It is always hazardous to forecast the estimation in which any man will be held by posterity.  In one sense truly we have no right to anticipate the judgment of the future, sufficient for us to form opinions satisfactory within the limits of our own generation.  Sometimes, by evil chance, a great name is covered with undeserved reproach; and it is reserved for a distant future to do it justice.  But such a work as Mr. Carlyle did for Cromwell we may confidently anticipate will never be required for the name of John Stuart Mill.  He is already enrolled among the first of contemporary thinkers, and from that list his name will never be erased.  The nature of Mr. Mill’s work is such as to make it easy to predict the character of his future reputation.  His is the kind of philosophy that is destined to become the commonplace of the future.  We may anticipate that many of his most remarkable views will become obsolete in the best sense:  they will become worked up into practice, and embodied in institutions.  Indeed, the place that he will hold will probably be closely resembling that of the great father of English philosophy,—­John Locke.  There is indeed, amid distinguishing differences, a remarkable similarity between the two men, and the character of their influence on the world.  What Locke was to the liberal movements of the seventeenth century, Mr. Mill has more than been to the liberal movement of the nineteenth century.  The intellectual powers of the two men had much in common, and they were exercised upon precisely similar subjects.  The “Essay on the Human Understanding” covered doubtless a field more purely psychological than the “Logic;” but we must remember that the “Analysis of the Mind” by the elder Mill had recently carried the inductive study of mind to an advanced point.  If, however, we regard less the topics on which these two illustrious men wrote, than the special service rendered by each of them to intellectual progress, we may not unfittingly compare the work of Locke—­the descent from metaphysics to psychology—­to the noble purpose of redeeming logic from the superstition of the Aristotelians, and exalting it to something higher than a mere verbal exercise for school-boys.  The attack that Locke opened with such tremendous effect on the a priori school of philosophy was never more ably supported than by the “Logic” and controversial writings of Mr. Mill.

The remarkable fact in regard to both these great thinkers—­these conquerors in the realms of abstract speculation—­is their relation to politics.  Locke was the political philosopher of the Revolution of 1688; Mr. Mill has been the political philosopher of the democracy of the nineteenth century.  The vast space that lies between their treatises represents a difference, not in the men, but in the times.  Locke found opposed to the common weal an odious theory of arbitrary and absolute power.  It is interesting to remember what were the giants necessary to be slain