We have now got hold of a valid distinction between mechanical and directive agencies. We can distinguish them not by their nature but in relation to the particular phenomenon we are considering. We call them mechanical where that phenomenon is a by-product of the agency, and directive where, if the agency were conscious, we should say that this was its main intent. I can see no more fundamental distinction. It follows from this that the same action can be at once both mechanical (physico-chemical) and directive. The old distinction between vital and mechanical energy disappears. The question resolves itself simply into that of the number of distinct agencies which are deemed necessary to account for the universe.
Now the true way of dealing with this problem of the unity or multiplicity of agencies in nature is, I would suggest, to assume the existence of a single power which is of course psychic and directive but which can only be communicated to matter by degrees and under certain conditions still very obscure. These conditions it itself both creates and uses. Its development in Time and that of matter go on, as it were, on parallel paths, eternally apart (to our limited view) yet eternally inseparable. The key to the course of its development in nature lies in the word Synthesis.[115] Here we seem to have the explanation of the apparent difference between the so-called ‘vital’ and the physico-chemical forces. When matter has been so grouped as to form not a mere aggregate of particles but a synthesis, then that synthesis is enabled to make use of energy in a manner not open to its parts. Synthesis is a condition of the discovery of liberation of unsuspected forces. Thus a synthesis of molecules produces the stage for Life, a synthesis of living particles produces the Cell, a synthesis of cells produces an organism, a synthesis of organisms is a species—for the evidence (most notably that derived from the consideration of bee and ant communities) seems to show that material discontinuity in the members does not preclude the existence of a true synthetic union.[116] The characteristic power gained by a species is that of evolutionary development working in the obscure region of germinal combination and variation. Of course, I am aware that all this is merely a way of representing facts so as to make them intelligible to and manageable by the mind. If any one should object that we do not know what kind of grouping a synthesis is, except precisely through that very organic activity which I have described as its product or accompaniment, I entirely agree. All these terms are intellectual forms—like atoms, molecules, and other concepts of physics. They do not reveal anything; they merely help us to comprehend. In the region of the controversy of Vitalism _versus_ Mechanism, the conceptions which I have been trying to explain enable us, without introducing a multiplicity of different energies, to understand how an organism synthetized by life may exhibit directive action which looks entirely different from any action possible in dead matter. Yet it works under laws of its own, and no doubt the particles of such an organism, if they were conscious, would be unaware that any but physico-chemical processes were in operation; in fact, I should have no hesitation in agreeing with the statement with which the great physiologist, Verworn, concludes an exhaustive analysis of this obscure subject: “The general fact must be regarded as established, that all the work of the organism is based finally upon chemical energy.”[117] But what directs the chemical energy? Something which is not itself a chemical energy and which is associated with the organic synthesis which that energy serves to maintain. Verworn’s statement, it must be borne in mind, is as true of the composition of the Iliad as it is of the digestive process of an animalcule.