The excesses and failures of idealist theories of knowledge have always given rise in history to the opposite theory of sensualist nominalism, according to which our ideas are simply transformed sensations. Unhappily, sensualism, in laying down this axiom, never explained the nature and still less the cause of that marvellous transformation. "There is nothing in the understanding," said Locke, "that was not previously in the senses." To which Leibniz rightly replied: "Except the understanding itself;" that is to say, the force which from sensation draws knowledge. By suppressing this ideal principle, you remove from science all element of necessity—that is to say, all general worth. With Hume, the sensualist theory, so far from giving an account of knowledge, ended in pure phenomenalism, i.e. once more, in scepticism. It is, in fact, with isolated sensation as with pure idea; you may press it as much as you will, you will never get out of it anything but what it contains—that is to say, contingencies without any connection between each other. Materialism is still more embarrassed to furnish any theory whatever of knowledge, for it does not even succeed in explaining sensation. Between a mechanical movement and a phenomenon of consciousness there is an impassable abyss. One of the most evident marks of the inferiority of the philosophy of French positivism is that it has not even approached this problem of knowledge, and that it has been able to constitute itself without any other than the popular psychology.
2. The Kantian Theory of Knowledge
Thinkers may to-day be divided into two classes: those who date from before Kant, and those who have received the initiation and, so to speak, the philosophical baptism of his critique. These two classes of minds will always have much ado to understand each other. The first are dogmatists or Pyrrhonists. The second no longer comprehend either dogmatism or Pyrrhonism. For them, the point of view has been displaced. Thanks to Kant, we judge both our knowledge and our faculty of knowing; we give an account to ourselves of the conditions in which it performs its functions, of the forms which determine it, and of the limits that it cannot pass. Kant compared, without exaggeration, the revolution which he effected in philosophy to that which the discovery of Copernicus effected in the system of the world. In philosophy also the sun has ceased to move round the earth, and the ancient illusion has been vanquished and dispersed. The idea and the reality no longer coincide; they are disjoined. The intelligible no doubt is real; but it is not certain that all the real is intelligible. Reality appears to us now as surpassing not only our knowledge, but our means of knowing. The religious notion of mystery has entered into consciousness. Man has attained to intellectual humility. Like his body, his mind is a mean between the infinitely great and the infinitely little, between nothing and everything. The deductive philosophy of the unity and necessary and continuous unfolding of an eternal substance, gives place to the philosophy of observation, which will be found to be that of the antinomies whose permanent conflict produces the ascensional progress of the world and of life.
To make Kantism end in scepticism shows a lack of intelligence. His system enables us, on the contrary, to form the scientific theory of science. The truth is to be found neither in dogmatism nor in Pyrrhonism, both of which Pascal combated with equal vigour. In modern science there is a certitude invincible to the subtlest Pyrrhonism; but there is also in it a sense of the limits of our knowing faculty and of the relative character of our most solid constructions which forbids man ever to be puffed up to the point of believing himself to be God. To be in this mean is to be in the truth. The same critique which establishes the validity of human knowledge lays down the limits beyond which it cannot go. We have come to know ourselves better, and that is the mark of all true progress in philosophy. Know thyself is always its first rule and its final fruit.
The Kantian theory of knowledge, while satisfying the mind, at the same time sets forth the essential antinomies whose normal play constitutes the very life of the ego and explains its multiple manifestations.
There are two elements in all knowledge: an à posteriori element which comes from experience, and an à priori element which comes from the thinking subject. The first is the matter of knowledge; the second is the form. Separate, these two elements are unproductive. With the first alone we have but a reality not known; with the second alone we have but a knowing without reality. Their union renders them mutually fruitful by organising the data of experience into the necessary forms of thought. The principle of causation, e.g., is not in things; it is in the mind, and it is the mind which spontaneously connects all phenomena. Science, at bottom, consists in nothing but the causal connection of things. Where the chain breaks, positive knowledge ends. This clear sense of ignorance on points on which we really are ignorant is still a part of science and one of its principal forces, for it proves that it knows itself very well, and also knows the conditions apart from which it no longer exists. But, whether triumphant or held in check, positive science can neither renounce its task and method nor modify their nature. It can only seek to complete, or rather to lengthen, the chain of phenomena. The success of this ever-identical effort, an effort always in the same direction, is what is called its conquests and its progress. It follows that the irresistible tendency of science will be to extend over the whole of the phenomena the ever-tighter network of an invincible necessity. Determinism is its last word.
On the other hand, the ego which knows is an acting ego. Its thought itself, properly speaking, and this display of science, are only one of the forms of its inner activity. It wills, and it must will. If the world acts on it by sensation, it acts incessantly on the world by its volitions. And let it not be said that the will simply represents a mechanical reaction of the ego, exactly equivalent to the action of the external world upon it,—that it is a simple transformation of energy,—for this is not true. Without here raising the question of liberty, it is certain that I do not give back in will simply what I have received under the form of sensation. I deliberate on the motives which urge me to act; I choose between them; I feel myself under obligation; I feel that I should will the good. It is impossible to conceive of moral action without the idea of end. I conceive it, therefore, under a different form from that of mechanical action. Responsibility and obligation are not less the necessary forms of will than logical necessity is the necessary form of thought. But soon there arises in man the most tragical of conflicts. Scientific determinism renders moral activity unintelligible, and moral activity comes into collision with the determinism of science. If mechanical determinism be absolutely true, my will is null; I am simply an automaton. If my responsibility is real, if my personal energy is not an illusion, there is in the world something besides matter, and, for man, there are other than mechanical laws. Thus divided in myself, I ought not to practise what I know, and I cannot do what I ought. I remain floating between a science which is not moral and a morality that I feel to be unscientific. My intellect destroys my will. As the one develops the other dies. The better I know the laws of the world the less reason I have for living and acting. My morality, at each act, gives the lie to my science, and my science, at each affirmation, refutes my morality. Such is the deep malady, the spiritual misery, of the best of our contemporaries. They feel that, with them, vital energy is in inverse proportion to the extent and penetration of thought. It is then that they declare that pessimism, a radical pessimism, is the truth; that existence, will, desire, are the chief evils, and that the supreme effort of science should be to cure us of them by delivering us from all our illusions; after which, in its turn, it will be extinguished itself, like a flame that has consumed the food on which it fed.
Still, the conscious subject is one. You cannot proclaim it vain without at the same time proclaiming the vanity of its ideas as well as of its efforts. The ruin of morality draws after it the ruin of science. Moreover, the conflict of which we speak is different from a theoretical contradiction whose solution may be indefinitely postponed. The conflict is practical; it is of the vital not of the intellectual order. It is an internal dissolution of the being itself, a struggle between its elementary faculties, in which the mind is weakened, droops, and dies.
The solution, therefore, if there be one, can only be a practical one, a solution springing from the will. What is needed is to give the mind confidence in itself. It is necessary to increase the energy of its inner life in order that it may find the strength to believe and to affirm in face of the universe the sovereignty of spirit. This is the same as saying that the solution of the conflict is religion; not an external religion, doubtless, in whose hands the thought and will of man should abdicate—that would in no wise re-establish their inner and living harmony—but an inward religion, an activity of spirit which grasps in itself the supremacy of the universal spirit, and by an act of intimate confidence, an instinctive impulse of the being ready to perish, affirms to itself its own dignity, and makes to spring up out of its own substance the irresistible religion of spirit. Thus the conflict of the theoretic reason and the practical reason eternally engenders religion in the heart of man. Let us show more clearly still this necessary genesis of religion.
In observing, in reasoning, in generalising, I arrive at a certain knowledge of that which surrounds me; this knowledge of external objects forms within me the contents of what I call my knowledge of the world. On the other hand, in acting, in living, in exercising my will, is formed what I call my knowledge of myself. Consciousness of self, and consciousness of the world, condition and determine each other, and cannot exist without each other. But, at the same time, they enter into mortal conflict. The ego desires to master the world, and the world, in the end, devours the ego. Thought triumphs over Nature and contemns it; Nature takes its revenge and swallows up thought in its abyss. The consciousness of self wishes to bring over to itself the knowledge of the world; and this absorbs and devours the consciousness of self. The synthesis and reconciliation can only be found in the consciousness of something superior to self and the world on which both of them absolutely depend. This synthetic and pacificatory consciousness is the consciousness of universal and sovereign Being; it is the sense of the presence of God. To escape from his distress, man has never had any but this means of salvation. The savage has recourse to it, according to his degree of intellectual life, when, under terror of the phenomena of Nature, and of ever-threatening death, he calls to his aid the obscure power of his gods. The philosopher, nourished on speculation, and arrived at the dualistic and divided consciousness of the disciples of Kant, obeys the same instinctive impulse and the same vital necessity when he seeks in the notion of God the conciliation of the conflict which he feels between the ego and the world, between pure reason and the practical reason. He needs a universal Being on whom he feels himself to depend, and on whom he may equally make to depend the whole universe. In uniting himself to Him, he affirms and confirms his own life; he feels God to be active and present, in his thought under the form of logical law, in his will under the form of moral law. He is saved by faith in the interior God, in whom is realised the unity of his being. It is therefore true to say that the human mind cannot believe in itself without believing in God, and that, on the other hand, it cannot believe in God without finding Him within itself.