III.
In proportion as the several orders of phenomena are conceived as governed by invariable laws, the belief in final causes becomes weaker and tends to disappear. The final causes are imagined by the mind to explain certain combinations of natural phenomena. When the laws of these phenomena are known, this explanation becomes useless, it ceases to have currency. It shares the fate of the whole of theological and metaphysical philosophy, of which it is a part.
The doctrine of final causes is generally regarded as a constituent principle of religious systems. A special argument in favour of the existence of God has even been drawn from it. Comte remarks that it is more probably a consequence of these systems. So long as man believes in the continual action of the gods, or of God, in nature, he does not need the consideration of final causes upon which to found his belief. He does not even dream of it. Later on only, when the religious conception of the world has become weaker, when God has so far withdrawn from the world as to be no longer anything but a sovereign who reigns, but does not govern, then the need is felt to demonstrate His existence, and the order of nature becomes an argument. The consideration of final causes from this point of view is a symptom of the weakening of the theological spirit; it is thus pre-eminently a metaphysical doctrine.
Whatever may be the case, experience witnesses against it. Positive science does not lay down that the world must be conceived as the work of an all-powerful intelligence. For instance, the scientific knowledge of our solar system has shown in the most obvious manner, and in various ways, that the elements of this system were certainly not disposed in the most advantageous manner, and that science allowed us to conceive of a better arrangement.[55] Astronomers may admire a natural finality in the organisation of animals; but the anatomists who know all its imperfections, fall back upon the arrangements of the stars. In what concerns animals, a blind admiration wonders even at evidently detrimental complications: it is the case with the eye, with the bladder, etc.[56] But “it is an almost universal disposition of physiologists to draw, even from their ignorance, as many motives for the admiration of the profound wisdom of a mechanism which they declare they cannot understand.”
In truth, the natural order, so much extolled, is extremely imperfect, and we can without difficulty conceive a better one. The human works, says Comte, from the most simple mechanical appliances to the most sublime political constructions, are generally far superior either in expediency, or in simplicity, to everything that the most perfect natural economy can offer us.[57] Our geometers and our physicians “sufficiently prepared” would do far better than nature, if they dared “to take the direct conception of a new animal mechanism as the object of an intellectual exercise.” This idea of artificial organisms pleases Comte and he often returns to it. He considers that fictions of this kind may be useful in biology to intercalate intermediaries between the several known organisms, in such a manner as to facilitate comparison in making the biological series more homogeneous and continuous.[58] In fact this is what Broca attempted to do, when he endeavoured to connect man with the other primates by hypothetical anthropoids. Quite recently M. Delage has made use of a similar fiction in his Traité de Zoologie.
Comte seldom misses an opportunity of smiling at the stupid admiration of those who believe that nature has done everything “for the best,” or that everything in it has been ordered by a providential wisdom. But we can surprise him also in the very act of admiration; not doubtless on the subject of astronomical or biological phenomena, but in the chapter which lies nearest to his heart, that of social facts. He writes, “we cannot experience too much respect and admiration when we see this universal natural disposition which is the primary basis of all society....”[59] and elsewhere: “Can one really conceive, in the whole of natural phenomena, a more marvellous spectacle than this regular and continuous convergence of an immensity of individuals....”[60]
However, there is not here a contradiction. In reality, although Comte says that the consideration of final causes must be accepted altogether, or rejected altogether, he does not himself reject it as entirely as he seems at first to do.
What he formally rejects, is the finality understood in the theological or metaphysical manner: Cœli enarrant gloriam Dei. He does not admit that we can “explain” the natural order by a supernatural wisdom. But he in no way contests the finality which Kant called internal. This finality, or better, this reciprocal causality appears in living beings, where the whole and the parts are reciprocally end and means. The tree could not subsist without the leaves any more than the leaves without the tree. Comte expresses this idea in terms which are almost identical with those of Kant, although he did not know them. “We shall,” he says, “cease defining a living being by the collection of its organs, as if these could exist isolated.... In biology the general notion of the being, always precedes that of any of its parts whatever. In sociology, where partial interdependence is less intimate although wider, it would be a serious heresy to define humanity by man ... a fortiori in biology we ought not to conceive the whole from its parts.”[61] As soon as we rise above the inorganic world, the first condition for the study of phenomena is the idea of their consensus, first in biology, and then in sociology. This consensus corresponds to Kant’s internal finality.
But the distinction between internal finality and external finality cannot be strictly maintained. We will never affirm that some beings were made in view of others. This would be in the highest degree a theological “explanation” of the first order. But from the positive point of view, we observe that, in order to subsist, organisms need not only special intimate structure, but further require a certain equilibrium of external conditions. At each moment their existence depends at once on their constitution and on the “milieu.” This word, which was destined to attain such popularity and the theory of the “milieu” which Taine has rendered no less popular, belong to Comte. Undoubtedly, the idea was suggested to him, on the one hand by Montesquieu and by his successors, and on the other by the labours of Lamarck and of the contemporary biologists. He also drew inspiration from Bichat’s celebrated Recherches sur la vie et la mort. But Bichat especially insisted upon the antagonism between the living being and the forces of the inorganic world which press upon him from all sides. Comte thinks, on the contrary, that the very existence of living beings is the proof of a sufficient harmony between their organism and the milieu. And what we cannot dispute is his merit in having generalised the idea specially applied by Montesquieu to social facts, and also specially applied by Lamarck and Bichat to the phenomena of life.
“I designate by this word “milieu,” says Comte, in excusing himself for the new meaning which he gives it, “not only the fluid in which the organism is immersed, but, in general, the totality of external circumstances of any kind whatever necessary to the existence of each determined organism.”[62]
Properly speaking then, Comte does not reject the doctrine of final causes; he only transforms it. He had declared this himself in his opuscule in 1822. “The doctrine of final causes has been converted by the physiologists into the principle of the conditions of existence.” Positive philosophy appropriates, “with the understanding of a suitable change,” the general ideas primitively invented by the theological and metaphysical philosophies. As the positive notion of the mathematical laws of phenomena arose out of the metaphysical conceptions of the Pythagoricians concerning the properties of numbers, so the scientific principle of the conditions of existence springs from the hypothesis of final causes.[63]
An example will allow us to realise this transformation in the act.
The stability of the solar system renders the existence of living species on the earth possible. A good example of finality it would seem. Nevertheless this stability is simply a necessary consequence, according to the mechanical laws of the world, of some circumstances characteristic of our system: extreme smallness of the planetary masses in comparison to the central mass, small eccentricity of their orbits, slight mutual inclination of their planes, etc. Since, in fact, we exist it must be that the system of which we form a part is arranged so as to allow of this existence.” The so-called final cause would then reduce itself here, as on all analogous occasions, to this childish remark: the only stars inhabited are those which are habitable. In a word, we return to the principle of the conditions of existence, which is the true positive transformation of the doctrine of final causes, and whose bearings and fertility are far superior.”[64]
In order to give the formula of this principle, we must have recourse to the general distinction established by de Blainville between the static point of view and the dynamic point of view.
Every active being, and in particular every living being, can be analysed from these two points of view. The static analysis considers its elements in their relations of simultaneous connexions. The dynamic analysis discovers the laws of their joint evolution. The first is the share of the anatomist, the second that of the physiologist. Now it is clear that these two analyses are complementary to one another, and are even separately unintelligible. For instance, the anatomist is constantly guided by physiological considerations. Conversely, without anatomical knowledge there is no positive physiology.
Thus, the statical analysis establishes the laws of coexistence, the dynamic analysis the laws of succession or of movement. The principle of the conditions of existence is nothing else than the direct and general conception of the necessary harmony of these two analyses, that is to say, of the agreement of these two orders of laws.[65] If this harmony, in fact, was not realised, no living being, no natural system of phenomena could subsist. From the point of view of the object this principle accounts for the permanence of beings: from the point of view of the subject it expresses the possibility of science.
Why does Comte say that the importance and fertility of this principle are far superior to those of the doctrine of final causes? It is because this latter doctrine claims to “explain.” In referring the natural order to the wisdom of a Providence, it dispenses in some measure with scientific research, or at least it does not require it. The principle of the conditions of existence, on the contrary, is closely allied to the positive conception of natural phenomena. It only implies the existence of laws. It only establishes the continuity of the relations between these laws, a continuity verified by experience, since beings subsist and reproduce themselves. In a word, it allows us to connect the laws of succession with the laws of coexistence everywhere. Now, to connect is the essential function of science. By means of this principle not only the successive moments of any natural evolution whatever are understood as having solidarity with each other but the whole of this evolution becomes intelligible by its relation to the statical conditions to which it corresponds. And, in virtue of the relativity of science, or, if we prefer it, of the universal reciprocal action of all phenomena, the principle of the conditions of existence leads the human mind to a scientific investigation ever more exact and never completed.
This positive transformation of the doctrine of final causes had already been clearly sketched by the philosophers of the XVIII. century whom Comte knew very well, by Diderot, by Hume, by d’Holbach. Hume says, for instance,[66] “It is useless to insist upon the uses of parts in animals or in plants, and on their curious adaptation one to another. I should much like to know how an animal could subsist without this adaptation. Do we not see that if it ceases he perishes at once, and that the matter of which he was composed takes some other shape?” And d’Holbach, “These wholes would not exist in the form which they bear, if their parts ceased to act as they do; that is to say, ceased to be arranged in such a way as to lend themselves to being mutually helpful to each other. To be surprised that the heart, the brain, the eyes, the arteries, etc., of an animal act as they do; or that a tree produces fruit, is to be surprised that a tree or an animal exists. These beings would not exist or would no longer be what they are, if they ceased to act as they do: this is what happens when they die.”[67]
Comte makes this criticism of the doctrine of final causes his own. But, faithful to his maxim, “We only destroy what we replace,” he claims to substitute a positive principle to this metaphysical doctrine, which preserves the elements in it which are compatible with the scientific method. It is the principle of the conditions of existence. In virtue of this principle, by the very fact that such an organ is part of such a living being, it necessarily co-operates in a determined although perhaps unknown manner, with the totality of the acts which make up its existence: an organ no more exists without a function than a function without an organ. But it in no way follows from this that all the organic functions are performed as perfectly as we could imagine them to be. For instance pathological analysis demonstrates that the disturbing action of each organ upon the whole of the economy is very far from being always compensated for by its utility in the normal state. “If, within certain limits, everything is necessarily arranged in such a way as to be able to exist, we should seek in vain, in the majority of effective arrangements, for proofs of a wisdom superior or even equal to human wisdom.”[68]
Extending these considerations to the whole of the phenomena known to us, Comte concludes in almost the same way as Cournot will later on. An order establishes itself in nature, since it subsists, since it is intelligible, since there are laws.[69] Does not the very idea of a law induce at once the corresponding idea of a certain spontaneous order? But “this consequence is not more absolute than the principle from which it is derived.”[70] The experience which reveals this order to us also shows us that it is imperfect, of an imperfection which grows with the complexity of phenomena. Every time that the necessary and sufficient conditions are realised for a natural system to be able to exist, this system exists in fact, however full of imperfections it may be in other respects. “Undoubtedly, an inevitable necessity which links together a series of events, and a premeditated plan which directs them, resemble each other very much so far as the consequences are concerned.”[71] But, if the necessity is established, there is no need to suppose the plan. Now the principle of the conditions of existence, in showing that all that is “indispensable,” is at the same time “inevitable,” renders this supposition superfluous.
A double tendency makes itself felt in this theory. On the one hand Comte, faithful to the spirit of his philosophy, rejects all that claims to go beyond experience, that is to say the transcendental hypothesis of final causes and of optimism. On the other hand, he wishes to account for the order of nature, which is a fact. Now this order, all imperfect as it is, implies not only the existence of laws, but moreover a permanent harmony between these laws. “The present is full of the past, and big with the future.” The principle of the conditions of existence explains this permanence of order, at least as much as it needs to be explained from the positive point of view. For it states that everywhere, in fact, the dynamical laws are in harmony with the statical laws, and that “progress is a development of order.” The principle of the conditions of existence is no more a priori than the principle of laws. Like it it is founded upon an “immense induction.” Like it again, it only acquires its full power when social science is created, and positive philosophy established.
Should we not be tempted to see in this doctrine a kind of projection of an idealism such as that of Leibnitz on the lines of positive thought? Just as Leibnitz makes mechanism rest upon a deeper dynamism, so Comte completes the principle of laws by the principle of the conditions of existence. True, between these two doctrines there lies all the distance which separates the positive from the metaphysical spirit. But none the less both give symmetrical solutions of the same problem which correspond to one another, the one a priori the other a posteriori.