The believer in the possibility of a science of history is not called upon to hold either the doctrine of predestination or that of freedom of the will. The only positions which at the outset need to be conceded are that when we perform an action we perform it in consequence of some motive or motives; that those motives are the result of some antecedents; and that, therefore, if we were acquainted with the whole of the precedents and with all the laws of their movements we could with unerring certainty predict the whole of their immediate results. History is the modification of man by nature and of nature by man. We shall find a regularity in the variations of virtuous and vicious actions that proves them to be the result of large and general causes which, working upon the aggregate of society, must produce certain consequences without regard to the decision of particular individuals. Man is affected by purely physical agents--climate, food, soil, geographical conditions, and active physical phenomena. In the earliest civilisations nature is more prominent than man, and the imagination is more stimulated than the understanding. In the European civilisations man is the more prominent, and the understanding is more stimulated than the imagination. Hence the advance of European civilisation is characterised by a diminishing influence of physical laws and an increasing influence of mental laws. Clearly, then, of the two classes of laws which regulate the progress of mankind the mental class is more important than the physical. The laws of the human mind will prove to be the ultimate basis of the history of Europe. These are not to be ascertained by the metaphysical method of studying the inquirer's own mind alone, but by the historical method of studying many minds. And this whether the metaphysician belongs to the school which starts by examining the sensations, or to that which starts with the examination of ideas. Dismissing the metaphysical method, therefore, we must turn to the historical, and study mental phenomena as they appear in the actions of mankind at large. Mental progress is twofold, moral and intellectual, the first having relation to our duties, the second to our knowledge. It is a progress not of capacity, but in the circumstances under which capacity comes into play; not of internal power, but of external advantage. Now, whereas moral truths do not change, intellectual truths are constantly changing, from which we may infer that the progress of society is due, not to the moral knowledge, which is stationary, but to the intellectual knowledge, which is constantly advancing.