PHL105Y Introduction to Philosophy Wednesday, November 29, 2006

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PHL105Y Introduction to Philosophy Wednesday,
November 29, 2006

• For next Mondays class, read to the end of
  section 5 of Humes Enquiry Concerning Human
  Understanding.
• Term test review questions are now available on
  the web, along with a sample term test. Test
  yourself. Ensure that you can answer those
  questions. This Friday is your last tutorial
  circle the hardest questions and ask your TA
  about them.
• For this Fridays tutorial, answer one of the
  following two questions, in about 200-250 words
  (about one typed double-spaced page) hand in the
  hard copy to your TA at the beginning of Fridays
  tutorial.
• How does Hume argue for the conclusion that all
  laws of nature are known only through experience,
  and not through pure reasoning?
• On page 19, Hume comments that the most perfect
  philosophy of the natural kind only staves off
  our ignorance a little longer. What does he
  mean by this?

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David Hume

• (1711-1776)
• An Enquiry Concerning Human Understanding --1748

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The origin of ideas

• Humes most general term perception
• There are two types of perceptions
• IMPRESSIONS (emotions, sensations, desires)
• IDEAS (thoughts of sensations, emotions, desires)

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Impressions and ideas

• Impressions the sensations I am now aware of,
  which have greater force and vivacity than the
  mere
• ideas or thoughts which memory or fantasy can
  conjure up.

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Simple and complex ideas

• Simple ideas (my recollection of the yellow of my
  living room walls, or of the smell of cinnamon)
  are (virtually) always faded copies of simple
  impressions (sensations, sentiments)
• Complex ideas might be copies of complex
  impressions (e.g. my recollection of the Toronto
  skyline) or they might be combinations of simple
  ideas (which are copies of simple impressions)
  e.g. my visualization of an alien landscape
  either way they can eventually be traced back to
  impressions

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All ideas come from impressions

• 1. You can take your existing ideas apart and
  trace them back to original sensations all
  thoughts and ideas can be analyzed into simple
  ideas copied from sensations.
• 2. People who dont have the corresponding simple
  impressions (whether because they lack the right
  faculty, or because they havent experienced the
  right object) will lack the ideas that result
  from those impressions.
• All simple ideas are copies of impressions.

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Wait, there might be an exceptionto that general
rule

• (just a little exception)

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An exception the missing shade of blue

• The rule all our ideas are copies of
  impressions, or combinations of copies of
  impressions
• Exception what if you had seen all shades of
  blue but one, and you arranged the shades you had
  seen in a row, minus the missing shade? Hume
  thinks that you could conceivably visualize the
  missing colour i.e. get a new simple idea that
  wasnt a copy of the corresponding impression.

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Can you imagine a colour you havent seen?

• Supersaturated red is not found in nature.
• It is red, but more intense than any shade of red
  you have seen before. Can you imagine that?
  (get an idea, where you have never had the
  corresponding impression)

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What does the missing shade of blue mean for the
general rule?

• Why do you think Hume included that exception to
  his own principle?
• Is it a significant exception?

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Even if we can add missing blues and reds

• Humes general point is that all our ideas
  ultimately come from experience.
• If experience allows us to patch in or
  extrapolate a few ideas just like those we
  ordinarily pick up in sensation, this fact
  doesnt undermine Humes general point about the
  kind of basis we have for all our ideas
  (especially abstract ones).
• Notice that the guy who gets the idea of the
  missing shade is driven by a special set of
  experiences to form that idea.

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Getting rid of empty jargon

• Do you suspect that a certain philosophical or
  metaphysical term might be meaningless?
• Hume wants you to ask yourself from what
  impression is that supposed idea derived? (13)

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Getting rid of empty jargon

• Do you suspect that a certain philosophical or
  metaphysical term might be meaningless?
• Hume wants you to ask yourself from what
  impression is that supposed idea derived? (13)
• Hume If you cant locate the appropriate
  impressions, your suspicions are confirmed

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Section III Of the association of ideas

• Hume thinks that chains of thought, however
  disorganized they might at first appear, can be
  explained
• What connections serve to bind together
  successive items in a train of thought?

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Principles of connectionamong ideas

• RESEMBLANCE
• CONTIGUITY in time or place
• CAUSE AND EFFECT

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Principles of connectionamong ideas

• RESEMBLANCE
• CONTIGUITY in time or place
• CAUSE AND EFFECT
• How does Hume come up with his list?

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Section 4 Sceptical Doubts

• The 2 sorts of issues we think about
• 1. RELATIONS OF IDEAS
• Geometry, algebra, arithmetic e.g. 6 is greater
  than 5 triangles have 3 sides
• 2. MATTERS OF FACT
• Empirical sciences, claims about particular
  objects copper conducts electricity Brutus
  killed Caesar

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Matters of fact

• Matters of fact cannot be discovered by pure
  reason why not?
• The contrary of every matter of fact is still
  possible because it can never imply a
  contradiction, and is conceived by the mind with
  the same facility and distinctness, as if ever so
  conformable to reality. (15)

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What is the basis of our thinking about matters
of fact?

• What enables us to think about any matter of fact
  beyond our present experience or memory?
• CAUSE AND EFFECT

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What is the basis of our thinking about matters
of fact?

• What enables us to think about any matter of fact
  beyond our present experience or memory?
• CAUSE AND EFFECT (How does that relation help us
  with Brutus killed Caesar?)

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Cause and effect

• Why is causation indispensable in grounding my
  belief that
• 1. my friend is now in France?
• 2. there has been another person on this desert
  island before me?
• 3. that the sound of talking I hear in the
  darkness means there are other people here?
• (Could any of these things be known without
  reliance on causal connections?)

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Cause and effect

• Why causal connections are always needed for
  factual knowledge
• If you were to ask a man, why he believes any
  matter of fact, which is absent for instance,
  that his friend is in the country, or in France
  he would give you a reason, and this reason would
  be some other fact as a letter received from
  him, or the knowledge of his former resolutions
  and promises.

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Cause and effect

• Why causal connections are always needed for
  factual knowledge
• If you were to ask a man, why he believes any
  matter of fact, which is absent for instance,
  that his friend is in the country, or in France
  he would give you a reason, and this reason would
  be some other fact as a letter received from
  him, or the knowledge of his former resolutions
  and promises. And here it is constantly
  supposed, that there is a connexion between the
  present fact and that which is inferred from it.
  Were there nothing to bind them together, the
  inference would be entirely precarious. (16)

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Cause and effect

• Knowledge of causation is not given a priori
  (from the things that go before, from pure
  reason), but a posteriori (from experience)
• Even the smartest person confronted with a
  totally new object will not know its causal
  powers Adam could not have known that water
  would suffocate him upon first looking at it, or
  that fire would hurt

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Cause and effect

• We fancy, that were we brought, on a sudden,
  into this world, we could at first have inferred,
  that one Billiard-ball would communicate motion
  to another upon impulse and that we needed not
  to have waited for the event, in order to
  pronounce with certainty concerning it. (18)
• Such is the influence of custom, that where it
  is strongest, it not only covers our natural
  ignorance, but even conceals itself, and seems
  not to take place, merely because it is found in
  the highest degree. (18)

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Cause and effect

• Pure reason on its own couldnt find any basis
  for the motion of those interacting billiard
  balls why dont they both just stop, or go
  sideways, or turn into smoke?
• Only experience informs us on this matter.

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Cause and effect

• every effect is a distinct event from its cause
  (19)
• Hume thinks that this is why we cant find
  ultimate causes of natural phenomena we can
  reduce the principles to a few general causes
  (perhaps elasticity, gravity, cohesion of parts),
  but we cant go further
• Why not?

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Cause and effect

• The most perfect philosophy of the natural kind
  only staves off our ignorance a little longer
  (19)
• What does Hume mean by that remark?
• Has he argued for it effectively?

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Part II a deeper analysis

• Reasoning about matters of fact depends upon the
  relation of cause and effect
• Our understanding of the relation of cause and
  effect depends upon experience
• But what is the basis of our drawing conclusions
  from experience?

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The problem of induction

• we always presume, when we see like sensible
  qualities, that they have like secret powers, and
  expect, that effects similar to those which we
  have experienced, will follow from them. (21)
• If you see something that outwardly resembles
  bread, you expect it to have the same secret
  powers of nourishing you.
• there is no known connection between the
  sensible qualities and the secret powers (21)

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The problem of induction

• We have tasted bread in the past, and found it
  nourishing we assume that it will continue to be
  that way in the future. How?
• Past experience tells us how things were how do
  we draw conclusions about future time from that?
  How do you know it is safe to eat lunch today?

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The problem of induction

• How do we know that nature will go on the same
  way?
• (or that nature will be uniform this gets
  called the principle of the uniformity of nature
  or PUN for short)

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The problem of induction

• How do we know that nature will go on the same
  way?
• Not through pure reason (because you can conceive
  of a change in the course of nature nothing in
  the sheer ideas forces you to accept that nature
  is uniform)

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The problem of induction

• How do we know that nature will go on the same
  way?
• not through experience either! (Why not?)

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The problem of induction

• We have said that all arguments concerning
  existence are founded on the relation of cause
  and effect that our knowledge of that relation
  is derived entirely from experience and that all
  our experimental conclusions proceed upon the
  supposition, that the future will be conformable
  to the past. To endeavour, therefore, the proof
  of this last supposition by probable arguments,
  or arguments regarding existence, must be
  evidently going in a circle, and taking for
  granted, which is the very point in question.
  (23)

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The problem of induction

• We have said that all arguments concerning
  existence are founded on the relation of cause
  and effect that our knowledge of that relation
  is derived entirely from experience and that all
  our experimental conclusions proceed upon the
  supposition, that the future will be conformable
  to the past. To endeavour, therefore, the proof
  of this last supposition by probable arguments,
  or arguments regarding existence, must be
  evidently going in a circle, and taking for
  granted, which is the very point in question.
  (23)

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The problem of induction

• All arguments from experience depend on the
  principle that nature is uniform
• So dont expect an argument from experience to
  prove that nature is uniform (that would be
  circular)

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The problem of induction

• When we think there is a causal connection
  between two types of event
• (A putting my hand in the fire B feeling
  pain), we believe that events of type A will
  always (must always) be followed by events of
  type B

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The problem of induction

• When we think there is a causal connection
  between two types of event (A putting my hand in
  the fire B feeling pain), we believe that
  events of type A will ALWAYS (must always) be
  followed by events of type B
• Is it a valid objection to say that we can
  believe in that causal connection even if
  sometimes (like when Ive shot my hand full of
  Novocain) I wont feel the pain?

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The problem of induction

• When we think there is a causal connection
  between two types of event (A putting my normal
  hand in the fire B feeling pain), we believe
  that events of type A will always (must always)
  be followed by events of type B
• Is it a valid objection to say that we can
  believe in that causal connection even if
  sometimes (like when Ive shot my hand full of
  Novocain) I wont feel the pain?
• No, because in that case Im not in fact working
  with an event of type A anymore Ive changed the
  initial set-up, and I have an event of type A
  instead. Believing in causal connections means
  that every time the initial set-up is of exactly
  the same type, the same effect will result.

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The problem of induction

• So, how do we come to believe that events of type
  A will always (must always) be followed by events
  of type B?
• Again, its not through pure reason its not as
  though we could deduce from looking that the
  whiteness and softness of bread that it would
  nourish us the substances secret powers have
  nothing to do with its outward appearance

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The problem of induction

• So, how do we come to believe that events of type
  A will always (must always) be followed by events
  of type B?
• Through REPEATED experience (but how can repeated
  experience tell us something that a single
  experience could not?)

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The problem of induction

• Why does this matter?
• If there be any suspicion, that the course of
  nature may change, and that the past may be no
  rule for the future, all experience becomes
  useless, and can give rise to no inference or
  conclusion. (24)

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The problem of induction

• Hume is clear that we DO think that nature is
  uniform he just wants to know why we think that.
• My practice, you say, refutes my doubts. But
  you mistake the purport of my question. .. As an
  agent, I am quite satisfied in the point but as
  a philosopher I want to learn the foundation of
  this inference. (24)

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The problem of induction

• Is some very subtle reasoning required to learn
  that nature is uniform?
• Hume notes that the most ignorant and stupid
  peasants, nay infants, nay even brute beasts,
  improve by experience, and learn the qualities of
  natural objects, by observing the effects, which
  result from them. (25)

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The problem of induction

• Hume wants to establish that reason doesnt (and
  in fact cant) establish that nature is uniform

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The problem of induction

• Hume wants to establish that reason doesnt (and
  in fact cant) establish that nature is uniform
• Our belief in the uniformity of nature is not
  rational (although for Hume this doesnt amount
  to saying we should give it up)