History of Modern Philosophy / From Nicolas of Cusa to the Present Time

by Richard Falckenberg

With this failure to perceive the intuitive element in mathematics was joined the mistake of overlooking its synthetic character. The syllogistic method of presentation employed in the Euclidean geometry led to the belief that the more special theorems had been derived from the simpler ones, and these from the axioms, by a process of conceptual analysis; while the fact is that in mathematics all progress is by intuition alone, the syllogism serving merely to formulate and explain truths already attained, but not to supply new ones. Following the example of mathematics thus misunderstood, the mission of philosophy was made to consist in the development of the truths slumbering in pregnant first principles by means of logical analysis. If only there were metaphysical axioms! If we only did not demand, and were not compelled to demand, of true science that it increase our knowledge, and not merely give an analytical explanation of knowledge. When once the clearness and distinctness of conceptions had been taken in so purely formal a sense, it was inevitable that in the end, as productivity became less, the principle should be weakened down to a mere demand for the explanation and elucidation of the metaphysical ideas present in popular consciousness. Thus the rationalistic current lost itself in the shallow waters of the Illumination, which soon gave as ready a welcome to the empirical theories—since these also were able to legitimate themselves by clear and distinct conceptions—as it had given to the results of the rationalistic systems.

It was thus easy to see that each of the contending parties had been guilty of one-sidedness, and that in order to escape this a certain mean must be assumed between the two extremes; but it was a much more difficult matter to discover the due middle ground. Neither of the opposing standpoints is so correct as its defenders believe, and neither so false as its opponents maintain. Where, then, on either side, does the mistaken narrowness begin, and how far does the justification of each extend?

The conflict centers, first, about the question concerning the origin of human knowledge and the sphere of its validity. Rationalism is justified when it asserts that some ideas do not come from the senses. If knowledge is to be possible, some concepts cannot originate in perception, those, namely, by which knowledge is constituted, for if they should, it would lack universality and necessity. The sole organ of universally valid knowledge is reason. Empiricism, on the other hand, is justified when it asserts that the experiential alone is knowable. Whatever is to be knowable must be given as a real in sensuous intuition. The only organ of reality is sensibility. Rationalism judges correctly concerning the origin of the most important classes of ideas; empiricism concerning the sphere of their validity. The two may be thus combined: some concepts (those which produce knowledge) take their origin in reason or are a priori, but they are valid for objects of experience alone. The conflict concerns, secondly, the use of the deductive (syllogistic) or the inductive method. Empiricism, through its founder Bacon, had recommended induction in place of the barren syllogistic method, as the only method which would lead to new discoveries. It demands, above all things, the extension of knowledge. Rationalism, on the contrary, held fast to the deductive method, because the syllogism alone, in its view, furnishes knowledge valid for all rational beings. It demands, first of all, universality and necessity in knowledge. Induction has the advantage of increasing knowledge, but it leads only to empirical and comparative, not to strict universality. The syllogism has the advantage of yielding universal and necessary truth, but it can only explicate and establish knowledge, not increase it. May it not be possible so to do justice to the demands of both that the advantages which they seek shall be combined, and the disadvantages which have been feared, avoided? Are there not cognitions which increase our knowledge (are synthetic) without being empirical, which are universally and necessarily valid (a priori) without being analytic? From these considerations arises the main question of the Critique of Pure Reason: How are synthetic judgments a priori possible?

The philosophy of experience had overestimated sense and underestimated the understanding, when it found the source of all knowledge in the faculty of perception and degraded the faculty of thought to an almost wholly inactive recipient of messages coming to it from without. From the standpoint of empiricism concepts (Ideas) deserve confidence only in so far as they can legitimate themselves by their origin in sensations (impressions). It overlooks the active character of all knowing. Among the rationalists, on the other hand, we find an underestimation of the senses and an overestimation of the understanding. They believe that sense reveals only the deceptive exterior of things, while reason gives their true non-sensuous essence. That which the mind perceives of things is deceptive, but that which it thinks concerning them is true. The former power is the faculty of confused, the latter the faculty of distinct knowledge. Sense is the enemy rather than the servant of true knowledge, which consists in the development and explication of pregnant innate conceptions and principles. These philosophers forget that we can never reach reality by conceptual analysis; and that the senses have a far greater importance for knowledge than merely to give it an impulse; that it is they which supply the understanding with real objects, and so with the content of knowledge. Beside the (formal) activity (of the understanding), cognition implies a passive factor, a reception of impressions. Neither sense alone nor the understanding alone produces knowledge, but both cognitive powers are necessary, the active and the passive, the conceptual and the intuitive. Here the question arises, How do concept and intuition, sensuous and rational knowledge, differ, and what is the basis of their congruence? Notwithstanding their different points of departure and their variant results, the two main tendencies of modern philosophy agree in certain points. If the conflict between the two schools and their one-sidedness suggested the idea of supplementing the conclusions of the one by those of the other, the recognition of the incorrectness of their common convictions furnished the occasion to go beyond them and to establish a new, a higher point of view above them both, as also above the eclecticism which sought to unite the opposing principles. The errors common to both concern, in the first place, the nature of judgment and the difference between sensibility and understanding. Neither side had recognized that the peculiar character of judgment consists in active connection. The rationalists made judgment an active function, it is true, but a mere activity of conscious development, of elucidation and analytical inference, which does not advance knowledge a single step. The empiricists described it as a process of comparison and discrimination, as the mere perception and recognition of the relations and connections already existing between ideas; while in reality judgment does not discover the relations and connections of representations, but itself establishes them. In the former case the synthetic moment is ignored, in the latter the active moment. The imperfect view of judgment was one of the reasons for the appearance of extreme theories concerning the origin of ideas in reason or in perception. Rationalism regards even those concepts which have a content as innate, whereas it is only formal concepts which are so. Empiricism regards all, even the highest formal concepts (the categories), as abstracted from experience, whereas experience furnishes only the content of knowledge, and not the synthesis which is necessary to it. On the one hand too much, and on the other too little, is regarded as the original possession of the understanding. The question "What concepts are innate?" can be decided only by answering the further question, What are the concepts through which the faculty of judgment connects the representations obtained from experience? These connective concepts, these formal instruments of synthesis are a priori. The agreement of the two schools is still greater in regard to the relation of sense and understanding, notwithstanding the apparently sharp contrast between them. The empiricist considers thought transformed, sublimated perception, while the rationalist sees in perception only confused and less distinct thought. For the former concepts are faded images of sensations, for the latter sensations are concepts which have not yet become clear; the difference is scarcely greater than if the one should call ice frozen water, and the other should prefer to call water melted ice. Both arrange intuition and thought in a single series, and derive the one from the other by enhancement or attenuation. Both make the mistake of recognizing only a difference in degree where a difference in kind exists. In such a case only an energetic dualism can afford help. Sense and understanding are not one and the same cognitive power at different stages, but two heterogeneous faculties. Sensation and thought are not different in degree, but in kind. As Descartes began with the metaphysical dualism of extension and thought, so Kant begins with the noëtical dualism of intuition and thought.

Much more serious, however, than any of the mistakes yet mentioned was a sin of omission of which the two schools were alike guilty, and the recognition and avoidance of which constituted in Kant's own eyes the distinctive character of his philosophy and its principiant-advance beyond preceding systems. The pre-Kantian thinker had proceeded to the discussion of knowledge without raising the question of the possibility of knowledge. He had approached things in the full confidence that the human mind was capable of cognizing them, and with a naïve trust in the power of reason to possess itself of the truth. His trust was naïve and ingenuous, because the idea that it could deceive him had never entered his mind. Now no matter whether this belief in man's capacity for knowledge and in the possibility of knowing things is justifiable or not, and no matter how far it may be justifiable, it was in any case untested; so that when the skeptic approached with his objections the dogmatist was defenseless. All previous philosophy, so far as it had not been skeptical, had been, according to Kant's expression, dogmatic; that is, it had held as an article of faith, and without precedent inquiry, that we possess the power of cognizing objects. It had not asked how this is possible; it had not even asked what knowledge is, what may and must be demanded of it, and by what means our reason is in a position to satisfy such demands. It had left human intelligence and its extent uninvestigated. The skeptic, on the other hand, had been no more thorough. He had doubted and denied man's capacity for knowledge just as uncritically as the dogmatist had believed and presupposed it. He had directed his ingenuity against the theories of dogmatic philosophy, instead of toward the fundamental question of the possibility of knowledge. Human intelligence, which the dogmatist had approached with unreasoned trust and the skeptic with just as unreasoned distrust, is subjected, according to the plan of the critical philosopher, to a searching examination. For this reason Kant termed his standpoint "criticism," and his undertaking a "Critique of Reason." Instead of asserting and denying, he investigates how knowledge arises, of what factors it is composed, and how far it extends. He inquires into the origin and extent of knowledge, into its sources and its limits, into the grounds of its existence and of its legitimacy. The Critique of Reason finds itself confronted by two problems, the second of which cannot be solved until after the solution of the first. The investigation of the sources of knowledge must precede the inquiry into the extent of knowledge. Only after the conditions of knowledge have been established can it be ascertained what objects are attainable by it. Its sphere cannot be determined except from its origin.

Whether the critical philosopher stands nearer to the skeptic or to the dogmatist is rather an idle question. He is specifically distinct from both, in that he summons and guides the reason to self-contemplation, to a methodical examination of its capacity for knowledge. Where the one had blindly trusted and the other suspected and denied, he investigates; they overlook, he raises the question of the possibility of knowledge. The critical problem does not mean, Does a faculty of knowledge exist? but, Of what powers is it composed? are all objects knowable which have been so regarded? Kant does not ask whether, but how and by what means, knowledge is possible. Everyone who gives himself to scientific reflection must postulate that knowledge is possible, and the demand of the noëtical theorists of the day for a philosophy absolutely without assumptions is quite incapable of fulfillment. Nay, in order to be able to begin his inquiry at all, it was necessary for Kant to assume still more special postulates; for that a cognition of cognition is possible, that there is a critical, self-investigating reason could, at first, be only a matter of belief. This would not have excluded a supplementary detailed statement concerning the how of this self-knowledge, concerning the organ of the critical philosophy. But Kant never gave one, and the omission subsequently led to a sharp debate concerning the character and method of the Critique of Reason. On this point, if we may so express it, Kant remained a dogmatist.

Kant felt himself to be the finisher of skepticism; but this was chiefly because he had received the strongest impulse to the development of his critique of knowledge from Hume's inquiries concerning causation. Brought up in the dogmatic rationalism of the Wolffian school, to which he remained true for a considerable period as a teacher and writer (till about 1760), although at the same time he was inquiring with an independent spirit, Kant was gradually won over through the influence of the English philosophy to the side of empirical skepticism. Then—as the result, no doubt, of reading the Nouveaux Essais of Leibnitz, published in 1765—he returned to rationalistic principles, until finally, after a renewal of empirical influences,[1] he took the position crystallized in the Critique of Pure Reason, 1781, which, however, experienced still other, though less considerable, changes in the sequel, just as in itself it shows the traces of previous transformations.

[Footnote 1: Cf. H. Vaihinger's Kommentar zu Kants Kritik der reinen Vernunft, vol. i., 1881, pp. 48-49. This is a work marked by acuteness, great industry, and an objective point of view which merits respect. The second volume, which treats of the Transcendental Aesthetic, appeared in 1892.]

It would be a most interesting task to trace in the writings which belong to Kant's pre-critical period the growth and development of the fundamental critical positions. Here, however, we can only mention in passing the subjects of his reflection and some of the most striking anticipations and beginnings of his epoch-making position. Even his maiden work, Thoughts on the True Estimation of Vis Viva, 1747, betokens the mediating nature of its author. In this it is argued that when men of profound and penetrating minds maintain exactly opposite opinions, attention must be chiefly directed to some intermediate principle to a certain degree compatible with the correctness of both parties. The question under discussion was whether the measure of vis viva is equal, as the Cartesians thought, to the product of the mass into the velocity, or, according to the Leibnitzians, to the product of the mass into the square of the velocity. Kant's unsatisfactory solution of the problem—the law of Descartes holds for dead, and that of Leibnitz for living forces—drew upon him the derision of Lessing, who said that he had endeavored to estimate living forces without having tested his own. A similar tendency toward compromise—this time it is a synthesis of Leibnitz and Newton—is seen in his Habilitationsschrift, Principiorum Primorum Cognitionis Metaphysicae Nova Dilucidatio, 1755, and in the dissertation Monadologia Physica, 1756. The former distinguishes between ratio essendi and ratio cognoscendi, rejects the ontological argument, and defends determinism against Crusius on Leibnitzian grounds. In the Physical Monadology Kant gives his adherence to dynamism (matter the product of attraction and repulsion), and makes the monads or elements of body fill space without prejudice to their simplicity. A series of treatises is devoted to subjects in natural science: The Effect of the Tides in retarding the Earth's Rotation; The Obsolescence of the Earth; Fire (Inaugural Dissertation), Earthquakes, and the Theory of the Winds. The most important of these, the General Natural History and Theory of the Heavens, 1755, which for a long time remained unnoticed, and which was dedicated to Frederick II., developed the hypothesis (carried out forty years later by Laplace in ignorance of Kant's work) of the mechanical origin of the universe and of the motion of the planets. It presupposes merely the two forces of matter, attraction and repulsion, and its primitive chaotic condition, a world-mist with elements of different density. It is noticeable that Kant acknowledges the failure of the mechanical theory at two points: it is brought to a halt at the origin of the organic world and at the origin of matter. The mechanical cosmogony is far from denying creation; on the contrary, the proof that this well-ordered and purposive world necessarily arose from the regular action of material forces under law and without divine intervention, can only serve to support our assumption of a Supreme Intelligence as the author of matter and its laws; the belief is necessary, just because nature, even in its chaotic condition, can act only in an orderly and regular way.

The empirical phase of Kant's development is represented by the writings of the 60's. The False Subtlety of the Four Syllogistic Figures, 1762, asserts that the first figure is the only natural one, and that the others are superfluous and need reduction to the first. In the Only Possible Foundation for a Demonstration of the Existence of God, 1763, which, in the seventh Reflection of the Second Division, recapitulates the cosmogony advanced in the Natural History of the Heavens, the discussions concerning being ("existence" is absolute position, not a predicate which increases the sum of the qualities but is posited in a merely relative way), and the conclusion, prophetical of his later point of view, "It is altogether necessary that we should be convinced of the existence of God, but not so necessary that his existence should be demonstrated" are more noteworthy than the argument itself. This runs: All possibility presupposes something actual wherein and whereby all that is conceivable is given as a determination or a consequence. That actuality the destruction of which would destroy all possibility is absolutely necessary. Therefore there exists an absolutely necessary Being as the ultimate real ground of all possibility; this Being is one, simple, unchangeable, eternal, the ens realissimum and a spirit. The Attempt to introduce the Notion of Negative Quantities into Philosophy, 1763, distinguishes—contrary to Crusius—between logical opposition, contradiction or mere negation (a and not-a, pleasure and the absence of pleasure, power and lack of power), and real opposition, which cannot be explained by logic (+a and -a, pleasure and pain, capital and debts, attraction and repulsion; in real opposition both determinations are positive, but in opposite directions). Parallel with this it distinguishes, also, between logical ground and real ground. The prize essay, Inquiry concerning the Clearness (Evidence) of the Principles of Natural Theology and Ethics, 1764, draws a sharp distinction between mathematical and metaphysical knowledge, and warns philosophy against the hurtful imitation of the geometrical method, in place of which it should rather take as an example the method which Newton introduced into natural science. Quantity constitutes the object of mathematics, qualities, the object of philosophy; the former is easy and simple, the latter difficult and complicated—how much more comprehensible the conception of a trillion is than the philosophical idea of freedom, which the philosophers thus far have been unable to make intelligible. In mathematics the general is considered under symbols in concrete, in philosophy, by means of symbols in abstracto; the former constructs its object in sensuous intuition, while the object of the latter is given to it, and that as a confused concept to be decomposed. Mathematics, therefore, may well begin with definitions, since the conception which is to be explained is first brought into being through the definition, while philosophy must begin by seeking her conceptions. In the former the definition is first in order, and in the latter almost always last; in the one case the method is synthetic, in the other it is analytic. It is the function of mathematics to connect and compare clear and certain concepts of quantity in order to draw conclusions from them; the function of philosophy is to analyze concepts given in a confused state, and to make them detailed and definite. Philosophy has also this disadvantage, that it possesses very many undecomposable concepts and undemonstrable propositions, while mathematics has only a few such. "Philosophical truths are like meteors, whose brightness gives no assurance of their permanence. They vanish, but mathematics remains. Metaphysics is without doubt the most difficult of all human sciences (Einsichten), but a metaphysic has never yet been written"; for one cannot be so kind as to "apply the term philosophy to all that is contained in the books which bear this title." In the closing paragraphs, on the ultimate bases of ethics, the stern features of the categorical imperative are already seen, veiled by the English theory of moral sense, while the attractive Observations on the Feeling of the Beautiful and the Sublime, which appeared in the same year, still naïvely follow the empirical road.