Science and magic are very unlike, but even the distinction between East and West varies according to where the speaker takes his stand. We have come to regard science as abstract truth, scientific investigation as necessarily correct and sensible; we forget that science has a past. In their actual history science and magic were not unassociated. Scientists might accept magical doctrines and magic might endeavor to classify its fancies and to account for them by natural causes. Roger Bacon could regard the attainment of magical results as the great end of experimental science. Francis Bacon could place magic in the same category with metaphysics and physics. It is with this mingling of magic and science—or more broadly of magic with learning in general—in the history of our Western world that this essay has to do. It is a theme of no narrow interest. Such ideas as have been cited, not only held by the most learned men of the times but incorporated in their scientific and philosophical systems—in so far as they had any—deserve consideration in the history of science and philosophy as well as in that of magic, or in an investigation of the mental make-up of the men of the past. While, however, the place of magic in the intellectual history of Europe is our general subject, the present essay is far from being an attempt at a complete treatment of it. The aim is rather to illustrate that theme by a survey of learning during the period of the Roman Empire, when the divers threads of the thought and knowledge of the ancient world were to some extent united. The prominence of magic in mediæval science is perhaps better known and more generally admitted. Accordingly this essay will take for granted, except in so far as it has been illustrated in our first chapter, the presence of magic in mediæval learning, and will try to show that magical doctrines, credulity, mysticism, and love of the marvelous were not traits peculiar to mediæval thought, but that in this respect (as in others) there was close resemblance, probably strict continuity between the Roman world and later times. It was largely in order to bring out this resemblance, continuity and influence that the beliefs of various writers in the Middle Ages and early modern times were given in the first chapter. Let the reader compare them with those notions of men in the Roman Empire which will presently be set forth. If we are justified in thus regarding the Roman world as summarizing ancient science and helping to explain mediæval thought, we evidently, in taking our stand in that period secure a broad prospect and ought to obtain a fair idea of the place of magic in the intellectual history of Europe. In defining the field which we are to cover, it should be further said that Christian thought will not come into our discussion, since it did not greatly influence science and other secular learning until the close of the Roman Empire. Lastly,