be provisional, tautological, and therefore mislead- ing.
(3) There is another consideration which is said to outweigh all reasoning a priori; Mechanism succeeds. Its explanations, we are told, are clear and precise to a degree unattainable in any other theory, and they satisfy the mind with a sjoithetic view of reality. They alone have delivered us from an intolerable pluralism in the cosmic system, secured that unity of thought which seems to be an imperative need of our mind, and brought under control phenomena which had defied all analysis and which had to be accepted as primary data. Furthermore, the doctrines of Mechanism have enabled us to anticipate observation and to make forecasts which facts in nature have actually confirmed. Herein is a guarantee which, for the Mechanists, is well worth all theoretical proofs.
Such, in the main, is the line of reasoning followed by the adherents of Mechanism. That it is not con- clusive will appear quite clearly from the following examination into its value.
Criticism. — It cannot be denied that mechanistic ideas have played a useful and creditable part in science. Whatever one may think of the Cartesian revolution in the realm o' philosophy, it has certainly stimulated research in the scientific field. This ser- vice cannot be overlooked, even though one be con- vinced of the inability of Mechanism to provide us with a formula of the universe. It is none the less true, however, that Mechanism as a cosmic theory must be rejected.
(1) First of all, there is in the progress of natural phenomena a fundamental fact which Mechanism is unal>le to account for, the irreversibility of cosmic events. All motion is reversiljle: when a moving object has covered the distance from A to B, we at once understand that it can go back over the path from B to A. If, therefore, everj^hing that happens is motion, it is not clear why events in nature should not at times retrace their march, why the fruit should not return to the flower, the flower to the bud, the tree itself to the plant and finally to the seed. True, it is shown that this reversion, even in the mechanistic hypothesis, is exceedingly improbable, but it would not be impossible. Now such reversion, in the case of certain phenomena at least, is more than improbable ; it is inconceivable, for instance, that our limbs should be bruised before the fall which causes the bruise. This irreversibility of cosmic processes is undoubtedly, as the Mechanists themselves admit, the chief diffi- culty against their system.
(2) When we enter within the field of biology, the difficulties against Mechanism multiply. Granted that this doctrine has served as a guide to many suc- cessful investigators, what have they attained in the last analysis? They have not advanced one step nearer to the "formula of life." All the biological facts so far examined and understood have been brought into the category of physico-chemical activi- ties — indeed, this might have been expected; but that is not life. A particular phase is isolated for examina- tion, and the characteristic mark of life is thereljy de- stroyed. For that which characterizes life experimen- tally considered, is the unity, the solidarity of all these particular activities ; all converge to one common pur- pose, the constitution of the living being in its undeni- able individuality. Its explanation surely cannot be found in disintegrating it by analysis. The conflict with Mechanism has now been carried into the experi- mental field, and the last few years have yielded an ever increasing number of observations which seem to defy all mechanistic reduction. These are chiefly con- cerned with almonnal conditions which are brought about during the first stages of individual develop- ment. Sea urchin embryos, taken when they have progressed far enough to permit the determination of the normal growth of each part, and divided into two
or three segments, produce as many animals as there were artificial segments. Must not the conclusion be that there exists in each embryo a simple principle — - an entclechy as Dnesch says, using Aristotle's term — ■ which is one in the whole organism and is entire within each part? Is not this the very contrary of Mechan- ism which claims to reduce everything to the move- ments (interwoven of course, but really independent) of the parts? It is not surprising, therefore, that the adherents of neo-Vitalism should now be numerous, and that their ranks are growing fast.
('A) But it is principally before logical and philo- sophical criticism, that Mechanism seems to give way completely. Those very ideas on the nature of ex- planation, according to which it is attempted to re- duce all reality to terms of the supposed primary no- tions of mass and motion, preclude Mechanism from ever attaining the whole of reahty. The present must be reduced to the past, the new to that which is al- ready known, the complex to the more simple; but this original datum remains, that the complex and the simple are not identical, that the new fact is not the fact which was already known. If we suppose all that was contained in the complex to have been reduced by analysis to simple elements already known, we have still to explain their combination, their unity in the complex; and it is just these that have been destroyed by the explanatory analysis. Given that there is something to explain, something unknown, it is clear that there is something beyond the known and the old, and there must inevitably be some principle which moulds into unity the numerous elements, and which either for the species or for the individual, may in a very broad sense be called the "form". Explana- tions based on analysis do not discover the form, be- cause they begin by destroying it. It may be said, in a particular but entirely acceptable sense, that "form" explains nothing, because to explain is to re- duce, and form is by its very nature irreducible. But from this to the denial of form is a very far cry. The scholastics of the decadent period erred in regarding forms as explanatory principles, but Mechanism dis- torts the reality by reducing it to its "matter", by ignoring its specific and its individual unity. For the same reason, the mechanical interpretations of the dynamic aspect of things, that is to say of cosmic evo- lution, prove futile. It is of course instructive in the highest degree to know what previous state of the uni- verse accounts for the pre.sent state of things; but to look on those anterior efficient causes of things as the adequate representations of their effects, is to lose sight of the fact that these latter are effects, while the former were causes; the consequence is an absolute "statism" and a denial of all causality.
Similar observations might be made on the subject of final causes. The meaning itself of the word final- ity has undergone singular changes since Aristotle and the thirteenth century. Let it suffice to note that finality has its basis in the intellectual nature of an efficient cause, or in the internal tendency of a form viewed from the standpoint of activity, of dynamism. The decadent Scholastics weakened their position when they relied on forms and ends only as means of scientific explanations strictly so called, while Mech- anists are clearly in error when they seek in these same scientific explanations for an account of reality to the exclusion of forms and ends. More might be said of the manifest inader|uacy of quantitative images, of cosmologieal Mathiiiiatism which reduces all continu- ity to discont iuuit >• and all time to coincidences without duration, and of the anti-mechanistic reaction which asserts itself under the name of Energism, and with which the researches of Ostwald and of Duhem arc as- sociated. But these are complex and general prob- lems. We may now resume and draw our conclusions.
Conclusion. — Mechanism, is a cosmological theory which holds that all phenomena in nature are reduci-