Hume (休謨)
Outline 3—Causality 2
一、
The conclusion of the negative phase:
“That there is nothing in any object, considered in itself, which can afford us a
reason for drawing a conclusion beyond it; and, that even after the observation of
the frequent or constant conjunction of objects, we have no reason to draw any
inference concerning any object beyond those of which we have had experience.”
This is not a transition that ‘reason determines us to make’.
二、
Some natural, primitive dispositions of the mind
1. The search for dispositions or principles is empirical and experimental
investigation.
2. Constant conjunction and principle of union among ideas:
Given the constant conjunction between two sorts of things, we always come to
believe something about the unobserved in those circumstances because there is
operative in the human mind a ‘principle of union among ideas’.
3. The inevitable imagination that we find.
This union is not about reason but about imagination—that is, we come to an
inevitable effect that we create a union between the ideas of two constantly
conjoining sorts of objects or events.
There is no reason behind this union and we just (immediately & automatically)
find the idea of a B in our minds when we get an idea of an A. As a matter of fact,
we cannot easily prevent such an idea of B from occurring in such a situation.
4. What is missing from the picture?
There is something more than just producing an idea of B while giving an
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impression of an A and the constant conjunction of the two—we actually come to
believe that a B will occur.
5. The difficult question—what is the difference between ‘simple conception’
and belief?
The existence of disagreements manifests the difference between thinking or
conceiving or having an idea of something and believing that such-and-such is the
case. For I can conceive of what you say but disbelieve that it is true. In other
words, I can conceive of both sides of a dispute but only believe one of them.
三、
What is a belief? Believing something is not a further idea.
1. It is not an idea of reality or existence.
As we said in the discussion of Quinton’s words, there is not difference between
conceiving of the idea of something and the idea of the existence of something.
2. We do not add the idea of existence to another idea by believing it.
We can call up, unite and separate ideas at will. If believing something were
simply adding some idea of existence to the original idea, we could believe
whatever we want. But we cannot believe anything we want, for that would cause
contradiction.
3. As a question in natural philosophy, we must determine what the difference
between simple conception and belief is by experience and observation.
The union of imagination established by the observation of the constant
conjunction between As and Bs, whenever one of those ideas appears in the mind,
the other will follow. However, the mere idea of an A produces only the idea of a
B; it alone is not enough to make us believe that a B exists or will occur.
四、
Hume’s account of belief
1. Since belief differs from simple conception, believing must add something
to the original idea.
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As argued in the first two points of 三, believing does not add a further idea to the
original one, so what is added must be only a different manner of conceiving the
original idea. Any other change would change the idea conceived, and so it would
be impossible to conceive of and believe in the very same idea.
2. Impressions and ideas:
In order to get a belief that B will occur we must have an impression of an A.
Merely the union of the ideas of A and B wouldn’t do. That is, the idea of A would
not make us believe that a B will occur. An actual belief in the unobserved arises
only when make a transition from something observed or perceived.
Hume concludes that what distinguishes an idea or simple conception from a
belief is therefore whatever it is that distinguishes an impression from an idea. So
Hume feels he has no alternative but to say that a belief is a more vivid and
intense conception of an idea, proceeding from its relation to a present impression.
The general maxim in the science of human nature: when any impression
becomes present to us, it not only transports the mind to such ideas as are
related to it, but likewise to communicates to them as share of its force and
vivacity.
3. Two principles:
To make this explanation work, we need two principles. The first one is just that
the observed constant conjunction creates a union of imagination between things
of two kinds. The second principle is the transmission of force and vivacity from a
present impression to an associated idea.
Hume even suggests that his account results from common experience. But the
example he gave is extremely puzzling.
4. The explanation, the inference:
Since the difference in degrees of force and vivacity between an impression and
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an idea is the source of all the differences in the effects those two kinds of
perception have, and since an impression differs from an idea in having beliefs,
and not mere conceptions, as its effects, therefore a belief differs from an idea
only in its degrees of force and vivacity—the same difference between an idea and
an impression.
5. Theory of ideas:
So his search for the simplest and most general principles, explaining the
occurrence of beliefs, within the theory of ideas leads him astray. He cannot find a
definition in terms of other than those of force and vivacity because he thinks that
is the only difference in the manner of conceiving one and the same idea that the
theory of ideas allows.
五、
Hume’s own dissatisfaction with the account
1. Hume thinks that ‘greater force and vivacity’ does not really capture the
difference between a belief and a mere conception, but that there is a
difference in feeling between them that is very difficult to describe.
The variety of terms—a superior force, or vivacity, or solidity or firmness, or
steadiness—is intended only to express that act of the mind, which renders
realities more present to us than fictions, causes them to weigh more in the
thought, and gives them a superior influence on the passions and
imagination…But it is true and proper name is belief…and in philosophy we can
go no farther, than assert, that it is something felt by the mind, which distinguishes
the ideas of the judgement from the fictions of the imagination…and renders them
the governing principles of all our actions.
2. Belief and feeling:
What Hume does not have in mind is that believing something is simply to add
another mental item, namely, a feeling, to the original idea. It is rather in its
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effects—that is, the underlined expressions above—on the mind that an idea that is
a belief differs from a mere idea.
What Hume seems to miss is that this connection between belief and the passions
and the will might constitute the very difference he seeks between belief and mere
conception. In any rate, Hume is not the only one who did not do this but there is
still in short of such an account today.
3. Philosophy of mind:
The philosophy of mind Hume uncritically inherited, namely, the theory of ideas,
leaves no room for what has been called the ‘intentional’ character of thought or
psychological phenomena generally.
In distinguishing conceiving from believing he seems to be aware that one and the
same idea can be involved in different mental acts or modes of thinking.
六、
Custom and causal belief
1. The belief in the unobserved arises completely by ‘custom’
We do not decide to belief what we do; we are not free not o believe those things
that are most fundamental to us.
“Nature, by an absolute and uncontrollable necessity has determined us to judge
as well as to breathe and feel; nor can we any more forbear viewing certain
objects in a stronger and fuller light, upon account of their customary connection
with a present impression, than we can hinder ourselves from thinking as long as
we are awake, or seeing the surrounding bodies, when we turn our eyes towards
them in broad sunshine.”
Because of the inevitability of beliefs, it is impossible to put into practice a ‘total
scepticism’, or even a Cartesian ‘suspension of belief’.
The elevation of the importance of the primitive or natural dispositions of the
imagination lead to the conclusion:
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that all our reasonings concerning causes and effects are derived from nothing but
custom; and that belief is more properly an act of the sensitive, than of the
cogitative part of our natures.
2. Men and animals
Animals too act simply on the basis of past experience and their present
impressions. We do not inclined to suppose that they do so by deliberately
weighing evidence, considering the arguments on both sides, and then deciding to
adopt a certain conclusion (The italic part is just the claim of the traditional
theory of belief—cf. Causality 1, 六之 1). We are willing to agree that they just
find themselves with certain beliefs or expectations.
This is intended to break down the alleged difference in kind between men and the
other animals.
Hume denies Descartes’ theory that animals have no souls but only men have
spiritual substances. He thinks that men and animals are both the objects in
the natural world; both are subject to the same forces, and to influences of
the same general kind.
3. Reason is another instinct
In order to explain men’s beliefs and actions there is no need to invoke a
metaphysically detached faculty of ‘reason’ or ‘will’ operating independently of
those causal chains that make up the natural world.
“To consider the matter aright, reason is nothing but a wonderful and
unintelligible instinct in our souls, which carries us along a certain train of ideas,
and endows them with particular qualities, according to their particular situations
and relations.”
4. Causal inferences and necessary connection
Searching the source of the idea of necessary connection
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no impression of necessary connection in any particular instance of causality
the origin of this idea remains obscure
concentrating on the inference from the observed to the unobserved
Hume hints that:
“Perhaps it will appear in the end, that the necessary connection depends on the
inference, instead of the inference’s depending one the necessary connection.”
七、
Why the inference itself is not enough?
1. What has been done.
By explaining how we infer the unobserved from the observed, Hume identifies
and explains a pervasive and fundamental feature of the human mind. He has
shown how and why we come to have beliefs about the unobserved, and he has
indicated how important it is for human life that we do so.
2. Why dissatisfied then?
a. theory of ideas:
In terms of the beloved theory of ideas, every idea must come from impressions in
one way or the other. Although the account of inferences from the observed to the
unobserved has done its bits, we are still short of the origin of the idea of causality
or necessary connection.
b. necessary connection:
The account of the inferences from the observed to the unobserved only explains
why we expect a B will occur, when given that observing As’ being constantly
followed by Bs, and while an A presents. However, coming to believe that a B will
occur is awfully different from coming to believe that a B must occur. In other
words, the account provided by our discussion in Causality-1 does not really
explain why there is necessary connection within causality.
c. How come the idea of necessary connection arises from the repeated
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observations of Bs following As?
Constant conjunction between As and Bsthe inference from cause to effect
within each instance of the constant conjunctionno trace of the impression or
the idea of causality or necessary connection
only by repeated observations of Bs following Aswe have the idea of
necessary connection
each instance is independent in the sense that no one of them will influence or
be influenced by anotherif there is no trace within one instance there is no trace
within any of them.
Then, how can we arrive at an idea of necessary connection?
八、
There must be something new.
1. Why something new?
It is a fact that we do have the idea of necessary connection (between causes and
effects).
There must be an origin of this idea.
It is also a fact that this has to do with the observation of constant conjunction
between two sorts of objects or events.
There is nothing in the instances observed.
Repetition, we know, produces the idea of necessary connection in minds that
originally lack it.
According to the theory of ideas, it follows that something else must be
produced in the mind, and that that thing is an impression.
Since there is nothing in the instances observed, it must not be an impression of
sensation but one of reflection.
But what is it?
2. An internal impression of the mind?
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“For after we have observed the resemblance in a sufficient number of instances,
we immediately feel a determination of the mind to pass from one object to its
usual attendant, and to conceive it in a stronger light upon account of that relation.
This determination is the only effect of the resemblance; and therefore must be the
same with power or efficacy, whose idea is derived from the resemblance. The
several instances of resembling conjunctions lead us into the notion of power and
necessity. Those instances are in themselves totally distinct from each other, and
have no union but in the mind, which observes them, and collects their ideas.
Necessity, then, is the effect of this observation, and is nothing but an internal
impression of the mind, or a determination to carry our thoughts from one object
to another.”
a. The clear part:
The only thing new after the repeated observations is a ‘determination of the mind
to pass from one object to its usual attendant, and to conceive it in a stronger light
upon account of that relation’.
That is, when one repeatedly observes the constant conjunction between As and
Bs and are currently observing an A, we are led to get and idea of, and a belief in,
a B. So the first complex mental event (the first two conditions happen)
causes the second mental event (believing that a B will occur). When this
happens we get the idea of necessary connection between As and Bs; that
explains how and why that idea arises in the mind.
b. The confusion:
Why necessity is ‘an internal impression of the mind’, or ‘a determination to carry
our thought from one object to another’?
The idea of necessity or necessary connection, Hume seems to argue, only comes
into the mind as a result of one mental occurrence’s causing another, and
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according to the theory of ideas the source or cause of an idea is an impression, so
the one event’s causing the other is the impression from which the idea of
necessary connection is derived.
However, this is incoherent. One event’s causing another cannot be an
impression, even if we do have impressions of the occurrences of these mental
events.
Hume sometimes does say that ‘we immediately feel a determination of the mind,’
and this suggests that we feel, or are aware of, the one event’s causing the other.
But this cannot be construed as we have an impression of the causal or necessary
connections. For this is explicitly denied by Hume, even if it is for two mental
events.
c. The clarification and the new perplexity:
It is not just the idea of, and a belief in, a B we get, given that some appropriate
conditions are satisfied, but also that the idea appears in the mind accompanied by
a certain feeling—a feeling of something like determination or inevitability.
This feeling is more significant than it seems to be, for the impression of it
does not accompany the first several instances of As’ being followed by Bs; it
begins to accompany the idea of a B only after repeated observations.
So it is not an impression of something that is present in each individual
instance. Since it is an impression arising only from the repeated occurrence
of certain kinds of ideas in the mind, and therefore it must be classified as an
impression of reflection.
But what does this special feeling or impression of the inevitability with which
something occurs differ from an impression of the occurrence of something itself?
What is the extra element that makes it special?
It was already stated that it cannot be said that it is an impression of the
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occurrence’s being caused, or of the necessary connection.
九、
Necessity and external objects
“Upon the whole, necessity is something, that exists in the mind, not in objects;
nor is it possible for us ever to form the most distant idea of it, considered as a
quality in bodies. Either we have no idea of necessity, or necessity is nothing but
that determination of the thought to pass from causes to effects and from effects to
causes, according to their experienced union.”
1. Existing in the mind?
When Hume says the first sentence, he is not saying that causality only operates in
the inner mental world. If it were a conditioning of having the idea of necessity
that we get it from discovering the real causes or the secret springs of the
correlations we observe, then we could never have the idea. But we do have an
idea of necessity, so its origin must be accounted for solely in terms of happenings
in our minds.
2. The content of the idea of necessity and the origin of this idea
In many places, Hume seems to conflate two different questions regarding the
idea of necessity—its content and its origin.
One possible reason is because of the beloved theory of ideas, according to
which the origin of an idea can be used to explain its content, insofar as the
impression by which the idea is derived gives it the power and efficacy.
If this is the case, however, the idea of necessity has to be a simple one, for,
according to the theory of ideas, only simple ideas have their origins as the
corresponding impressions.
Moreover, this simple impression is not about some feature of the world that
presents itself to us. This holds just as much for the ‘inner’ mental world as for the
‘outer’ world of objects and events.
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As mentioned in 八 (2), if the determination of the mind is what causes us
to have the idea of necessity, then the first principle of the theory of ideas that
simple ideas are derived from simple impressions have been violated. For a
determination as such is not an impression. So the idea of necessity has to be
caused by the impression or feeling of that determination.
This feeling or impression is not of that one event’s causing the other, or of
the necessary or causal connection between them; it is just a peculiar feeling
that accompanies, or is simultaneous with, the occurrence of that second
event in the mind, presumably after a large amount of repeating instances.
And this occurrence is as always not what Hume would explain.
3. The analogy with second qualities:
Just like that redness is not something actually resides in objects or the
connections between them, necessity or causality is not either.
We ascribe redness to certain things in the world only because something
happens in our minds when we observe things that, according to the traditional
theory, actually possess no redness.
Similarly, we ascribe necessity to certain things in the world only because
something happens in our minds when we observe things (, that is, correlations
and conjunctions,) that possess no necessity.
Sounds and smells, Hume says, ‘really exist nowhere’, and the same holds for
necessity.
4. The ascription of redness or necessity to objects or connections of events in
the outer world
When we ascribe redness to objects, we have a false belief that it resides in
objects in the outer world. But we could not possibly ascribe the impression of
redness to objects. That is utterly absurd.
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Similarly, when we believe that there are necessary connections between
events in the world, we have false beliefs. And it would be absurd to say that
necessity just is an impression in the mind, or our idea of necessity is just the
idea of something in the mind, since when we ascribe necessity to the
connection between two events we are not saying something about our own
minds.
Because of the mind’s natural tendency to ‘spread itself’ on external objects,
when we get a ‘feeling of determination’ we then come to project necessity
onto the objective relations between events in the world, and thus come to
believe, mistakenly, that there are objective necessary connections between
events.
十、
Necessity and the idea of necessity
1. Something illuminating
The above explanation is probably unsatisfactory because at the end of the day it
does not provide us with any account of what the content of the idea of necessity
is.
The problem is more severe than this. For we cannot say anything illuminating or
helpful about what any given simple idea is. So this is not peculiar about the idea
of necessity. The genuine problem is that it is difficult to say what does having the
idea of necessity make any difference. This is why Hume concentrates more on
the explanation of how we come to possess such an idea of necessary connection,
than on what the idea is or is about.
2. Something not illuminating
The idea of necessity is produced by an impression. If one wants to know why this
impression produces this idea, then Hume’s answer would be that is because it is
the idea of necessity but not something else, such as the idea of Chia-Yi or of 101
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Building, that it produces, and it is because it is the impression of necessity or
determination.
But this is very unsatisfactory. Hume deliberately says nothing about the
causes of our impressions—his theory of the mind simply starts with them. So
in general he ignores the question of why some particular impression is said
to be an impression of X. But in the case of necessity he does not simply
ignore the question, he is precluded from answering it, since he cannot say
that its being an impression of necessity consists in its being an impression
derived from an instance in which necessity is exhibited, something that we
can find in cases such as red. The idea is known to be an idea of necessity only
because it is derived from an impression of necessity, and the impression is
known to be an impression of necessity only because it gives rise to the idea of
necessity.
3. Two definitions
a. We may define a cause to be ‘An object precedent and contiguous to another,
and where all the objects resembling the former are placed on like relations of
precedency and contiguity to those objects, that resemble the latter.’ (Treatise, p.
170)
b. A cause is an object precedent and contiguous to another, and so united with it,
that the idea of the 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. (ibid.)
*Two definitions characterise causality as different relations, philosophical and
natural. Philosophical relations are those such as spatial or temporal relation.
Natural relations are those about the relation between two events such as one’s
hand-raising here and the thunder roaring fifty years ago in Sydney or the broken
pieces of a glass and its falling from the table—there is no natural relation within
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the former but there is within the latter.
*For Hume, resemblance, contiguity, and causality are the only three that are
both philosophical and natural relations.
*These two definitions are not equivalence and neither one implies the other.
The first one is a relation of constant conjunction that does not rely on the
existence of minds, while the latter has to recur to the existence of minds (cf.
those words with curve underline in b). And strictly speaking, they are not
definitions, or is intended by Hume to be an equivalence which express the full
and precise meaning of ‘X causes Y’.
4. Why then put forward these two?
The particular relation between a and b is that any events or objects observed
to fulfil the condition of a are such that they will fulfil the conditions of b. An
observed constant conjunction between As and Bs establishes a ‘union in the
imagination’ such that the thought of an A naturally leads the mind to the thought
of a B. That is just a fundamental, but contingent, principle of the human
mind.
Hume thinks he has shown that it is only because things fulfil the conditions of b
that any things in the world are thought to be related causally or necessarily at all.
We get the idea of necessary connection only because of the passage of the mind
from the thought of something to the thought of it ‘usual attendant’. That is
perhaps why he feels constrained to include something like the second
‘definition’, b, in any attempt to characterise our idea of causality. It is only
because causality is in fact a ‘natural’ relation that we ever manage to get the
idea of it at all.
5. The relation between the two definitions
Since it is a contingent fact that we get what we get and how we get for the idea of
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necessity, or that we get it at all. (cf. point 4) Therefore, it is possible that there are
people just like us, except they only get different appreciation of a and b. They
might get the constant conjunction between As and Bs, and thus the ‘union in
imagination’ between As and Bs, so that the thought of an A naturally leads the
mind to the thought of B, except they do not get from that transition of mind
(between the thoughts of A and B) the idea of, and thus a belief in, a necessary
connection between As and Bs.
It follows that, for them, not like us, a B will, instead of must, occur when an
impression of A is given.
Why do we need the second definition? The above characterisation shows
that they do not actually believe the same thing as we do, for the necessary
connection between As and Bs is not part of their understanding of the
philosophical relation between them. Therefore, Our belief that two events
are causally connected is not fully captured by the first definition, a. We need
the second one, b, to implant the needed natural relation.
Why then the first definition is unexpendable? Because it is about all the
objective relations that actually hold between events we regard as being
causally related.
6. Does the second definition get the explanation down?
If the second definition is what there is for us to give an explanation of why we
come to have the idea of necessity, does it get the explanatory work down?
Stroud argues at length to explain why this is not doable, for this makes
Hume fall a prey to subjectivism or psychologism.
Admittedly, there is not much to be said about what the idea of necessity is,
and nothing Hume says can be taken as a strict definition of the notion, but
that is as it should be for a simple idea. The two ‘definitions’ are intended to
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help us get as close to it as we can, but it is an idea that we cannot be given by
definition or explanation at all. All that can be according to Hume, it seems, is
that we either have it or we don’t, and that we get it only after having the
appropriate kind of experience.
十一、 Mixed blessing
1. Does Hume’s scepticism hit himself hard?
As repeatedly argued, Hume’s account of causality is itself a causal explanation of
how we come to have that idea. It follows that his own account of causality
might suffer from his sceptical argument as well. That is, Hume’s account
based on the claim that there is an observed constant conjunction between two
mental phenomena: (C) the occurrence of an impression of an A in a mind that has
already observed a constant conjunction between As and Bs, and (E) that mind’s
getting a belief that a B must occur.
The objection to Hume presumably does not deny that this is a
straightforward observable fact of human minds. But, on Hume’s own
sceptical grounds, those data (those observed constant conjunctions between
Cs and Es) give us no reason to believe Hume’s theory to that effect that (C)
causes (E).
Stroud’s reply: If Hume’s theory is true, that whenever we observed a (C) we
come to believe that a (E) must occur.
Then anyone who agrees that there is in fact a constant conjunction between (C)
and (E) will come to believe Hume’s theory.
Because this is the outright consequence of Hume’s theory.
So the objection comes to nothing more than a kind of pedantic bad faith.
To criticise that there is no reason to hold the inference of (OU) does not
prevent one to pursue the science, or, in other words, the moral philosophy of
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human. If it is the case that the necessary connection between (PE), (PI), and
(FE) is due to the feeling of a determination of our mind, then there is no
reason to question Hume’s theory based on his previous sceptical grounds.
2. Is this the correct observation that (C) causes (E)?
This is questioning whether the data of Hume’s theory is correct.
Is it true that we are inevitably having the feeling of a determination to carry
our thought from one object to another?
Hume seems to suggest that it is inevitable for us to do this whenever observed
repeated instances of constant conjunctions. This is, however, very implausibly.
For instance, if you observe 30 times of tossing coins and the resulting in a head
always, will you come to believe inevitably that a head must follow from a next
toss?
Further, if we failed to find any objective relation held within any constant
conjunctions, are we not coming to the conclusion that all of this is just accidental?
3. The genuine problem
Nelson Goodman raises what he calls ‘the new riddle of induction’.
After observing a lot of emeralds, we find that they are all green. Then according
to Hume’s theory, we would be led to believe that the next emerald we observe
will be green, or even all emeralds are green. Considering another predicate ‘grue’
whose definition is as follows:
X is grue (gr(-een)(bl-)ue) iff (if and only if) it is first observed before 2050 A.D.
and it is green; or it is observed at or after 2050 A.D. and it is blue.
Therefore, we can also say that all emeralds observed so far are grue. However,
this leads us to contradictory beliefs that all emeralds are both green and grue
while clearly the two predicates are not synonymous. We do not even need such a
eccentric predicate to establish the criticism, for it is very likely in real life people
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describe some instances as belonging to one class and some other people describe
the same set of instances as belonging to another different class. And this leads us
to expect whatever outcome we please to expect because of the contradiction.
4. It is not that Hume is completely wrong in his account of the origin of our
beliefs in the unobserved, but only that what he says, even if correct, cannot
be the whole story.
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