David Hume’s Skepticism
The nature of ideas and reasoning concerning
‘matters of fact’
David Hume 1711-1776
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Prolific and successful
writer on philosophy,
history and economics;
published his Treatise
at the age of 26.
Never held a university
position (he was
suspected of atheism).
The French called him
‘le bon David’.
Empiricism
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Hume is called an empiricist, because of the
emphasis he and his fellow empiricists placed
on the contribution of experience to our
knowledge.
Descartes is called a rationalist: he and his
fellow rationalists emphasized the importance
of fundamental principles of thought that he
regards as a priori, that is, as knowable
independent of experience.
The source of ideas
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For Hume ideas are merely faint images or
copies of much more vivid experiences –
perceptions of the senses and emotional
states.
This difference in ‘liveliness’ (force or
vivacity) is the real difference between the
weaker states of mind we call ‘ideas’ and
other ‘perceptions of the mind’, which Hume
proposes to call ‘impressions’.
The imagination
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According to Hume we can freely combine
our ideas in almost unlimited ways.
But the basic materials that we combine and
rearrange so freely depend strictly on
experience, i.e. on having previously had an
impression, of which our idea is a kind of
pale, weak copy.
Consider the contrast between Hume’s
account of the idea of God and Descartes’.
Arguing for the view
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If you disagree, says Hume, give me an
example of an idea that doesn’t depend on
experience in this way!
We find, whenever someone lacks a sense
(sight, e.g.) or the opportunity to experience
something (the dry Laplander, the mild
mannered man), they also lack the
corresponding ideas.
One contrary case
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The missing colour:
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Given a complete sequence of shades with one
gap where a shade is omitted, we seem able to
imagine what that shade is like, i.e. to form the
idea of that shade.
Hume thinks this exception is so ‘singular’ that
the general principle should be retained.
What allows this to happen? Can we think of
any other such cases?
A method for inquiry
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Since impressions are always more lively and
clear, when we try to think about any idea (or
the meaning of any philosophical term), we
should always try to trace it back to the
‘impression from which it is derived’.
If we can’t do this, we are justified in
suspecting that the term ‘is employed without
any meaning or idea’.
Operations of the Understanding
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Relations of ideas:
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Geometry, Algebra, Arithmetic…
Affirmations that are ‘intuitively or
demonstratively certain’.
Matters of Fact:
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The contrary of these is possible.
Can’t demonstrate such facts (otherwise their
contraries would be contradictions and ‘could
never be distinctly conceived by the mind’).
The Sun
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The Sun will not rise tomorrow.
Though we’re sure this is false, we can’t
demonstrate that it is (to do so requires showing that
it’s somehow contradictory, but it isn’t: we can
distinctly conceive this happening).
So we have a puzzle: “(W)hat is the nature of that
evidence which assures us of any real existence and
matter of fact beyond the present testimony of our
senses or the records of our memory?”
Cause and Effect
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The basis of all reasoning concerning matters of fact.
This is the link that connects any present or
remembered facts to other facts that we infer from
them.
(It also links our memories to the facts they are
memories of.)
So how do we come by our knowledge of cause and
effect?
Hume says we have no a priori grounds for this–
only experience can do the job.
An argument
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No one can tell what the effects (or causes) of an
entirely new and unfamiliar sort of thing will be.
Adam could not have known, simply from looking at
it or feeling it, that water would suffocate him or fire
burn him.
Familiar causes and effects may seem, to us, to be
obvious– but only experience makes them so (the
billiard table).
How could the mind supply us with such
information on its own? There are no necessary
relations between (separate) facts!
Trouble
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Now, how do we reason from experience to our
conclusions about cause and effect?
Is this reasoning any good?
Hume is worried!
He says, ‘even after we have experience of the
operation of cause and effect, our conclusions from
that experience are not founded on reasoning or any
process of the understanding’. (225)
Like causes, like effects?
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“We always presume when we see like
sensible qualities that they have like secret
powers.”
Past experience applies only to those
particular objects and situations.
It just doesn’t follow that similar objects and
situations will produce similar results. No
reasoning justifies this expectation.
Experience and reason don’t do it.
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If something about a pattern of events shows
that the pattern was necessary, we should see
it (and be able to reason it out) the first time
we experience the pattern.
Yet we don’t reach the conclusion that the
pattern must be followed in every instance
when we first see it. We need repeated
experience to reach this conclusion.
What does needing repetition show?
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If some kind of argument links cause to effect,
then we should be able, once we’ve clearly
grasped the cause, to infer that the effect must
follow.
If the argument infers a ‘necessary
connection’ from the experience of a repeated
pattern, Hume asks what this ‘medium’
joining cause and effect is supposed to be, and
how repetition leads us to detect it?
Furthermore, it should be obvious
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Animals and babies clearly reach these kinds of
conclusions too.
So any reasoning (or experience) that tells us a
pattern will continue should be obvious when we
think about it.
“… if I be wrong (i.e.there is an argument linking
cause to effect)…I cannot now discover an argument
which…was perfectly familiar to me …before I was
out of my cradle.”
What could repetition add?
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Hume’s view is that the only thing repetition
of the pattern could do for us is to build a
pattern in us, a habit of regularly expecting
the effect whenever we witness the cause.
Hume concludes that the experience of
persistent, regular patterns leads us to form
this kind of habitual expectation.
But there’s no justification we can give for
this expectation; it really is just a habit.
The regress.
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Hume asks what sort of justification we could give,
of basing our expectations about the future on the
experience of regular patterns in the past.
The only justification available seems to be that
we’ve been successful, in the past, when we do this,
i.e. these expectations have proven right.
But that’s just another past pattern, and the question
here is what reason we have to think that past regular
patterns will continue into the future!
Skeptical Modesty
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Hume defends a skeptical response to this
puzzle.
Even though there is no reason to expect the
future to resemble the past, nature leads us to
this expectation.
A calm, skeptical attitude fits perfectly here:
we accept that we have no good reason for
this expectation, but we have the expectation
anyway.