The increase does not, however, tend to any strengthening of the creative faculty. There is a greater abundance of models of excellence, models of which form the taste, afford a stimulus to sensitive minds, and establish a sort of technique with well-known rules. The principles of criticism are more fully investigated. The power of analysis grows, and the appreciation both of literature and of art is more widely diffused. Their influence on the whole community becomes greater, but the creative imagination which is needed for the production of original work becomes no more abundant and no more powerful. It may, indeed, be urged, though our data are probably insufficient for a final judgment, that the finer qualities of poetry and of pictorial and plastic art tend rather to decline under the more analytic habit of mind which belongs to the modern world. Simplicity, freshness, spontaneity come less naturally to those who have fallen under the pervasive influence of this habit. [Illustration: Mansell THE MIND OF THE MEDIÆVAL WORLD St. Thomas of Aquinum, 1500 years later than Aristotle, represents mediæval thought. St. Thomas, however, influences the life and thought of many thousands to-day. ] [Sidenote: Effect of Thought on Mankind] There remains one other way in which the incessant play of thought may be said to have increased or improved the resources of mankind. Certain principles or ideas belonging to the moral and social sphere--to the moral sphere by their origin, to the social sphere by their results--make their way to a more or less general acceptance, and exert a potent influence upon human life and action. They are absent in the earliest communities of which we know, or are present only in germ. They emerge, sometimes in the form of customs gradually built up in one or more peoples, sometimes in the utterances of one gifted mind. Sometimes they spread impalpably; sometimes they become matter for controversy, and are made the battle-cries of parties. Sometimes they end by being universally received, though not necessarily put into practice. Sometimes, on the other hand, they continue to be rejected in one country, or by one set of persons in a country, as vehemently as they are asserted by another. As instances of these principles or ideas or doctrines, whatever one is to call them, the following may be taken: The condemnation of piracy, of slavery, and of treaty-breaking, of outrages on the bodies of dead enemies, of cruelty to the lower animals, of the slaughter of prisoners in cold blood, of polygamy, of torture to witnesses or criminals; the recognition of the duty of citizens to obey the laws, and of the moral responsibility of rulers for the exercise of their power, of the right of each man to hold his own religious opinion and to worship accordingly, of the civil (though not necessarily of the political) equality of all citizens; the disapproval of intoxication, the value set upon female chastity,