Since the era of the re-birth of learning, each successive century has been generally distinguishable by some marked intellectual development, by some strong movement which has taken deep hold of the minds of men. Thus the Renascimento period was followed by the century of the Reformation, and that again by the inauguration of the era of modern philosophy, while the eighteenth century has been claimed as the _Saeculum Rationalisticum_, the age of rationalism, in which the claims of reason were pushed to the forefront in the domains of religion and politics. Nothing remained after that but an age of physical science, and surely enough has been given us in the nineteenth century which may with equal accuracy be termed the _Saeculum Scientificum_. It cannot be doubted that a sort of mental intoxication has been set up as a result of the extraordinary successes which have rewarded the efforts of scientific investigators. Everything now-a-days is expressed in terms of science and its formulae. Evolution is the keynote to the learning of the age. Thus Mr. Spencer's system of the Synthetic Philosophy is a bold and comprehensive attempt to take up the whole knowable, and express it anew in the language of development. It is emphatically, professedly, the philosophy of evolution, the rigid application of a purely scientific formula to everything capable of philosophical treatment. Now, having discussed the question of ethics and religion, their distinction and their intimate relations; having shown how that religion comes as the crown and glory of the ethical life, the transfiguration of the ethical ideal and the most powerful stimulus towards the realisation in practice of what is conceived as theoretically desirable, it remains for us to complete our treatment of this aspect of the ethical problem and determine the relations existing between morals and science.