Of the Idea of Necessary Connexion
(Section
VII of Enquiry Concerning Human Understanding)
David Hume
Full
text: http://www.infidels.org/library/historical/david_hume/human_understanding.html
PART I.
48 THE
great advantage of the mathematical sciences above the moral consists in
this, that the ideas of the former, being sensible, are always clear and
determinate, the smallest distinction between them is immediately
perceptible, and the same terms are still expressive of the same ideas,
without ambiguity or variation. An oval is never mistaken for a circle, nor
an hyperbola for an ellipsis. The isosceles and scalenum are distinguished by
boundaries more exact than vice and virtue, right and wrong. If any term be defined
in geometry, the mind readily, of itself, substitutes, on all occasions, the
definition for the term defined: Or even when no definition is employed, the
object itself may be presented to the senses, and by that means be steadily
and clearly apprehended. But the finer sentiments of the mind, the operations
of the understanding, the various agitations of the passions, though really
in themselves distinct, easily escape us, when surveyed by reflection; nor is
it in our power to recal the original object, as often as we have occasion to
contemplate it. Ambiguity, by this means, is gradually introduced into our
reasonings: Similar objects are readily taken to be the same: And the
conclusion becomes at last very wide of the premises. One may safely, however, affirm, that, if we consider these
sciences in a proper light, their advantages and disadvantages nearly
compensate each other, and reduce both of them to a state of equality. If the
mind, with greater facility, retains the ideas of geometry clear and
determinate, it must carry on a much longer and more intricate chain of
reasoning, and compare ideas much wider of each other, in order to reach the
abstruser truths of that science. And if moral ideas are apt, without extreme
care, to fall into obscurity and confusion, the inferences are always much
shorter in these disquisitions, and the intermediate steps, which lead to the
conclusion, much fewer than in the sciences which treat of quantity and
number. In reality, there is scarcely a proposition in 49. There are no ideas, which occur in metaphysics, more
obscure and uncertain, than those of power, force, energy or necessary
connexion, of which it is every moment necessary for us to treat in all our
disquisitions. We shall, therefore, endeavour, in this section, to fix, if
possible, the precise meaning of these terms, and thereby remove some part of
that obscurity, which is so much complained of in this species of philosophy.
It seems a proposition, which will not admit of much
dispute, that all our ideas are nothing but copies of our impressions, or, in
other words, that it is impossible for us to think of anything, which we have
not antecedently felt, either by our external or internal senses. I have
endeavoured[i]
to explain and prove this proposition, and have expressed my hopes, that, by
a proper application of it, men may reach a greater clearness and precision
in philosophical reasonings, than what they have hitherto been able to
attain. Complex ideas may, perhaps, be well known by definition, which is
nothing but an enumeration of those parts or simple ideas, that compose them.
But when we have pushed up definitions to the most simple ideas, and find
still some ambiguity and obscurity; what resource are we then possessed of?
By what invention can we throw light upon these ideas, and render them
altogether precise and determinate to our intellectual view? Produce the
impressions or original sentiments, from which the ideas are copied. These
impressions are all strong and sensible. They admit not of ambiguity. They
are not only placed in a full light themselves, but may throw light on their
correspondent ideas, which lie in obscurity. And by this means, we may,
perhaps, attain a new microscope or species of optics, by which, in the moral
sciences, the most minute, and most simple ideas may be so enlarged as to
fall readily under our apprehension, and be equally known with the grossest
and most sensible ideas, that can be the object of our enquiry. 50. To be fully acquainted, therefore, with the idea of
power or necessary connexion, let us examine its impression; and in order to
find the impression with greater certainty, let us search for it in all the
sources, from which it may possibly be derived. When we look about us towards external objects, and
consider the operation of causes, we are never able, in a single instance, to
discover any power or necessary connexion; any quality, which binds the
effect to the cause, and renders the one an infallible consequence of the
other. We only find, that the one does actually, in fact, follow the other.
The impulse of one billiard-ball is attended with motion in the second. This
is the whole that appears to the outward senses. The mind feels no sentiment
or inward impression from this succession of objects: Consequently, there is
not, in any single, particular instance of cause and effect, anything which
can suggest the idea of power or necessary connexion. >From the first appearance of an object, we never can
conjecture what effect will result from it. But were the power or energy of
any cause discoverable by the mind, we could foresee the effect, even without
experience; and might, at first, pronounce with certainty concerning it, by
mere dint of thought and reasoning. In reality, there is no part of matter, that does ever, by
its sensible qualities, discover any power or energy, or give us ground to
imagine, that it could produce any thing, or be followed by any other object,
which we could denominate its effect. Solidity, extension, motion; these qualities
are all complete in themselves, and never point out any other event which may
result from them. The scenes of the universe are continually shifting, and
one object follows another in an uninterrupted succession; but the power of
force, which actuates the whole machine, is entirely concealed from us, and
never discovers itself in any of the sensible qualities of body. We know,
that, in fact, heat is a constant attendant of flame; but what is the
connexion between them, we have no room so much as to conjecture or imagine.
It is impossible, therefore, that the idea of power can be derived from the
contemplation of bodies, in single instances of their operation; because no
bodies ever discover any power, which can be the original of this idea.[ii] 51. Since, therefore, external objects as they appear to
the senses, give us no idea of power or necessary connexion, by their
operation in particular instances, let us see, whether this idea be derived
from reflection on the operations of our own minds, and be copied from any
internal impression. It may be said, that we are every moment conscious of internal
power; while we feel, that, by the simple command of our will, we can move
the organs of our body, or direct the faculties of our mind. An act of
volition produces motion in our limbs, or raises a new idea in our
imagination. This influence of the will we know by consciousness. Hence we
acquire the idea of power or energy; and are certain, that we ourselves and
all other intelligent beings are possessed of power. This idea, then, is an
idea of reflection, since it arises from reflecting on the operations of our
own mind, and on the command which is exercised by will, both over the organs
of the body and faculties of the soul. 52. We shall proceed to examine this pretension; and first
with regard to the influence of volition over the organs of the body. This
influence, we may observe, is a fact, which, like all other natural events,
can be known only be experience, and can never be foreseen from any apparent
energy or power in the cause, which connects it with the effect, and renders
the one an infallible consequence of the other. The motion of our body
follows upon the command of our will. Of this we are every moment conscious.
But the means, by which this is effected; the energy, by which the will
performs so extraordinary an operation; of this we are so far from being
immediately conscious, that it must for ever escape our most diligent
enquiry. For first; is there any principle in all nature more
mysterious than the union of soul with body; by which a supposed spiritual
substance acquires such an influence over a material one, that the most
refined thought is able to actuate the grossest matter? Were we empowered, by
a secret wish, to remove mountains, or control the planets in their orbit;
this extensive authority would not be more extraordinary, nor more beyond our
comprehension. But if by consciousness we perceived any power or energy in
the will, we must know this power; we must know its connexion with the
effect; we must know the secret union of soul and body, and the nature of
both these substances; by which the one is able to operate, in so many
instances, upon the other. Secondly, We are not able to move all the organs of the
body with a like authority; though we cannot assign any reason besides
experience, for so remarkable a difference between one and the other. Why has
the will an influence over the tongue and fingers, not over the heart or
liver? This question would never embarrass us, were we conscious of a power
in the former case, not in the latter. We should then perceive, independent of
experience, why the authority of will over the organs of the body is
circumscribed within such particular limits. Being in that case fully
acquainted with the power or force, by which it operates, we should also
know, why its influence reaches precisely to such boundaries, and no farther.
A man, suddenly struck with palsy in the leg or arm, or who
had newly lost those members, frequently endeavours, at first to move them,
and employ them in their usual offices. Here he is as much conscious of power
to command such limbs, as a man in perfect health is conscious of power to
actuate any member which remains in its natural state and condition. But
consciousness never deceives. Consequently, neither in the one case nor in
the other, are we ever conscious of any power. We learn the influence of our
will from experience alone. And experience only teaches us, how one event
constantly follows another; without instructing us in the secret connexion,
which binds them together, and renders them inseparable. Thirdly, We learn from anatomy, that the immediate object
of power in voluntary motion, is not the member itself which is moved, but
certain muscles, and nerves, and animal spirits, and, perhaps, something
still more minute and more unknown, through which the motion is successively
propagated, ere it reach the member itself whose motion is the immediate
object of volition. Can there be a more certain proof, that the power, by
which this whole operation is performed, so far from being directly and fully
known by an inward sentiment or consciousness, is, to the last degree,
mysterious and unintelligible? Here the mind wills a certain event:
Immediately another event, unknown to ourselves, and totally different from
the one intended, is produced: This event produces another, equally unknown:
Till at last, through a long succession, the desired event is produced. But
if the original power were felt, it must be known: Were it known, its effect
also must be known; since all power is relative to its effect. And vice
versa, if the effect be not known, the power cannot be known nor felt. How
indeed can we be conscious of a power to move our limbs, when we have no such
power; but only that to move certain animal spirits, which, though they
produce at last the motion of our limbs, yet operate in such a manner as is
wholly beyond our comprehension? We may, therefore, conclude from the whole, I hope, without
any temerity, though with assurance; that our idea of power is not copied
from any sentiment or consciousness of power within ourselves, when we give
rise to animal motion, or apply our limbs to their proper use and office.
That their motion follows the command of the will is a matter of common
experience, like other natural events: But the power or energy by which this
is effected, like that in other natural events, is unknown and inconceivable.[iii] 53. Shall we then assert, that we are conscious of a power
or energy in our own minds, when, by an act or command of our will, we raise
up a new idea, fix the mind to the contemplation of it, turn it on all sides,
and at last dismiss it for some other idea, when we think that we have
surveyed it with sufficient accuracy? I believe the same arguments will
prove, that even this command of the will gives us no real idea of force or
energy. First, It must be allowed, that, when we know a power, we
know that very circumstance in the cause, by which it is enabled to produce
the effect: For these are supposed to be synonimous. We must, therefore, know
both the cause and effect, and the relation between them. But do we pretend
to be acquainted with the nature of the human soul and the nature of an idea,
or the aptitude of the one to produce the other? This is a real creation; a
production of something out of nothing: Which implies a power so great, that
it may seem, at first sight, beyond the reach of any being, less than
infinite. At least it must be owned, that such a power is not felt, nor
known, nor even conceivable by the mind. We only feel the event, namely, the
existence of an idea, consequent to a command of the will: But the manner, in
which this operation is performed, the power by which it is produced, is
entirely beyond our comprehension. Secondly, The command of the mind over itself is limited,
as well as its command over the body; and these limits are not known by
reason, or any acquaintance with the nature of cause and effect, but only by
experience and observation, as in all other natural events and in the
operation of external objects. Our authority over our sentiments and passions
is much weaker than that over our ideas; and even the latter authority is
circumscribed within very narrow boundaries. Will any one pretend to assign
the ultimate reason of these boundaries, or show why the power is deficient
in one case, not in another. Thirdly, This self-command is very different at different
times. A man in health possesses more of it than one languishing with
sickness. We are more master of our thoughts in the morning than in the
evening: Fasting, than after a full meal. Can we give any reason for these
variations, except experience? Where then is the power, of which we pretend
to be conscious? Is there not here, either in a spiritual or material
substance, or both, some secret mechanism or structure of parts, upon which
the effect depends, and which, being entirely unknown to us, renders the
power or energy of the will equally unknown and incomprehensible? Volition is surely an act of the mind, with which we are
sufficiently acquainted. Reflect upon it. Consider it on all sides. Do you
find anything in it like this creative power, by which it raises from nothing
a new idea, and with a kind of Fiat, imitates the omnipotence of its Maker,
if I may be allowed so to speak, who called forth into existence all the
various scenes of nature? So far from being conscious of this energy in the
will, it requires as certain experience as that of which we are possessed, to
convince us that such extraordinary effects do ever result from a simple act
of volition. 54. The generality of mankind never find any difficulty in
accounting for the more common and familiar operations of nature- such as the
descent of heavy bodies, the growth of plants, the generation of animals, or
the nourishment of bodies by food: But suppose that, in all these cases, they
perceive the very force or energy of the cause, by which it is connected with
its effect, and is for ever infallible in its operation. They acquire, by
long habit, such a turn of mind, that, upon the appearance of the cause, they
immediately expect with assurance its usual attendant, and hardly conceive it
possible that any other event could result from it. It is only on the
discovery of extraordinary phaenomena, such as earthquakes, pestilence, and
prodigies of any kind, that they find themselves at a loss to assign a proper
cause, and to explain the manner in which the effect is produced by it. It is
usual for men, in such difficulties, to have recourse to some invisible
intelligent principle[iv]
as the immediate cause of that event which surprises them, and which, they
think, cannot be accounted for from the common powers of nature. But
philosophers, who carry their scrutiny a little farther, immediately perceive
that, even in the most familiar events, the energy of the cause is as
unintelligible as in the most unusual, and that we only learn by experience
the frequent Conjunction of objects, without being ever able to comprehend
anything like Connexion between them. 55. Here, then, many philosophers think themselves obliged
by reason to have recourse, on all occasions, to the same principle, which
the vulgar never appeal to but in cases that appear miraculous and
supernatural. They acknowledge mind and intelligence to be, not only the
ultimate and original cause of all things, but the immediate and sole cause
of every event which appears in nature. They pretend that those objects which
are commonly denominated causes, are in reality nothing but occasions; and
that the true and direct principle of every effect is not any power or force
in nature, but a volition of the Supreme Being, who wills that such
particular objects should for ever be conjoined with each other. Instead of
saying that one billiard-ball moves another by a force which it has derived
from the author of nature, it is the Deity himself, they say, who, by a
particular volition, moves the second ball, being determined to this
operation by the impulse of the first ball, in consequence of those general
laws which he has laid down to himself in the government of the universe. But
philosophers advancing still in their inquiries, discover that, as we are
totally ignorant of the power on which depends the mutual operation of
bodies, we are no less ignorant of that power on which depends the operation
of mind on body, or of body on mind; nor are we able, either from our senses
or consciousness, to assign the ultimate principle in one case more than in the
other. The same ignorance, therefore, reduces them to the same conclusion.
They assert that the Deity is the immediate cause of the union between soul
and body; and that they are not the organs of sense, which, being agitated by
external objects, produce sensations in the mind; but that it is a particular
volition of our omnipotent Maker, which excites such a sensation, in
consequence of such a motion in the organ. In like manner, it is not any
energy in the will that produces local motion in our members: It is God
himself, who is pleased to second our will, in itself impotent, and to
command that motion which we erroneously attribute to our own power and
efficacy. Nor do philosophers stop at this conclusion. They sometimes extend
the same inference to the mind itself, in its internal operations. Our mental
vision or conception of ideas is nothing but a revelation made to us by our
Maker. When we voluntarily turn our thoughts to any object, and raise up its
image in the fancy, it is not the will which creates that idea: It is the
universal Creator, who discovers it to the mind, and renders it present to
us. 56. Thus, according to these philosophers, every thing is
full of God. Not content with the principle, that nothing exists but by his
will, that nothing possesses any power but by his concession: They rob
nature, and all created beings, of every power, in order to render their
dependence on the Deity still more sensible and immediate. They consider not
that, by this theory, they diminish, instead of magnifying, the grandeur of
those attributes, which they affect so much to celebrate. It argues surely
more power in the Deity to delegate a certain degree of power to inferior
creatures than to produce every thing by his own immediate volition. It
argues more wisdom to contrive at first the fabric of the world with such
perfect foresight that, of itself, and by its proper operation, it may serve
all the purposes of providence, than if the great Creator were obliged every
moment to adjust its parts, and animate by his breath all the wheels of that
stupendous machine. But if we would have a more philosophical confutation of
this theory, perhaps the two following reflections may suffice. 57. First, it seems to me that this theory of the universal
energy and operation of the Supreme Being is too bold ever to carry
conviction with it to a man, sufficiently apprized of the weakness of human
reason, and the narrow limits to which it is confined in all its operations.
Though the chain of arguments which conduct to it were ever so logical, there
must arise a strong suspicion, if not an absolute assurance, that it has
carried us quite beyond the reach of our faculties, when it leads to
conclusions so extraordinary, and so remote from common life and experience.
We are got into fairy land, long ere we have reached the last steps of our
theory; and there we have no reason to trust our common methods of argument,
or to think that our usual analogies and probabilities have any authority.
Our line is too short to fathom such immense abysses. And however we may
flatter ourselves that we are guided, in every step which we take, by a kind
of verisimilitude and experience, we may be assured that this fancied
experience has no authority when we thus apply it to subjects that lie entirely
out of the sphere of experience. But on this we shall have occasion to touch
afterwards.[v] Secondly, I cannot perceive any force in the arguments on
which this theory is founded. We are ignorant, it is true, of the manner in
which bodies operate on each other: Their force or energy is entirely
incomprehensible: But are we not equally ignorant of the manner or force by
which a mind, even the supreme mind, operates either on itself or on body?
Whence, I beseech you, do we acquire any idea of it? We have no sentiment or
consciousness of this power in ourselves. We have no idea of the Supreme
Being but what we learn from reflection on our own faculties. Were our
ignorance, therefore, a good reason for rejecting anything, we should be led
into that principle of denying all energy in the Supreme Being as much as in
the grossest matter. We surely comprehend as little the operations of one as
of the other. Is it more difficult to conceive that motion may arise from
impulse than that it may arise from volition? All we know is our profound
ignorance in both cases.[vi] PART II.
58. But
to hasten to a conclusion of this argument, which is already drawn out to too
great a length: We have sought in vain for an idea of power or necessary
connexion in all the sources from which we could suppose it to be derived. It
appears that, in single instances of the operation of bodies, we never can,
by our utmost scrutiny, discover anything but one event following another,
without being able to comprehend any force or power by which the cause
operates, or any connexion between it and its supposed effect. The same
difficulty occurs in contemplating the operations of mind on body- where we
observe the motion of the latter to follow upon the volition of the former,
but are not able to observe or conceive the tie which binds together the
motion and volition, or the energy by which the mind produces this effect.
The authority of the will over its own faculties and ideas is not a whit more
comprehensible: So that, upon the whole, there appears not, throughout all
nature, any one instance of connexion which is conceivable by us. All events
seem entirely loose and separate. One event follows another; but we never can
observe any tie between them. They seem conjoined, but never connected. And
as we can have no idea of any thing which never appeared to our outward sense
or inward sentiment, the necessary conclusion seems to be that we have no
idea of connexion or power at all, and that these words are absolutely
without any meaning, when employed either in philosophical reasonings or
common life. 59. But there still remains one method of avoiding this
conclusion, and one source which we have not yet examined. When any natural
object or event is presented, it is impossible for us, by any sagacity or
penetration, to discover, or even conjecture, without experience, what event
will result from it, or to carry our foresight beyond that object which is
immediately present to the memory and senses. Even after one instance or
experiment where we have observed a particular event to follow upon another,
we are not entitled to form a general rule, or foretell what will happen in
like cases; it being justly esteemed an unpardonable temerity to judge of the
whole course of nature from one single experiment, however accurate or
certain. But when one particular species of event has always, in all
instances, been conjoined with another, we make no any scruple of foretelling
one upon the appearance of the other, and of employing that reasoning, which
can alone assure us of any matter of fact or existence. We then call the one
object, Cause; the other, Effect. We suppose that there is some connexion
between them; some power in the one, by which it infallibly produces the
other, and operates with the greatest certainty and strongest necessity. It appears, then, that this idea of a necessary connexion
among events arises from a number of similar instances which occur of the
constant conjunction of these events; nor can that idea ever be suggested by
any one of these instances, surveyed in all possible lights and positions.
But there is nothing in a number of instances, different from every single
instance, which is supposed to be exactly similar; except only, that after a
repetition of similar instances, the mind is carried by habit, upon the
appearance of one event, to expect its usual attendant, and to believe that
it will exist. This connexion, therefore, which we feel in the mind, this
customary transition of the imagination from one object to its usual
attendant, is the sentiment or impression from which we form the idea of
power or necessary connexion. Nothing farther is in the case. Contemplate the
subject on all sides; you will never find any other origin of that idea. This
is the sole difference between one instance, from which we can never receive
the idea of connexion, and a number of similar instances, by which it is
suggested. The first time a man saw the communication of motion by impulse,
as by the shock of two billiard balls, he could not pronounce that the one
event was connected: but only that it was conjoined with the other. After he
has observed several instances of this nature, he then pronounces them to be
connected. What alteration has happened to give rise to this new idea of
connexion? Nothing but that he now feels these events to be connected in his
imagination, and can readily foretell the existence of one from the
appearance of the other. When we say, therefore, that one object is connected
with another, we mean only that they have acquired a connexion in our
thought, and give rise to this inference, by which they become proofs of each
other's existence: A conclusion which is somewhat extraordinary, but which
seems founded on sufficient evidence. Nor will its evidence be weakened by
any general diffidence of the understanding, or sceptical suspicion
concerning every conclusion which is new and extraordinary. No conclusions
can be more agreeable to scepticism than such as make discoveries concerning
the weakness and narrow limits of human reason and capacity. 60. And what stronger instance can be produced of the
surprising ignorance and weakness of the understanding than the present? For
surely, if there be any relation among objects which it imports to us to know
perfectly, it is that of cause and effect. On this are founded all our
reasonings concerning matter of fact or existence. By means of it alone we
attain any assurance concerning objects which are removed from the present
testimony of our memory and senses. The only immediate utility of all
sciences, is to teach us, how to control and regulate future events by their
causes. Our thoughts and enquiries are, therefore, every moment, employed
about this relation: Yet so imperfect are the ideas which we form concerning
it, that it is impossible to give any just definition of cause, except what
is drawn from something extraneous and foreign to it. Similar objects are
always conjoined with similar. Of this we have experience. Suitably to this
experience, therefore, we may define a cause to be an object, followed by
another, and where all the objects similar to the first are followed by
objects similar to the second. Or in other words where, if the first object
had not been, the second never had existed. The appearance of a cause always
conveys the mind, by a customary transition, to the idea of the effect. Of
this also we have experience. We may, therefore, suitably to this experience,
form another definition of cause, and call it, an object followed by another,
and whose appearance always conveys the thought to that other. But though
both these definitions be drawn from circumstances foreign to the cause, we
cannot remedy this inconvenience, or attain any more perfect definition,
which may point out that circumstance in the cause, which gives it a
connexion with its effect. We have no idea of this connexion, nor even any
distinct notion what it is we desire to know, when we endeavour at a conception
of it. We say, for instance, that the vibration of this string is the cause
of this particular sound. But what do we mean by that affirmation? We either
mean that this vibration is followed by this sound, and that all similar
vibrations have been followed by similar sounds: Or, that this vibration is
followed by this sound, and that upon the appearance of one the mind
anticipates the senses, and forms immediately an idea of the other. We may
consider the relation of cause and effect in either of these two lights; but
beyond these, we have no idea of it.[vii]
As to the frequent use of the words, Force, Power, Energy,
&c., which every where occur in common conversation, as well as in
philosophy; that is no proof, that we are acquainted, in any instance, with
the connecting principle between cause and effect, or can account ultimately
for the production of one thing to another. These words, as commonly used,
have very loose meanings annexed to them; and their ideas are very uncertain
and confused. No animal can put external bodies in motion without the
sentiment of a nisus or endeavour; and every animal has a sentiment or
feeling from the stroke or blow of an external object that is in motion.
These sensations, which are merely animal, and from which we can a priori
draw no inference, we are apt to transfer to inanimate objects, and to
suppose, that they have some such feelings, whenever they transfer or receive
motion. With regard to energies, which are exerted, without our annexing to them
any idea of communicated motion, we consider only the constant experienced
conjunction of the events; and as we feel a customary connexion between the
ideas, we transfer that feeling to the objects; as nothing is more usual than
to apply to external bodies every internal sensation, which they occasion. 61. To recapitulate, therefore, the reasonings of this
section: Every idea is copied from some preceding impression or sentiment;
and where we cannot find any impression, we may be certain that there is no
idea. In all single instances of the operation of bodies or minds, there is
nothing that produces any impression, nor consequently can suggest any idea
of power or necessary connexion. But when many uniform instances appear, and
the same object is always followed by the same event; we then begin to
entertain the notion of cause and connexion. We then feel a new sentiment or
impression, to wit, a customary connexion in the thought or imagination
between one object and its usual attendant; and this sentiment is the
original of that idea which we seek for. For as this idea arises from a
number of similar instances, and not from any single instance, it must arise
from that circumstance, in which the number of instances differ from every
individual instance. But this customary connexion or transition of the
imagination is the only circumstance in which they differ. In every other
particular they are alike. The first instance which we saw of motion
communicated by the shock of two billiard balls (to return to this obvious
illustration) is exactly similar to any instance that may, at present, occur
to us; except only, that we could not, at first, infer one event from the
other; which we are enabled to do at present, after so long a course of
uniform experience. I know not whether the reader will readily apprehend this
reasoning. I am afraid that, should I multiply words about it, or throw it
into a greater variety of lights, it would only become more obscure and
intricate. In all abstract reasonings there is one point of view which, if we
can happily hit, we shall go farther towards illustrating the subject than by
all the eloquence and copious expression in the world. This point of view we
should endeavour to reach, and reserve the flowers of rhetoric for subjects which
are more adapted to them. |
[i] Section II
[ii] Mr. Locke, in his chapter of power, says that, finding from experience, that there are several new productions in matter, and concluding that there must somewhere be a power capable of producing them, we arrive at last by this reasoning at the idea of power. But no reasoning can ever give us a new, original, simple idea; as this philosopher himself confesses. This, therefore, can never be the origin of that idea.
[iii] It may be pretended, that the
resistance which we meet with in bodies, obliging us frequently to exert our
force, and call up all our power, this gives us the idea of force and power. It
is this nisus, or strong endeavour, of which we are conscious, that is the
original impression from which this idea is copied. But, first, we attribute
power to a vast number of objects, where we never can suppose this resistance
of exertion of force to take place; to the Supreme Being, who never meets with
any resistance; to the mind in its command over its ideas and limbs, in common
thinking and motion, where the effect follows immediately upon the will,
without any exertion or summoning up of force; to inanimate matter, which is
not capable of this sentiment. Secondly, This sentiment of an endeavour to
overcome resistance has no known connexion with any event: What follows it, we
know by experience; but could not know it a priori. It must, however, be
confessed, that the animal nisus, which we experience, though it can afford no
accurate precise idea of power, enters very much into that vulgar, inaccurate
idea, which is formed of it.
[iv] Theos apo mechanes (deus ex machina)
[v] Section XII
[vi] I need not examine at length the vis
inertiae which is so much talked of in the new philosophy, and which is
ascribed to matter. We find by experience, that a body at rest or in motion
continues for ever in its present state, till put from it by some new cause;
and that a body impelled takes as much motion from the impelling body as it
acquires itself. These are facts. When we call this a vis inertiae, we only
mark these facts, without pretending to have any idea of the inert power; in
the same manner as, when we talk of gravity, we mean certain effects, without
comprehending that active power. It was never the meaning of Sir Isaac Newton
to rob second causes of all force or energy; though some of his followers have
endeavoured to establish that theory upon his authority. On the contrary, that
great philosopher had recourse to an etherial active fluid to explain his
universal attraction; though he was so cautious and modest as to allow, that it
was a mere hypothesis, not to be insisted on, without more experiments. I must
confess, that there is something in the fate of opinions a little
extraordinary. Descartes insinuated that doctrine of the universal and sole
efficacy of the Deity, without insisting on it. Malebranche and other
Cartesians made it the foundation of all their philosophy. It had, however, no
authority in
[vii] According to these explications and
definitions, the idea of power is relative as much as that of cause; and both
have a reference to an effect, or some other event constantly conjoined with
the former. When we consider the unknown circumstance of an object, by which
the degree or quantity of its effect is fixed and determined, we call that its
power: And accordingly, it is allowed by all philosophers, that the effect is
the measure of the power. But if they had any idea of power, as it is in
itself, why could not they Measure it in itself? The dispute whether the force
of a body in motion be as its velocity, or the square of its velocity; this
dispute, I say, need not be decided by comparing its effects in equal or
unequal times; but by a direct mensuration and comparison.