I shall not dwell upon Spinoza (1632-1677), who believed it possible to deduce a world _a priori_ with mathematical precision; upon Christian Wolff (1679-1754), who defined philosophy as the knowledge of the causes of what is or comes into being; upon Fichte (1762-1814), who believed that the philosopher, by mere thinking, could lay down the laws of all possible future experience; upon Schelling (1775-1854), who, without knowing anything worth mentioning about natural science, had the courage to develop a system of natural philosophy, and to condemn such investigators as Boyle and Newton; upon Hegel (1770-1831), who undertakes to construct the whole system of reality out of concepts, and who, with his immediate predecessors, brought philosophy for a while into more or less disrepute with men of a scientific turn of mind.

I shall come down quite to our own times, and consider a man whose conception of philosophy has had and still has a good deal of influence, especially with the general public--with those to whom philosophy is a thing to be taken up in moments of leisure, and cannot be the serious pursuit of a life.
"Knowledge of the lowest kind," says Herbert Spencer, "is _un-unified_ knowledge; Science is _partially-unified_ knowledge; Philosophy is _completely-unified_ knowledge." [1] Science, he argues, means merely the family of the Sciences--stands for nothing more than the sum of knowledge formed of their contributions.

Philosophy is the fusion of these contributions into a whole; it is knowledge of the greatest generality.

In harmony with this notion Spencer produced a system of philosophy which includes the following: A volume entitled "First Principles," which undertakes to show what man can and what man cannot know; a treatise on the principles of biology; another on the principles of psychology; still another on the principles of sociology; and finally one on the principles of morality.

To complete the scheme it would have been necessary to give an account of inorganic nature before going on to the phenomena of life, but our philosopher found the task too great and left this out.
Now, Spencer was a man of genius, and one finds in his works many illuminating thoughts.