THE PERSISTENCE OF FORCE.[12]
§ 72. Before taking a first step in the rational interpretation of
Evolution, it is needful to recognize, not only the facts that Matter is
indestructible and Motion continuous, but also the fact that Force
persists. An attempt to assign the _causes_ of Evolution, would
manifestly be absurd, if that agency to which the metamorphosis in
general and in detail is due, could either come into existence or cease
to exist. The succession of phenomena would in such case be altogether
arbitrary; and deductive science impossible.
Here, indeed, the necessity is even more imperative than in the two
preceding cases. For the validity of the proofs given that Matter is
indestructible and Motion continuous, really depends upon the validity
of the proof that Force is persistent. An analysis of the reasoning
demonstrated that in both cases, the _à posteriori_ conclusion involves
the assumption that unchanged quantities of Matter and Motion are proved
by unchanged manifestations of Force; and in the _à priori_ cognition we
found this to be the essential constituent. Hence, that the quantity of
Force remains always the same, is the fundamental cognition in the
absence of which these derivative cognitions must disappear.
* * * * *
§ 73. But now on what grounds do we assert the persistence of Force?
Inductively we can allege no evidence except such as is presented to us
throughout the world of sensible phenomena. No force however, save that
of which we are conscious during our own muscular efforts, is
immediately known to us. All other force is mediately known through the
changes we attribute to it. Since, then, we cannot infer the persistence
of Force from our own sensation of it, which does not persist; we must
infer it, if it is inferred at all, from the continuity of Motion, and
the undiminished ability of Matter to produce certain effects. But to
reason thus is manifestly to reason in a circle. It is absurd to allege
the indestructibility of Matter, because we find experimentally that
under whatever changes of form a given mass of matter exhibits the same
gravitation, and then afterwards to argue that gravitation is constant
because a given mass of matter exhibits always the same quantity of it.
We cannot prove the continuity of Motion by assuming that Force is
persistent, and then prove the persistence of Force by assuming that
Motion is continuous.
The data of both objective and subjective science being involved in this
question touching the nature of our cognition that Force is persistent,
it will be desirable here to examine it more closely. At the risk of
trying the reader’s patience, we must reconsider the reasoning through
which the indestructibility of Matter and the continuity of Motion are
established; that we may see how impossible it is to arrive by parallel
reasoning at the persistence of Force. In all three cases the
question is one of quantity:—does the Matter, or Motion, or Force, ever
diminish in quantity? Quantitative science implies measurement; and
measurement implies a unit of measure. The units of measure from which
all others of any exactness are derived, are units of linear extension.
From these, through the medium of the equal-armed lever or scales, we
derive our equal units of weight, or gravitative force. And it is by
means of these equal units of extension and equal units of weight, that
we make those quantitative comparisons by which the truths of exact
science are reached. Throughout the investigations leading the chemist
to the conclusion that of the carbon which has disappeared during
combustion, no portion has been lost, and that in any compound
afterwards formed by the resulting carbonic acid the whole of the
original carbon is present, what is his repeatedly assigned proof? That
afforded by the scales. In what terms is the verdict of the scales
given? In grains—in units of weight—in units of gravitative force. And
what is the total content of the verdict? That as many units of
gravitative force as the carbon exhibited at first, it exhibits still.
The quantity of matter is asserted to be the same, if the number of
units of force it counter-balances is the same. The validity of the
inference, then, depends entirely upon _the constancy of the units of
force_. If the force with which the portion of metal called a
grain-weight, tends towards the Earth, has varied, the inference that
Matter is indestructible is vicious. Everything turns on the truth of
the assumption that the gravitation of the weights is persistent; and of
this no proof is assigned, or can be assigned. In the reasonings
of the astronomer there is a like implication; from which we may draw
the like conclusion. No problem in celestial physics can be solved
without the assumption of some unit of force. This unit need not be,
like a pound or a ton, one of which we can take direct cognizance. It is
requisite only that the mutual attraction which some two of the bodies
concerned exercise at a given distance, should be taken as one; so that
the other attractions with which the problem deals, may be expressed in
terms of this one. Such unit being assumed, the momenta which the
respective masses will generate in each other in a given time, are
calculated; and compounding these with the momenta they already have,
their places at the end of that time are predicted. The prediction is
verified by observation. From this, either of two inferences may be
drawn. Assuming the masses to be fixed, the motion may be proved to be
undiminished; or assuming the motion to be undiminished, the masses may
be proved to be fixed. But the validity of one or other inference,
depends wholly on the truth of the assumption that the unit of force is
unchanged. Let it be supposed that the gravitation of the two bodies
towards each other at the given distance, has varied, and the
conclusions drawn are no longer true. Nor is it only in their
concrete data that the reasonings of terrestrial and celestial physics
assume the persistence of Force. They equally assume it in the abstract
principle with which they set out; and which they repeat in
justification of every step. The equality of action and reaction is
taken for granted from beginning to end of either argument; and to
assert that action and reaction are equal and opposite, is to assert
that Force is persistent. The allegation really amounts to this, that
there cannot be an isolated force beginning and ending in nothing; but
that any force manifested, implies an equal antecedent force from which
it is derived, and against which it is a reaction. Further, that the
force so originating cannot disappear without result; but must expend
itself in some other manifestation of force, which, in being produced,
becomes its reaction; and so on continually. Clearly then the
persistence of Force is an ultimate truth of which no inductive proof is
possible.
We might indeed be certain, even in the absence of any such analysis as
the foregoing, that there must exist some principle which, as being the
basis of science, cannot be established by science. All reasoned-out
conclusions whatever, must rest on some postulate. As before shown (§
23), we cannot go on merging derivative truths in those wider and wider
truths from which they are derived, without reaching at last a widest
truth which can be merged in no other, or derived from no other. And
whoever contemplates the relation in which it stands to the truths of
science in general, will see that this truth transcending demonstration
is the persistence of Force.
* * * * *
§ 74. But now what is the force of which we predicate persistence? It is
not the force we are immediately conscious of in our own muscular
efforts; for this does not persist. As soon as an outstretched limb is
relaxed, the sense of tension disappears. True, we assert that in the
stone thrown or in the weight lifted, is exhibited the effect of this
muscular tension; and that the force which has ceased to be present in
our consciousness, exists elsewhere. But it does not exist elsewhere
under any form cognizable by us. It was proved (§ 18), that though, on
raising an object from the ground, we are obliged to think of its
downward pull as equal and opposite to our upward pull; and though it is
impossible to represent these pulls as equal without representing them
as like in kind; yet, since their likeness in kind would imply in the
object a sensation of muscular tension, which cannot be ascribed to it,
we are compelled to admit that force as it exists out of our
consciousness, is not force as we know it. Hence the force of which we
assert persistence is that Absolute Force of which we are indefinitely
conscious as the necessary correlate of the force we know. Thus,
by the persistence of Force, we really mean the persistence of some
Power which transcends our knowledge and conception. The manifestations,
as occurring either in ourselves or outside of us, do not persist; but
that which persists is the Unknown Cause of these manifestations. In
other words, asserting the persistence of Force, is but another mode of
asserting an Unconditioned Reality, without beginning or end.
Thus, quite unexpectedly, we come down once more to that ultimate truth
in which, as we saw, Religion and Science coalesce. On examining the
data underlying a rational theory of Evolution, we find them all at last
resolvable into that datum without which consciousness was shown to be
impossible—the continued existence of an Unknowable as the necessary
correlative of the Knowable. Once commenced, the analysis of the truths
taken for granted in scientific inquiries, inevitably brings us down to
this deepest truth, in which Common Sense and Philosophy are reconciled.
The arguments and conclusion contained in this and the foregoing three
chapters, supply, indeed, the complement to the arguments and conclusion
set forth in the preceding part of this work. It was there first shown,
by an examination of our ultimate religious ideas, that knowledge of
Absolute Being is impossible; and the impossibility of knowing Absolute
Being, was also shown by an examination of our ultimate scientific
ideas. In a succeeding chapter a subjective analysis proved, that while,
by the very conditions of thought, we are prevented from knowing
anything beyond relative being; yet that by these very same conditions
of thought, an indefinite consciousness of Absolute Being is
necessitated. And here, by objective analysis, we similarly find that
the axiomatic truths of physical science, unavoidably postulate Absolute
Being as their common basis.
Thus there is even a more profound agreement between Religion and
Science than was before shown. Not only are they wholly at one on the
negative proposition that the Non-relative cannot be known; but they are
wholly at one on the positive proposition that the Non-relative is an
actual existence. Both are obliged by the demonstrated untenability of
their supposed cognitions, to confess that the Ultimate Reality is
incognizable; and yet both are obliged to assert the existence of an
Ultimate Reality. Without this, Religion has no subject-matter; and
without this, Science, subjective and objective, lacks its indispensable
datum. We cannot construct a theory of internal phenomena without
postulating Absolute Being; and unless we postulate Absolute Being, or
being which persists, we cannot construct a theory of external
phenomena.
* * * * *
§ 75. A few words must be added respecting the nature of this
fundamental consciousness. Already it has been looked at from several
points of view; and here it seems needful finally to sum up the results.
In Chapter IV. we saw that the Unknown Power of which neither beginning
nor end can be conceived, is present to us as that unshaped material of
consciousness which is shaped afresh in every thought. Our inability to
conceive its limitation, is thus simply the obverse of our inability to
put an end to the thinking subject while still continuing to think.
In the two foregoing chapters, we contemplated this fundamental
truth under another aspect. The indestructibility of Matter and the
continuity of Motion, we saw to be really corollaries from the
impossibility of establishing in thought a relation between something
and nothing. What we call the establishment of a relation in thought, is
the passage of the substance of consciousness, from one form into
another. To think of something becoming nothing, would involve that this
substance of consciousness having just existed under a given form,
should next assume no form; or should cease to be consciousness. And
thus our inability to conceive Matter and Motion destroyed, is our
inability to suppress consciousness itself. What, in these two
foregoing chapters, was proved true of Matter and Motion, is, _à
fortiori_, true of the Force out of which our conceptions of Matter and
Motion are built. Indeed, as we saw, that which is indestructible in
matter and motion, is the force they present. And, as we here see, the
truth that Force is indestructible, is the obverse of the truth that the
Unknown Cause of the changes going on in consciousness is
indestructible. So that the persistence of consciousness, constitutes at
once our immediate experience of the persistence of Force, and imposes
on us the necessity we are under of asserting its persistence.
* * * * *
§ 76. Thus, in all ways there is forced on us the fact, that here is an
ultimate truth given in our mental constitution. It is not only a datum
of science, but it is a datum which even the assertion of our nescience
involves. Whoever alleges that the inability to conceive a beginning or
end of the Universe, is a _negative_ result of our mental structure,
cannot deny that our consciousness of the Universe as persistent, is a
_positive_ result of our mental structure. And this persistence of the
Universe, is the persistence of that Unknown Cause, Power, or Force,
which is manifested to us through all phenomena.
Such then is the foundation of any possible system of positive
knowledge. Deeper than demonstration—deeper even than definite
cognition—deep as the very nature of mind, is the postulate at which we
have arrived. Its authority transcends all other whatever; for not only
is it given in the constitution of our own consciousness, but it is
impossible to imagine a consciousness so constituted as not to give it.
Thought, involving simply the establishment of relations, may be readily
conceived to go on while yet these relations have not been organized
into the abstracts we call Space and Time; and so there is a conceivable
kind of consciousness which does not contain the truths, commonly called
_à priori_, involved in the organization of these forms of relations.
But thought cannot be conceived to go on without some element between
which its relations may be established; and so there is no conceivable
kind of consciousness which does not imply continued existence as its
datum. Consciousness without this or that particular _form_ is possible;
but consciousness without _contents_ is impossible.
The sole truth which transcends experience by underlying it, is thus the
persistence of Force. This being the basis of experience, must be the
basis of any scientific organization of experiences. To this an ultimate
analysis brings us down; and on this a rational synthesis must build up.
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Footnote 12:
Some two years ago, I expressed to my friend Professor Huxley, my
dissatisfaction with the current expression—“Conservation of Force;”
assigning as reasons, first, that the word “conservation” implies a
conserver and an act of conserving; and, second, that it does not
imply the existence of the force before that particular manifestation
of it with which we commence. In place of “conservation,” Professor
Huxley suggested _persistence_. This entirely meets the first of the
two objections; and though the second may be urged against it, no
other word less faulty in this respect can be found. In the absence of
a word specially coined for the purpose, it seems the best; and as
such I adopt it.