inference to matter of fact, any proof of an ‘instructive
proposition,’--as distinct from the conclusion of a syllogism,
which is simply derived from the analysis of a proposition already
conceded,--rests on the relation of cause and effect. Such language
implies that the relation is other than the inference, whereas, in
fact, they are one and the same, each being merely a particular
sort of sequence of feeling upon feeling--that sort of which the
characteristic is that, when the former feeling only has the maximum
of vivacity, it still, owing to the frequency with which it has been
attended by the other, imparts to it a large, though less, amount of
vivacity. This is the naked result to which Hume’s doctrine leads--a
result which, thus put, might have set men upon reconsidering the
first principles of the Lockeian philosophy. But he wished to find
acceptance, and would not so put it. A consideration of the points
in which he had to sacrifice consistency to plausibility--since he
was always consistent where he decently could be--will lead us to the
true αἴτιον τοῦ ψευδοῦς [1], the impossibility on his principles of
explaining the world of knowledge.
[1] [Greek αἴτιον τοῦ ψευδοῦς (aition tou pseudous) = the cause of
the error. Tr.]
Definitions of cause: a. As a ‘philosophical’ relation.
295. As the outcome of his doctrine, he submits two definitions
of the relation of cause and effect. Considering it as ‘a
_philosophical_ relation or comparison of two ideas, we may define a
cause to be an object precedent and contiguous to another, and where
all objects resembling the former are placed in like relations of
precedency and contiguity to those objects that resemble the latter.’
Considering the relation as ‘a _natural_ one, or as an association
between ideas,’ we may say that ‘a _cause_ is an object precedent and
contiguous to another, and so united with it that the idea of one
determines the mind to form the idea of the other, and the impression
of the one to form a more lively idea of the other’. [1]
[1] P. 464. [Book I, part III., sec. XIV.]
Is Hume entitled to retain ‘philosophical’ relations as distinct from
‘natural’?
296. Our first enquiry must be how far these definitions are really
consistent with the theory from which they are derived. At the
outset, it is a surprise to find that the ‘philosophical relation’
of cause and effect, as distinct from the natural one, should still
appear to survive. Such a distinction has no meaning unless it
implies a conceived relation of objects other than the _de facto_
sequence of feelings, of which one ‘naturally’ introduces the other.
It is the characteristic of Locke’s doctrine of knowledge that in it
this distinction is still latent. His language constantly implies
that knowledge, as a perception of relations, is other than the
sequence of feelings; but by confining his view chiefly to relation
in the way of likeness and unlikeness--a relation that exists
between feelings merely as felt, or as they are for the feeling
consciousness--he avoids the necessity of deciding what the ‘ideas’
are in the connection of which knowledge and reasoning consist,
whether objects constituted by conceived relations or feelings
suggestive of each other. But when once attention had been fixed, as
it was by Hume, on an ostensible relation between objects, like that
of cause and effect, which, if it exist at all, is clearly not one in
the way of resemblance between feelings, the distinction spoken of
becomes patent. If the colour red had not the likeness and unlikeness
which it has to the colour blue, the colours would be different
feelings from what they are; but if the flame of fire and its heat
were not regarded severally as cause and effect, it would make no
difference to them as feelings; or, to put it conversely, it is not
upon any comparison of two feelings with each other that we regard
them as related in the way of cause and effect. In what sense then
can the relation between flame and heat be a philosophical relation,
as defined by Hume--a relation in virtue of which we compare objects,
or an idea that we acquire upon comparison?
Examination of Hume’s language about them.
297. This definition, indeed, is not stated so exactly or so
uniformly as might be wished. In different passages ‘philosophical
relation’ appears as that in respect of which we compare any two
ideas; as that of which we acquire the idea by comparing objects, [1]
and finally (in the context of the passage last quoted) as itself
the comparison. [2] The real source of this ambiguity lies in that
impossibility of regarding an object as anything apart from its
relations, which compels any theory that does not recognize it to be
inconsistent with itself. It is Locke’s cardinal doctrine that real
‘objects’ are first given as simple ideas, and that their relations,
unreal in contrast with the simple ideas, are superinduced by the
mind--a doctrine which Hume completes by excluding all ideas that are
not either copies of simple feelings or compounds of these, and by
consequence ideas of relation altogether. The three statements of the
nature of philosophical relation, given above, mark three stages of
departure from, or approach to, consistency with this doctrine. The
first, implying as it does that relation is not merely a subjective
result in our minds from the comparison of ideas, but belongs to the
ideas themselves, is most obviously inconsistent with it according to
the form in which it is presented by Locke; but the second is equally
incompatible with Hume’s completion of the doctrine, for it implies
that we so compare ideas as to acquire an idea of relation other than
the ideas put together--an idea at once open to Hume’s own challenge,
‘Is it a colour, sound, smell, &c.; or is it a passion or emotion?’
[1] Cf. Part I. 5.
[2] P. 464. [Book I, part III., sec. XIV.]
Philosophical relation consists in a comparison, but no comparison
between cause and effect.
298. We are thus brought to the third statement, according to which
philosophical relation, instead of being an idea acquired upon
comparison, is itself the comparison. A comparison of ideas may seem
not far removed from the simple sequence of resembling ideas; but
if we examine the definition of cause, as stated above, which with
Hume corresponds to the view of the relation of cause and effect as
a ‘_philosophical_’ one, we find that the relation in question is
neither a comparison of the related objects nor an idea which arises
upon such comparison. According to his statement a comparison is
indeed necessary to give us an idea of the relation--a comparison,
however, not of the objects which we reckon severally cause and
effect with each other, but _(a)_ of each of the two objects with
other like objects, and _(b)_ of the relation of precedency and
contiguity between the two objects with that previously observed
between the like objects. Now, unless the idea of relation between
objects in the way of cause and effect is one that consists in, or
is acquired by, comparison _of those objects_, the fact that another
sort of comparison is necessary to constitute it does not touch the
question of its possibility. However we come to have it, however
reducible to impressions the objects may be, it is not only other
than the idea of either object taken singly; it is not, as an idea
of resemblance might be supposed to be, constituted by the joint
presence or immediate sequence upon each other of the objects. Here,
then, is an idea which is not taken either from an impression or from
a compound of impressions (if such composition be possible), and this
idea is ‘the source of all our reasonings concerning matters of fact.’
The comparison is between present and past experience of succession
of objects.
299. The modern followers of Hume may perhaps seek refuge in the
consideration that though the relation of cause and effect between
objects is not one in the way of resemblance or one of which the
idea is given by comparison of the objects, it yet results from
comparisons, which may be supposed to act like chemical substances
whose combination produces a substance with properties quite
different from those of the combined substances, whether taken
separately or together. Some anticipation of such a solution,
it may be said, we find in Hume himself, who is aware that from
the repetition of impressions of sense and their ideas new,
heterogeneous, impressions--those of ‘reflection’--are formed. Of
this more will be said when we come to Hume’s treatment of cause
and effect as a ‘natural relation.’ For the present we have to
enquire what exactly is implied in the comparisons from which this
heterogeneous idea of relation is derived. If we look closely we
shall find that they presuppose a consciousness of relations as
little reducible to resemblance, _i.e._ as little the result of
comparison, as that of cause and effect itself. It has been already
noticed how Hume treats the judgment of proportion between figures
as a mere affair of sense, because such relation depends entirely
on the ideas compared, without reflecting that the existence of the
figures presupposes those relations of space to which, because (as
he admits) they do not depend on the comparison of ideas, the only
excuse for reckoning any relation sensible does not apply. In the
same way he contents himself with the fact that the judgment of cause
and effect implies a comparison of present with past experience, and
may thus be brought under his definition of ‘philosophical relation,’
without observing that the experiences compared are themselves by
no means reducible to comparison. We judge that an object, which we
now find to be precedent and contiguous to another, is its cause
when, comparing present experience with past, we find that it always
has been so. That in effect is Hume’s account of the relation,
‘considered as a philosophical one:’ and it implies that the
constitution of the several experiences compared involves two sorts
of relation which Hume admits not to be derived from comparison,
_(a)_ relation in time and place, _(b)_ relation in the way of
identity.
Observation of succession already goes beyond sense.
300. As to relations in time and space, we have already traced out
the inconsistencies which attend Hume’s attempt to represent them
as compound ideas. The statement at the beginning of Part III.,
that they are relations not dependent on the nature of compared
ideas, is itself a confession that such representation is erroneous.
If the difficulty about the synthesis of successive feelings in
a consciousness that consists merely of the succession could be
overcome, we might admit that the putting together of ideas might
constitute such an idea of relation as depends on the nature of the
combined ideas. But no combination of ideas can yield a relation
which remains the same while the ideas change, and changes while
they remain the same. Thus, when Hume tells us that ‘in none of the
observations we may make concerning relations of time and place can
the mind go beyond what is immediately present to the senses, to
discover the relations of objects’ [1] the statement contradicts
itself. Either we can make no observation concerning relation in
time and place at all, or in making it we already ‘go beyond what
is immediately present to the senses,’ since we observe what is
neither a feeling nor several feelings put together. If then Hume
had succeeded in his reduction of reasoning from cause or effect to
observation of this kind, as modified in a certain way by habit,
the purpose for which the reduction is attempted would not have
been attained. The separation between perception and inference,
between ‘intuition’ and ‘discourse,’ would have been got rid of,
but inference and discourse would not therefore have been brought
nearer to the mere succession of feelings, for the separation between
feeling and perception would remain complete; and that being so, the
question would inevitably recur--If the ‘observation’ of objects
as related in space and time already involves a transition from
the felt to the unfelt, what greater difficulty is there about the
interpretation of a feeling as a change to be accounted for (which is
what is meant by inference to a cause), that we should do violence to
the sciences by reducing it to repeated observation lest it should
seem that in it we ‘go beyond’ present feeling?
[1] P. 376. [Book I, part III., sec. II.]
As also does the ‘observation concerning identity,’ which the
comparison involves.
301. Relation in the way of identity is treated by Hume in the third
part of the Treatise [1] pretty much as he treats contiguity and
distance. He admits that it does not depend on the nature of any
ideas so related--in other words, that it is not constituted by
feelings as they would be for a merely feeling consciousness--yet
he denies that the mind ‘in any observations we may make concerning
it’ can go beyond what is immediately present to the senses.
Directly afterwards, however, we find that there _is_ a judgment of
identity which involves a ‘conclusion beyond the impressions of our
senses’--the judgment, namely, that an object of which the perception
is interrupted continues individually the same notwithstanding the
interruption. Such a judgment, we are told, is a supposition founded
only on the connection of cause and effect. How any ‘observation
concerning identity’ can be made without it is not there explained,
and, pending such explanation, observations concerning identity
are freely taken for granted as elements given by sense in the
experience from which the judgment of cause and effect is derived.
In the second chapter of Part IV., however, where ‘belief in an
external world’ first comes to be explicitly discussed by Hume, we
find that ‘propensities to feign’ are as necessary to account for
the judgment of identity as for that of necessary connection. If
that chapter had preceded, instead of following, the theory of cause
and effect as given in Part III., the latter would have seemed much
less plain sailing than to most readers it has done. It is probably
because nothing corresponding to it appears in that later redaction
of his theory by which Hume sought popular acceptance, that the true
suggestiveness of his speculation was ignored, and the scepticism,
which awakened Kant, reduced to the commonplaces of inductive logic.
To examine its purport is the next step to be taken in the process
of testing the possibility of a ‘natural history’ of knowledge. Its
bearing on the doctrine of cause will appear as we proceed.
[1] P. 376. [Book I, part III., sec. II.]
Identity of objects an unavoidable crux for Hume. His account of it.
302. The problem of identity necessarily arises from the fusion of
reality and feeling. We must once again recall the propositions in
which Hume represents this fusion--that ‘everything which enters
the mind is both in reality and appearance as the perception;’
that ‘so far as the senses are judges, all perceptions are the
same in the manner of their existence;’ that ‘perceptions’ are
either impressions, or ideas which are ‘fainter impressions;’ and
‘impressions are internal and perishing existences, and appear
as such.’ If these propositions are true--and the ‘new way of
ideas’ inevitably leads to them--how is it that we _believe_ in ‘a
_continued_ existence of objects even when they are not present
to the senses,’ and an existence ‘distinct from the mind and
perception’? They are the same questions from which Berkeley derived
his demonstration of an eternal mind--a demonstration premature
because, till the doctrine of ‘ideas,’ and of mind as their subject,
had been definitely altered in a way that Berkeley did not attempt,
it was explaining a belief difficult to account for by one wholly
unaccountable. Before Theism could be exhibited with the necessity
which Locke claimed for it, it was requisite to try what could be
done with association of ideas and ‘propensities to feign’ in the
way of accounting for the world of knowledge, in order that upon
their failure another point of departure than Locke’s might be found
necessary. The experiment was made by Hume. He has the merit, to
begin with, of stating the nature of identity with a precision which
we found wanting in Locke. ‘In that proposition, _an object is the
same with itself_, if the idea expressed by the word _object_ were
no ways distinguished from that meant by _itself_, we really should
mean nothing.’ ‘On the other hand, a multiplicity of objects can
never convey the idea of identity, however resembling they may be
supposed. ... Since then both number and unity are incompatible with
the relation of identity, it must lie in something that is neither
of them. But at first sight this seems impossible.’ The explanation
is that when ‘we say that an object is the same with itself, we mean
that the object existent at one time is the same with itself existent
at another. By this means we make a difference betwixt the idea meant
by the word _object_ and that meant by _itself_ without going the
length of number, and at the same time without restraining ourselves
to a strict and absolute unity.’ In other words, identity means the
unity of a thing through a multiplicity of times; or, as Hume puts
it, ‘the invariableness and uninterruptedness of any object through a
supposed variation of time’. [1]
[1] Pp. 489, 490. [Book I, part IV., sec. II.]
Properly with him it is a fiction, in the sense that we have no
such idea. Yet he implies that we have such idea, in saying that we
mistake something else for it.
303. Now that ‘an object exists’ can with Hume mean no more than
that an ‘impression’ is felt, and without succession of feelings
according to him there is no time. [1] It follows that unity in the
existence of the object, being incompatible with _succession_ of
feelings, is incompatible also with existence in time. Either then
the unity of the object or its existence at manifold times--both
being involved in the conception of identity--must be a fiction; and
since ‘all impressions are perishing existences,’ perishing with a
turn of the head or the eyes, it cannot be doubted which it is that
is the fiction. That the existence of an object, which we call the
same with itself, is broken by as many intervals of time as there are
successive and different, however resembling, ‘perceptions,’ must be
the fact; that it should yet be one throughout the intervals is a
fiction to be accounted for, Hume accounts for it by supposing that
when the separate ‘perceptions’ have a strong ‘natural relation’ to
each other in the way of resemblance, the transition from one to
the other is so ‘smooth and easy’ that we are apt to take it for
the ‘same disposition of mind with which we consider one constant
and uninterrupted perception;’ and that, as a consequence of this
mistake, we make the further one of taking the successive resembling
perceptions for an identical, _i.e._ uninterrupted as well as
invariable object. [2] But we cannot mistake one object for another
unless we have an idea of that other object. If then we ‘mistake the
succession of our interrupted perceptions for an identical object,’
it follows that we have an idea of such an object--of a thing one
with itself throughout the succession of impressions--an idea which
can be a copy neither of any one of the impressions nor, even if
successive impressions could put themselves together, of all so
put together. Such an idea being according to Hume’s principles
impossible, the appearance of our having it was the fiction he had
to account for; and he accounts for it, as we find, by a ‘habit of
mind’ which already presupposes it. His procedure here is just the
same as in dealing with the idea of vacuum. In that case, as we saw,
having to account for the appearance of there being the impossible
idea of pure space, he does so by showing, that having ‘an idea of
distance not filled with any coloured or tangible object,’ we mistake
this for an idea of extension, and hence suppose that the latter
may be invisible and intangible. He thus admits an idea, virtually
the same with the one excluded, as the source of the ‘tendency to
suppose’ which is to replace the excluded idea. So in his account of
identity. Either the habit, in virtue of which we convert resembling
perceptions into an identical object, is what Hume admits to be a
contradiction, ‘a habit acquired by what was never present to the
mind’; [3] or the idea of identity must be present to the mind in
order to render the habit possible.
[1] ‘Wherever we have no successive perceptions, we have no notion of
time.’ (p. 342) [Book I, part II., sec. III.].
[2] P. 492. [Book I, part IV., sec. II.]
[3] P. 487. [Book I, part IV., sec. II.]
Succession of like feelings mistaken for an identical object: but the
feelings, as described, are already such objects.
304. The device by which this _petitio principii_ is covered is one
already familiar to us in Hume. In this case it is so palpable that
it is difficult to believe he was unconscious of it. As he has ‘to
account for the belief of the vulgar with regard to the existence
of body,’ he will ‘entirely conform himself to their manner of
thinking and expressing themselves;’ in other words, he will assume
the fiction in question as the beginning of a process by which its
formation is to be accounted for. The vulgar make no distinction
between thing and appearance. ‘Those very sensations which enter by
the eye or ear are with them the true objects, nor can they readily
conceive that this pen or this paper, which is immediately perceived,
represents another which is different from, but resembling it. In
order therefore to accommodate myself to their notions, I shall at
first suppose that there is only a single existence, which I shall
call indifferently _object_ and _perception_, according as it shall
seem best to suit my purpose, understanding by both of them what
any common man may mean by a hat, or shoe, or stone, or any other
impression conveyed to him by his senses’. [1] Now it is of course
true that the vulgar are innocent of the doctrine of representative
ideas. They do not suppose that this pen or this paper, which is
immediately perceived, represents another which is different from,
but resembling, it; but neither do they suppose that this pen or
this paper is a sensation. It is the intellectual transition from
this, that, and the other successive sensations to this pen or
this paper, as the identical object to which the sensations are
referred as qualities, that is unaccountable if, according to Hume’s
doctrine, the succession of feelings constitutes our consciousness.
In the passage quoted he quietly ignores it, covering his own
reduction of felt thing to feeling under the popular identification
of the real thing with the perceived. With ‘the vulgar’ that which
is ‘immediately perceived’ is the real thing, just because it is
not the mere feeling which with Hume it is. But under pretence of
provisionally adopting the vulgar view, he entitles himself to treat
the mere feeling, because according to him it is that which is
immediately perceived, as if it were the permanent identical thing,
which according to the vulgar is what is immediately perceived.
[1] P. 491. [Book I, part IV., sec. II.]
Fiction of identity thus implied as source of the propensity which is
to account for it.