In the epistemological problem as offered by the Kantian philosophy of cognition there is involved the subordinate but highly important question as to the proper method of philosophy. Is the method of criticism, as that method was employed in the three Critiques of Kant, the exclusive, the sole appropriate and productive way of advancing human philosophical thought? I do not think that the experience of the nineteenth century warrants an affirmative answer to this question of method. This experience has certainly, however, resulted in demonstrating the need of a more thorough, consistent, and fundamental use of the critical method than that in which it was employed by Kant. And this improved use of the critical method has induced a more profound study of the psychology of cognition, and of the historical development of philosophy in the branch of epistemology. More especially, however, it has led to the reinstatement of the value-judgments, as means of cognition, in their right relations of harmony with the judgments of fact and of law.
The second of the greater problems which the critical philosophy of the eighteenth handed on to the nineteenth century is the ontological problem. This problem, even far more than the epistemological, has excited the intensest interest, and called for the profoundest thought, of reflective minds during the last hundred years. This problem engages in the inquiry as to what Reality is; for to define philosophy from the ontological point of view renders it "the rational science of reality;" or, at least, "the science of the supreme and most important realities." In spite of the fact that the period immediately following the conclusion of the Kantian criticism was the age when the people were singing
"Da die Metaphysik vor Kurzem unbeerbt abging,
Werden die Dinge an sich jetzo sub hasta verkauft,"
the cultivation of the ontological problem, and the growth of systematic metaphysics in the nineteenth century, had never previously been surpassed. In spite of, or rather because of, the fact that Kant left the ancient body of metaphysics so dismembered and discredited, and his own ontological structure, in such hopeless confusion, all the several buildings both of Idealism and of Realism either rose quickly or were erected upon the foundations made bare by the critical philosophy.
But especially unsatisfactory to the thought of the first quarter of the nineteenth century was the Kantian position with reference to the problem in which, after all, both the few who cultivate philosophy and the multitude who share in its fruits are always most truly interested; and this is the ethico-religious problem. In the judgment of the generation which followed him, Kant had achieved for those who accepted his points of view, his method of philosophizing, and his results, much greater success in "removing knowledge" than in "finding room for faith." For he seemed to have left the positive truths of Ethics so involved in the negative positions of his critique of knowledge as greatly to endanger them; and to have entangled the conceptions of religion with those of morality in a manner to throw doubt upon them both.
The breach between the human cognitive faculties and the ontological doctrines and conceptions on which morality and religion had been supposed to rest firmly, the elaborately argued distrust and skepticism which had been aimed against the ability of human reason to reach reality, and the consequent danger which threatened the most precious judgments of worth and the ontological value of ethical and æsthetical sentiments, could not remain unnoticed, or fail to promote ceaseless and earnest efforts to heal it. The hitherto accepted solutions of the problems of cognition, of being, and of man's ethico-religious experience, could not survive the critical philosophy. But the solutions which the critical philosophy itself offered could not fail to excite opposition and to stimulate further criticism. Moreover, certain factors in human nature, certain interests in human social life, and certain needs of humanity, not fully recognized and indeed scarcely noticed by criticism, could not fail to revive and to enforce their ancient, perennial, and valid claims.
In a word, Kant left the main problems of philosophy involved in numerous contradictions. The result of his penetrating but excessive analysis was unwarrantably to contrast sense with understanding; to divide reason as constitutive from reason as regulative; to divorce the moral law from our concrete experience of the results of good and bad conduct, true morality from many of the noblest desires and sentiments, and to set in opposition phenomena and noumena, order and freedom, knowledge and faith, science and religion. Now the highest aim of philosophy is reconciliation. What wonder, then, that the beginning of the last century felt the stimulus of the unreconciled condition of the problems of philosophy at the end of the preceding century! The greatest, most stimulating inheritance of the philosophy of the nineteenth century from the philosophy of the eighteenth century was the "post-Kantian problems."
II. The lines of the movement of philosophical thought and the principal contributory influences which belong to the nineteenth century may be roughly divided into two classes; namely, (1) those which tended in the direction of carrying to the utmost extreme the negative and destructive criticism of Kant, and (2) those which, either mainly favoring or mainly antagonizing the conclusions of the Kantian criticism, endeavored to place the positive answer to all three of these great problems of philosophy upon more comprehensive, scientifically defensible, and permanently sure foundations. The one class so far completed the attempt to remove the knowledge at which philosophy aims as, by the end of the first half of the century, to have left no rational ground for any kind of faith. The other class had not, even by the end of the second half of the century, as yet agreed upon any one scheme for harmonizing the various theories of knowledge, of reality, and of the ground of morality and religion. There appeared, however,—especially during the last two decades of the century,—certain signs of convergence upon positions, to occupy which is favorable for agreement upon such a scheme, and which now promise a new constructive era for philosophy. The terminus of the destructive movement has been reached in our present-day positivism and philosophical skepticism. For this movement there would appear to be no more beyond in the same direction. The terminus of the other movement can only be somewhat dimly descried. It may perhaps be predicted with a reasonable degree of confidence as some form of ontological Idealism (if we may use such a phrase) that shall be at once more thoroughly grounded in man's total experience, as interpreted by modern science, and also more satisfactory to human ethical, æsthetical, and religious ideals, than any form of systematic philosophy has hitherto been. But to say even this much is perhaps unduly to anticipate.
If we attempt to fathom and estimate the force of the various streams of influence which have shaped the history of the philosophical development of the nineteenth century, I think there can be no doubt that the profoundest and the most powerful is the one influence which must be recognized and reckoned with in all the centuries. This influence is humanity's undying interest in its moral, civil, and religious ideals, and in the civil and religious institutions which give a faithful but temporary expression to these ideals. In the long run, every fragmentary or systematic attempt at the solution of the problem of philosophy must sustain the test of an ability to contribute something of value to the realization of these ideals. The test which the past century has proposed for its own thinkers, and for its various schools of philosophy, is by far the severest which has ever been proposed. For the most part unostentatiously and in large measure silently, the thoughtful few and the comparatively thoughtless multitude have been contributing, either destructively or constructively, to the effort at satisfaction for the rising spiritual life of man. And if in some vague but impressive manner we speak of this thirst for spiritual satisfaction as characteristic of any period of human history, we may say, I believe, that it has been peculiarly characteristic and especially powerful as an influence during the last hundred years. The opinions, sentiments, and ideals which shape the development of the institutions of the church and state, and the freer activities of the same opinions, sentiments, and ideals, have been in this century, as they have been in every century, the principal factors in determining the character of its philosophical development.
But a more definite and visible kind of influence has constantly proceeded from the centres of the higher education. The universities—especially of Germany, next, perhaps of Scotland, but also of England and the United States, and even in less degree of France and Italy—have both fostered and shaped the evolution of critical and reflective thought, and of its product as philosophy. In Germany during the eighteenth century the greater universities had been emancipating themselves from the stricter forms of political and court favoritism and of ecclesiastical protection and control. This emancipation had already operated at the beginning of the nineteenth century, and it continued more and more to operate throughout this century, for participation in that free thought whose spirit is absolutely essential to the flourishing of true philosophy. All the other colleges and universities can scarcely repay the debt which modern philosophy owes to the universities of Germany. The institutions of the higher education which are moulded after this spirit, and which have a generous share of this spirit, have everywhere been schools of thought as well as schools of learning and research. Without the increasing numbers and growing encouragement of such centres for the cultivation of the discipline of critical and reflective thinking, it is difficult to conjecture how much the philosophical development of the nineteenth century would have lost. Libertas docendi and Academische Freiheit—without these philosophy has one of its wings fatally wounded or severely clipped.