Periodicity is the scientific name for the Harmony of the Spheres.

The two periodic motions which most essentially affect and concern us human beings are necessarily the two periodic motions of the globe which we inhabit—its rotation upon its axis which gives us the alternation of Day and Night, and its revolution round the Sun which gives us the year with its Seasons. To the former of these, animal life seems most directly related; to the latter, the life of the vegetal orders. It is evident that the forms of animal life on the globe are necessarily determined by the periodic law of the Earth's diurnal rotation. This accounts for the alternations of waking and sleeping, working and resting, and so forth. In like manner the more inert vitality of the vegetable kingdom is determined by the periodic law of the Earth's annual revolution. When fanciful speculators seek to imagine what kind of living beings might be encountered on the other planets of our system, they usually make calculations as to the force of gravity on the surface of these planets and conjure up from such data the possible size of the inhabitants, their relative strength and agility of movement, etc. So far so good. But the first question we should ask, before proceeding to our speculative synthesis, should rather be the length of the planet's diurnal rotation and annual revolution periods. Certain planets, such as Mars and Venus, have rotation periods not very different from those of our own Earth.[14:1] Other things being equal, therefore, a certain similarity of animal life must be supposed possible on these planets. On the other hand, the marked difference in their revolution period would lead us to expect a very wide divergence between their lower forms of life, if any such there be, and our own terrestrial vegetation. The shorter the annual period the more would the vegetal approximate to the animal, and vice versa. It would, however, be foolish to waste more time over a speculation so remote.

But these two facts remain unshaken:—(1) That our measurements and whole science of Time depend absolutely on the operation throughout Nature of the Law of Periodicity, and (2) that the periodicities which affect and determine animal and vegetal life upon our Earth are the periodic movements of rotation and revolution of that Earth itself.

Now it is to the curvilinear motions of the heavenly bodies that we must ascribe our subjection to the periodic law. If these heavenly bodies moved for ever in straight lines, as they would do if unacted on by natural forces, the periodic rhythm of Nature would disappear.

It is to the fact that all Nature is under the constraint due to the constant silent operation of physical Force that we owe, therefore, the law which determines the most essential features of vitality. The pulsations in which life consists and by which it is sustained are attributable to the constraint and limitation which we recognise as the effect of the operation of Natural Force. It is to this same cause that we ascribe the resistance of cohering masses in virtue of which sensation arises and by which our experience is punctuated. It is by means of these obstructions to free activity that our experience is denoted, and by reference to these that it is cognised. Indeed, Activity itself as we know it depends upon and presupposes the existence of these cohering masses.

Thus the operation of Natural Force and the constraint and limitation which are thereby imposed upon our activity appear at once to determine the conditions of life and to furnish the fundamental implements of Knowledge.

We cannot overleap the barriers by which Life is constrained. These, whilst, on the one hand they seem to create the environment which sustains Life, on the other hand seem to impose upon it the limitations under which it inevitably fails and dies. We cannot even in imagination conceive, either as reality or as fancy, the illimitable puissance of a Life perfectly free and unrestrained. Yet the assurance that Perfect Love could overcome the bonds of Materiality and Death encourages in mankind the Hope of an existence beyond the impenetrable veil of physical limitation. And this at any rate may be admitted, namely, that that dynamic condition in which materiality arises is also the condition-precedent of Tridimensionality, of Force, of Time, and of Mutation. But we cannot thus account for the elan vital itself.

FOOTNOTES:

II

THE ORIGIN OF PHYSICAL CONCEPTS

"Penser c'est sentir," said Condillac. "It is evident," said Bishop Berkeley, "to one who takes a survey of the objects of Human Knowledge that they are either ideas actually imprinted on the senses or else such as are perceived by attending to the passions and operations of the Mind, or lastly ideas formed by help of memory and imagination either combining, dividing, or barely representing those originally perceived in the foresaid ways." J. S. Mill tells us, "The points, lines, circles, and squares which one has in his mind are, I apprehend, simply copies of points, lines, circles, and squares which he has known in his experience," and again, "The character of necessity ascribed to the truths of Mathematics and even, with some reservations to be hereafter made, the peculiar certainty attributed to them is an illusion." "In the case of the definitions of Geometry there exist no real things exactly conformable to the definitions." Again Taine, "Les images sont les exactes reproductions de la sensation." Again Diderot, "Pour imaginer il faut colorer un fond et détacher de ce fait des points en leur supposant une couleur differente de celle du fond. Restituez à ces points la même couleur qu'au fond,—à l'instant ils se confondent avec lui et la figure disparait," etc. Again, Dr. Ernest Mach, Vienna, remarks, "We are aware of but one species of elements of Consciousness: sensations." "In our perceptions of Space we are dependent on sensations." Dr. Mach repeatedly refers to "space-sensations," and indeed affirms that all sensation is spatial in character.