The criticism of the notion of cause is quite similar to that of the notion of substance. It is a notion necessary to the mind, for just as without substance there can be no mental connection between simultaneous phenomena, in the same way without cause there can be no connection between successive phenomena. Causality is the necessary law that connects each phenomenon with its anterior conditions. Without this law there could be no science, no induction, no experience. It cannot, consequently, be derived from experience, since it is the very condition of it. But do we seek to render cause objective as well as substance? If so, we must understand it in a different sense. Cause is no longer merely a phenomenon anterior to another, the antecedent of a consequent. It is something quite different, it is force, the active power, that initiates the movement, and of which we find the type in our own consciousness. Hence, to render cause objective is nothing less than to spiritualize the universe, to suppose everywhere causes similar to ours—it is a kind of universal Fetichism. And, further, we fall into the same difficulties as we did with regard to substance. Is there only one cause or many causes? Lastly, causation thus understood is of no use whatever to science, for science has no need at all of metaphysical forces, that which is necessary to science, and employed by it under the name of force, being a measurable quantity which it disengages from phenomena and from experience.
On this new ground the difficulty that confronts critical idealism is the same as that affecting the notion of substance. It lies in defending the position against empiricism, from which are borrowed all the arguments against the reality of the cause, while attempting, nevertheless, to preserve the notion of it. How succeed in retaining as an à priori law what empiricism declares to be only an acquired habit? How explain a law of mind imposing a determined order on external phenomena? How can the entirely subjective need of relation determine phenomena to produce themselves in the order desired by our intelligence? The thunder rolls: my mind, in virtue of an innate law, insists on this phenomenon being connected with a certain totality of antecedent phenomena—namely, heat, the formation of clouds charged with electricity of different kinds, the meeting of these clouds, and the combination of the two electricities, &c. How and why have these phenomena produced themselves in order to satisfy my mind? Our author somewhere reproaches the partisans of innate ideas with supposing ideas on one side and phenomena on the other. How can he exonerate Kant’s system from this objection? No philosopher ever insisted more than he on the opposition between matter and form, the former being, as he says, “given à posteriori,” the latter ready prepared à priori in the mind. No philosopher, not even Leibnitz, has more radically separated sensibility which is passive from the understanding whose principle is spontaneity. How do these two opposite principles happen to agree? Even were it pointed out that our senses themselves are innate, since our sensations are but the manifestation of the specific activity of each one of them—light, of the optic nerve, sound, of the acoustic—it still remains certain that our sensations are only subjective as regards their content and not as regards their origin; they arise in virtue of causes to us unknown. How should understanding, by aid of a purely mental law, and in order to its own satisfaction, evoke sensible phenomena from nothingness, and if it had such a power, it could only be in virtue of an active force, that is, of a veritable causality? You say that you require relation, without which there could be no knowledge. And why must there be knowledge because you feel the need of it? And why should there not be in the understanding a need of unity and relation that sensibility does not satisfy? To say that the mind at the same time that it thinks the law produces phenomena conformable to that law, is to make the mind itself the cause in the objective and metaphysical sense of the word—is no other than that universal spiritualism that the author began by refuting. We are therefore very far from admitting his criticism of the principles of causality. Let us go on to the notion of the absolute.
M. Liard begins very properly by pointing out the confusion too often made between the notion of the infinite and that of the absolute. He says that the infinite can only be strictly understood in the mathematical sense, but that hence, as Leibnitz has said, the true infinite is the absolute. He admits the existence in the mind of the notion of the absolute in so far as it is inseparable from that of the relative. The Scotch philosopher, Hamilton, had endeavoured to suppress this notion, and had reproached Kant for not having completely exorcised the phantom of the absolute,[2] and for having retained it in the character of idea while contesting its objective existence. It is remarkable that on this point, so decisive for metaphysics, Hamilton should have been opposed and refuted by the more modern English philosophers, who often pass for having pushed the critical and negative spirit further than he, when, indeed, on this point it is just the contrary. Herbert Spencer especially is one whom it is interesting to consult here. He maintains against Hamilton the notion of the absolute as positive, not negative, “as the correlative notion of the relative, as the substratum of all thoughts”—I quote verbally—“as the most important element of our knowledge.”[3] He also maintains in opposition to Hamilton that the affirmation of the absolute is “a knowledge and not a belief.” Only according to him this object that underlies all our thoughts is absolutely indeterminable by us. We know that it is, not what it is. It is the incomprehensible, the unknowable.
M. Liard seems to us substantially to admit all these conclusions. “Existence by others,” he says, “is not to be understood without self-existence.” “Without the spur of the notion of the absolute, how comprehend the obstinate persistence of the human mind in transcending the limits of the relative? Is not this a proof that the relative is not sufficient to itself?” It is one thing to affirm the absolute, another to determine its nature. Even granting that we be powerless to speak as to the essence of the absolute, and that it can never be for us other than the indeterminable and unknowable, “is it nothing to be assured of the existence of an unknowable? At all events religious beliefs might in default of scientific certainty find in an irremovable basis this conviction.”
We see therefore that our author agrees with Mr. Herbert Spencer in granting the existence of the absolute; he does not seem to reduce it, as Kant does, to a mere idea. He confines himself to saying that it cannot be determined. He shows that none of the notions that have been previously examined can fill up the concept of the absolute. Neither space, nor time, nor substance, nor cause, nor the totality of phenomena, can be raised to the notion of absolute. It is therefore indeterminable. Now, as the absolute is the proper object of metaphysics, it follows that metaphysics lack an object, having nothing to say thereon. Hence it is self-condemned, and consequently metaphysics is not a science.
Such is the conclusion of the second part. The first appeared to raise us above phenomena by establishing the necessity of thought and of its fundamental law. But the second confines us within the domains of thought, and forbids us to go beyond. There is, indeed, a science of thought, but this science is criticism, not metaphysics. Have we, then, only escaped from positivism to fall into the abyss of scepticism?
Before explaining in what manner the author has endeavoured to escape from this abyss, there is room for an important remark on the previous discussion as to the notion of the absolute. Scepticism on this point may assume three forms. Either, first, we do not even possess the notion of it, our notion is entirely negative,—the absolute is the non-relative, is indeed the relative with a negation: such is the view of Sir W. Hamilton. Or else, secondly, we have the notion of the absolute, of being in itself and by itself, of the superlatively real being, ens realissimum, as Kant expresses it, but it is only a notion, we cannot affirm the existence: this is Kant’s doctrine. Or, thirdly, we have indeed a positive notion of the absolute, and we necessarily affirm its existence, only we are unable to determine its nature: this is the conclusion arrived at by Herbert Spencer. Now, of these three doctrines the two first alone, in our opinion, belong to what may be called criticism. The third is manifestly a return to dogmatism. The more or less of determination in the notion of the absolute is only the second problem of metaphysic; the first is the existence of that absolute. And, moreover, the doctrine of the divine incomprehensibility has always been maintained by the greatest metaphysicians as well as the greatest theologians. All mystics incline to it. There may therefore be room for debate as to the more or less approximative character of our concepts of the absolute. That any of these are adequate, or absolutely adequate, is what no philosopher has ever thought himself obliged to maintain. No doubt, to define the absolute as the unknowable, is to express the doctrine under a very rigorous form, but one could hardly refuse to allow the absolute to be the incomprehensible.
Consequently, then, if the author, as appears to be the case from the passages we have quoted, thinks with Mr. Herbert Spencer that the notion of the absolute corresponds to an existence, and if he contents himself with maintaining its indeterminability, we may, if we like, consider this to be a singularly attenuated metaphysic, but we are not entitled to deny that it amounts to a departure from criticism and a return to metaphysic. If, on the other hand, criticism does at least suppose one fundamental datum,—thought, namely, and with the thought the thinking,—we are still forced to grant to Descartes, and consequently to metaphysic, the existence of the thinking subject; and hence that science which our author declares not to be one would be found already in possession of the claim by the single fact of what he has called the criticism of two fundamental postulates: I think, I am—I think the absolute, the absolute is. And is this then nothing?
We are therefore of opinion that M. Liard ought to have concluded the second part of his work as he did the first—that is to say, that he ought to have shown the insufficiency of criticism as he did that of positivism. To our mind, criticism supposes metaphysic, as positivism supposes criticism. Metaphysic contains the reason of criticism, as criticism does that of positivism. Instead, then, of saying that metaphysic is not a science, we should rather call it the culminating point of science. But in place of following this natural order, which is, indeed, only his own method, our author has preferred to prove criticism right in the second part of his book, and metaphysic right in the third, by a sort of saltus, not contained in what goes before. He has chosen to appear nearer to Kant than he really is; has chosen to carry on his own evolution in Kant’s manner, and to rebuild on different bases what he had demolished; but we shall see that this evolution is in reality quite different from that of Kant, and that his justification of criticism is only apparent, or at least if he defends it, this is really only in order subsequently to undermine it.