any value in mathematics, astronomy, geography, medicine and natural history.
With the reuniting of the two streams of Greek thought, both enriched by special contributions, there arose the conflict of Arabic experimentalism, with its interest in "stubborn and irreducible facts," and scholastic rationalism, with its critical acumen and Greek gift for generalization. The outcome was that balance between the two that is the scientific spirit and method; the method that provides the effective technique for getting answers to our questions from Nature.
Science first arose in and spread from the universities of southern Europe. Roger Bacon and others in the 13th and 14th centuries showed the dual heritage and exhibited the mental balance and final reliance on experiment that are the pillars of science.
With the 15th century, the change in conditions and ideals, and, above all, the slow accumulation of facts that would not be denied, produced a wide and obvious discontent with the entire mediaeval social and cosmic scheme. There were various significant movements accompanying the beginnings of science at this time and contributing circumstances that made its emergence and open, victorious career possible. I may merely mention the rise of commerce and industry, with widening freedom in economic pursuits and the spread of wealth and leisure; Columbus; Vasco da Gama; Copernicus; the expansion of universities; and the discovery of printing. The emancipation of the individual was the most important contribution of this period of the so-called Renaissance. The real rise of science coincides with the reawakening of individualism.
That universal genius da Vinci showed an almost perfect apprehension of the new method; "Those sciences are vain and full of
