Issues in Philosophy

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Issues in Philosophy

• Guy Longworth
• g.longworth_at_mac.com

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Stepping back

• We began with a large issue, or range of issues,
  concerning the subjective, the objective, and
  relations between them.

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Stepping back

• With these issues as background, weve looked at
• The status of ethics

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Stepping back

• The status of ethics
• Mackie Can we make sense of the idea that
  ethical value is objective, part of the fabric of
  reality? If not, how should we understand ethical
  judgements? How should we understand ethical
  dispute, which appears to treat ethical
  judgements as though they aimed to track an
  independently constituted ethical reality?

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Stepping back

• The status of ethics
• Moore Is there space for an account of ethical
  value in other terms? In particular, is it
  possible to account for ethical value in terms of
  our subjective features? Or is it rather that the
  Open Question argument demonstrates that no
  such account can be given?

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Stepping back

• The status of philosophy
• Logical positivists Philosophical claims are
  either substantive claims about objective
  reality, in which case they are really scientific
  or empirical claims or, they are analytic
  trivialities.

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Stepping back

• The status of philosophy
• Quine The Logical positivists distinction
  between analytic and synthetic claims has no
  merit. Philosophical claims are substantive in
  the same way as scientific claims, since
  philosophy and science are continuous.

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Stepping back

• The status of philosophy
• Both views about philosophy restrict the
  pretensions of what we might think of as pure
  philosophy philosophy based solely upon
  reflection. They both reject the idea that
  reflection alone might deliver substantive
  knowledge.

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Stepping back

• The status of philosophy
• If we assume that, in the first instance,
  reflection traces the contours of our own
  subjectivity, by following the lines of our own
  concepts, ideas, meanings, then we can view this
  point of agreement as restricting the pretensions
  of subjectivity-bound reflection to deliver
  conclusions about objective reality.

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Stepping back

• The status of philosophy
• With that in mind, we returned to a seemingly
  substantive topic about which philosophers have
  traditionally had something to say, and have
  often aimed to say it on the basis of reflection
  the existence of God.

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Stepping back

• The existence of God
• Here, we really face three questions
• Q1. What does the claim God exists mean?
• Q2. Is the claim, so understood, true?
• Q3. Can we decide Q2. on the basis of reflection?

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Stepping back

• The existence of God
• Q3. Can we decide Q2. on the basis of reflection?
• A way of understanding this question is Can
  reflection on the contours of our
  subjectivity--our concepts--deliver substantive
  conclusions about objective reality?

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Stepping back

• The existence of God
• Q3. Can we decide Q2. on the basis of reflection?
• A way of understanding this question is Can
  reflection on the contours of our
  subjectivity--our concepts--deliver substantive
  conclusions about objective reality?

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Stepping back

• The existence of God
• Q1. What does the claim God exists mean?
• One way of understanding this question is as
  providing a place for reflection to play a role,
  if it cant deliver knowledge about objective
  reality.

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Stepping back

• The issues weve looked at thus far have in
  effect concerned the question How do features of
  our subjectivity, and so reflection which appears
  bound up with those features, bear on the nature
  of objective reality?
• The next issue moves in the opposite direction
  How do features of objective reality bear on the
  nature of our subjectivity?

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Physicalism

• Objectivism Everything there is is (ultimately)
  objective if something would be subjective, if
  it existed, then it is a figment.

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Physicalism

• Two immediate unclarities in Physicalism
• Physicalism is bound up with physics. Two
  options
• (1a) Current physics tells us what there is.
• What might be wrong with that?

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Physicalism

• Two immediate unclarities in Physicalism
• (1a) Current physics tells us what there is.
• The main problem is that we have no immediate
  reason to think that current physics is close to
  complete. Current physics contains elements
  undreamt of in 19th Century physics. Why think
  our physics is dramatically closer to exhausting
  what there is?

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Physicalism

• Two immediate unclarities in Physicalism
• (1b) Future (completed) physics tells us what
  there is.
• What might be wrong with that?

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Physicalism

• Two immediate unclarities in Physicalism
• One problem with this view is that, absent
  further specification, its not clear that it
  rules anything out. Perhaps, for example, a
  complete physics would have to make reference to
  ghosts, God, unicorns, etc.
• Perhaps none of that is plausible. But really
  this is an empirical question, or appears to be.
  Absent further work, its not clear what
  Physicalism of this stripe would rule out.

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Physicalism

• Two immediate unclarities in Physicalism
• Unclarity (2)
• (2) What is Physicalism a claim about?

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Physicalism

• Two immediate unclarities in Physicalism
• Things What singular terms pick out
• What Bill and The table pick out in (1) and
  (2)
• Bill smokes
• The table is brown

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Physicalism

• Two immediate unclarities in Physicalism
• Properties What predicates pick out
• What smokes and is brown pick out in (1) and
  (2) (or what nominalisations of predicates pick
  out as in (3) and (4)
• Bill smokes
• The table is brown
• The property of being a smoker
• The property of being brown

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Physicalism

• Two immediate unclarities in Physicalism
• Facts What whole sentences pick out (or what
  nominalisations of whole sentences pick out)
• What (1) and (2) pick out, as in (4) and (5)
• Bill smokes
• The table is brown
• The fact that Bill smokes
• (5) The fact that the table is brown

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Physicalism

• Two immediate unclarities in Physicalism
• Is the idea that there are no non-physical things
  (e.g. objects, particular, things we use singular
  terms to talk about), no non-physical properties
  (e.g. things we use predicates to talk about), or
  no non-physical facts (e.g. things we use
  sentences to talk about)?

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Physicalism

• Two immediate unclarities in Physicalism
• Different forms of Physicalism result depending
  on ones answer to this question.
• Well return to why this might matter to the
  issue about the place of subjectivity.

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Physicalism

• Two immediate unclarities in Physicalism
• A related but more specific question about the
  coverage of Physicalism concerns whether it is
  supposed to include everything (of whatever
  general categories it is supposed to cover), or
  just everything meeting some additional condition.

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Physicalism

• Two immediate unclarities in Physicalism
• For instance, a very strong form of Physicalism
  would rule out everything non-physical.
• But that would appear to rule our mathematical
  reality.
• (Assuming that maths is a substantive subject
  matter, and not a set of analytic trivialities.)

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Physicalism

• Two immediate unclarities in Physicalism
• An alternative would be to restrict Physicalism
  to spatio-temporal affairs stuff that happens
  and interacts with other stuff that happens.
• Thats the usual understanding of Physicalism,
  and the one well adopt.

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Physicalism

• Why might one accept Physicalism?

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Physicalism

• Why might one accept Physicalism?
• A variety of reasons
• Success of physics thus far in capturing what
  there is.
• E.g., explanation of chemical and biological
  facts by appeal to physics.
• This might lead to an optimistic induction
  perhaps everything can be explained in the same
  sort of way.

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Physicalism

• Why might one accept Physicalism?
• (2) Objectivism
• If one accepts Objectivism, one might view
  Physicalism as a way of ensuring that all that
  there is is objective, because physical.

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Physicalism

• Why might one accept Physicalism?
• (3) Causal interaction with physical elements
• A common reason for endorsing Physicalism is some
  version of the following argument

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Physicalism

• Consider some subject matter with elements that
  have causal effects on physical elements, e.g.
  psychology. Now,
• (P1) All physical effects have physical causes
  (the domain of the physical is causally complete,
  or causally closed).
• (P2) Hence, the effects of our target
  elements--e.g., psychological states or
  episodes--have physical causes.
• (P3) But we shouldnt allow that physical effects
  are globally overdetermined--that they have more
  than one cause.
• (P4) The only way to avoid global
  overdetermination (given (P1)-(P3)) is to
  identify the elements of the target subject
  matter--e.g. psychological states and
  episodes--with physical elements.

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Physicalism

• According to this argument we face a simple
  decision
• EITHER
• Identify elements of our target subject matter
  with physical elements
• OR
• (b) Give up the claim that those elements have
  physical effects, so endorse a view known as
  epiphenomenalism.

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Physicalism

• So, there are some general considerations and a
  powerful seeming argument in favour of
  Physicalism.
• Question What should be done about the
  subjective realm?

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Physicalism

• Q1. Is the subjective realm to be identified with
  the physical realm?
• Yes We can be realists about the subjective and
  also Physicalists.
• No We face further questions

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Physicalism

• Q2. Is the subjective realm real?
• No We can be Physicalists (but then we have to
  explain away the appearance of the subjective
  realm and wont the appearance itself be a
  subjective element)
• Yes We face further questions

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Physicalism

• Q3. Is the subjective realm causally efficacious?
• No We can be epiphenomenalists, but have to give
  up Physicalism.
• Yes We have to give up Physicalism, and also
  find an answer to the central argument for
  Physicalism, from causal closure.

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Against Physicalism

• Frank Jackson has offered an argument against
  Physicalism.
• Sketch
• (P1) There are facts about the subjective realm.
• (P2) Some of those facts are not physical facts.
• (C3) There are non-physical facts.
• (C4) Physicalism is false.

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Against Physicalism

• Subjective facts
• What its like to experience
• There is something its like to see a red rose,
  eat marmite, smell coffee, etc.

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Against Physicalism

• Subjective facts
• Were supposed to know about this what its
  likeness by experience, or by reflecting on our
  experience.

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Against Physicalism

• Subjective facts
• Once we have focused upon what its like,
  Jackson will argue that it is obvious that what
  its like is not captured in the Physicalists
  net.

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Against Physicalism

• Mary
• A thought experiment
• Mary is a future super-scientist who has been
  confined since birth in a black and white room,
  so never exposed to chromatically coloured
  objects. Her confinement hasnt limited her
  acquisition of scientific--physical--knowledge.
  She has learned everything there is to know about
  the physics of colour vision.

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Against Physicalism

• Mary
• A thought experiment
• As Jackson points out, theres no immediate
  reason to think that thats impossible. She can
  have full access to subjects who are seeing
  colours, via black and white monitors.

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Against Physicalism

• Mary
• A thought experiment
• Eventually, Mary gets bored (or has completed her
  task), so leaves the BW room. On leaving she
  comes across a red rose. At that moment she
  learns what its like to see a red rose,
  something she didnt know during her confinement.

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Against Physicalism

• If we accept all that, we have the makings of
  Jacksons argument
• (P1) Physicalism is true (assumption for
  reductio)
• (P2) If Physicalism is true, then (if someone
  knew all of the physical facts, then they would
  know all the facts).
• (P3) At t1 Mary knows all the physical facts.
• (P4) At t1 Mary knows all the facts (from
  (P1)-(P3)).
• (P5) At t2 Mary learns something new she comes
  to know what its like to see a red rose.
• (P6) Coming to know what its like to see a red
  rose is coming to know a fact.
• (C7) Mary didnt know all the facts at t1.
• (C8) Physicalism is false.

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Against Physicalism

• How should the Physicalist respond?

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Against Physicalism

• How should the Physicalist respond?
• There are four main targets
• (P2) If Physicalism is true, then (if someone
  knew all of the physical facts, then they would
  know all the facts).
• One might deny this, e.g. by denying that
  Physicalism entails anything about knowledge.

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Against Physicalism

• (P2) If Physicalism is true, then (if someone
  knew all of the physical facts, then they would
  know all the facts).
• Should we reject this premise?

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Against Physicalism

• How should the Physicalist respond?
• There are four main targets
• (P3) At t1 Mary knows all the physical facts.
• Perhaps one might try to argue that Mary couldnt
  know all the physical facts from her BW room.

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Against Physicalism

• (P3) At t1 Mary knows all the physical facts.
• Should we reject this premise?

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Against Physicalism

• How should the Physicalist respond?
• There are four main targets
• (P5) At t2 Mary learns something new she comes
  to know what its like to see a red rose.
• Perhaps one should reject this. Perhaps Mary
  would be unsurprised by her experience, would
  simply say yes, thats what I though it would be
  like.

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Against Physicalism

• (P5) At t2 Mary learns something new she comes
  to know what its like to see a red rose.
• Should we reject this premise?

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Against Physicalism

• How should the Physicalist respond?
• There are four main targets
• (P6) Coming to know what its like to see a red
  rose is coming to know a fact.
• Perhaps Mary learns something, but this doesnt
  amount to knowledge of a new fact.

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Against Physicalism

• (P6) Coming to know what its like to see a red
  rose is coming to know a fact.
• Should we reject this premise?