Essays Towards a Theory of Knowledge | Page 2

world of molecular
changes; yet it is in operation even there. But it is more especially in
the natural motions of those so-called material masses which constitute
our physical environment that Periodicity most eminently prevails.
Indeed it was by astronomers that the operation of this Law was first
definitely recognised and recorded. 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:
[11:1] Plato in the dialogue Timæus tells us