From metaphysics to logical positivism

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From metaphysics to logical positivism

• The metaphysician tells us that empirical
  truth-conditions for metaphysical terms cannot
  be specified if he asserts that nonetheless he
  means something, we show that this is merely an
  allusion to associated words and feelings, which
  however, do not bestow a meaning
• Rudolf Carnap (150)

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Metaphysics to Logical Positivism

• Logical positivism
• empiricist criterion of meaning
• role of philosophy epistemology of science and
  conceptual analyses

• Responses to representative, or causal, realism
  Berkeley (review), Kant
• Response to metaphysics science as antidote

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Idea-ism to Idealism Berkeley

• Recall Berkeleys argument for Idealism
• We perceive such things as trees and stones
• We perceive only ideas and their aggregates
  (Idea-ism)
• Ideas and their aggregates cannot exist
  unperceived
• Therefore, trees and stones are ideas and their
  aggregates, and cannot exist unperceived
  (Idealism)

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Berkeleys Idealism

• For Berkeley, all properties are secondary that
  is there are no mind-independent ( primary)
  properties
• Idealism is a metaphysical thesis that all that
  exist is mental in nature, hence it is
  incompatible with any form of metaphysical
  realism (144).

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Kantian alternative

• Kant agrees with metaphysical realism there is a
  mind-independent world
• However, we dont know anything about it
  (noumenal world)
• Our knowledge is of the world as it is for us
  the phenomenal world (141)

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Metaphysics to Logical Positivism

• If you were a scientifically-minded philosopher,
  what to make of the arguments by Berkeley and
  Kant?
• Of course we should believe in a mind-independent
  world and we can know that world.
• How do we argue for that conclusion?
• That such a world exists is the inference to the
  best possible explanation of all the evidence we
  have

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Positivism

• Logical positivism has its roots in Auguste
  Comtes (1798-1857) positivist philosophy
• The positivist movement is a backlash against
  the dominance of metaphysics in 19th Century
  philosophy
• Think about Hegels concept of Spirit or
  Absolute knowing

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Positivism

• Comte claims that societies pass through three
  stages
• Theological appeal to deities to explain the
  nature of things in themselves
• Metaphysical appeal to unknown forces to explain
  the nature of things in themselves
• Scientific renounces pretense to know the nature
  of things in themselves science should stick to
  predictions.

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Positivism

• Comtes positivism emphasizes
• Empiricism
• Renounce the pretension to know the nature of
  things in themselves
• 1) anti-theoretical entities
• 2) anti-metaphysics (in general)

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Logical Positivism

• Logical positivism emerged in the 1920s.
• For logical positivists, the antidote to
  metaphysical talk logic, mathematics and science
• Mathematical logic provides the framework in
  which theories can be precisely formulated

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Logical Positivism

• For logical positivists, if the connections
  between ideas and associated experience could be
  made precise then it would be possible to
  separate meaningless metaphysical talk from
  empirical science (Ladyman 149)
• Assumption words get their meanings by
  connection to experience
• Implication no matter of fact can be
  intelligibly thought about can go beyond all
  possible sense experience (Ladyman 150)

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Logical Positivism

• Empiricist criterion of meaning to be
  meaningful a word must have some connection with
  what can be experienced (ibid).
• Contrast thing-in-itself with microwave

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Logical positivismempiricist criterion of meaning

• Empiricist criterion of meaning used to demarcate
  between science and pseudo-science
  pseudo-science uses meaningless concepts.
• By the empiricist criterion of meaning, claims
  made in theology are meaningless.
• By that criterion, claims in ethics mean
  something different than what we think.

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Summary of logical positivist commitments (157)

1. Science is the only intellectually respectable
   form of inquiry
2. All truths are either analytic a priori or
   synthetic a posteriori
3. Philosophy explains the structure, or logic, of
   science. The role of philosophy is the
   epistemology of science and conceptual analyses

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Summary of logical positivist commitments (157)

• Logic expresses precisely the relation between
  concepts
• Verifiability criterion of meaning a statement
  is literally meaningful if and only if it is
  either analytically or empirically verifiable
• Verification principle the meaning of a
  non-tautological statement is its method of
  verification that is the way in which it can
  shown to be true

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Positivist epistemology

• Positivists hold that our knowledge is built up
  from basic beliefs which are self-evidently true
  (i.e. immune from doubt)
• All other beliefs are justified either
  deductively or inductively from basic beliefs
• This view is called FOUNDATIONALISM

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Positivist epistemology

• Basic beliefs are called protocol statements.
• Protocol statements first person, singular,
  present tense, introspective reports (152).
• Heres an example I seem to sense a patch of
  red in my visual field.

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Positivist epistemology

• Why is this claim immune from doubt?
• Even if I am wrong about the object I see, I
  cant doubt that it appears that I am sensing a
  patch of red in my visual field

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Logical positivist epistemology

• I seem to sense a patch of red in my visual
  field.
• Is strongly verified because it simply reports
  ones sense experience
• Weakly verifies other non-basic statements, or
  empirical hypotheses, I see a red ball in the
  corner.
• Why do protocol statements only weakly justifies
  these other statements?

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Dilemma for logical positivism

• We (claim to) know lots about the world
• We only know protocol statements and analytic
  truth
• To avoid skepticism about the external world,
  logical positivists need to infer (1) from (2).
• What kind of argument can they use? Deductive?
  Inductive?

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Solution to dilemma

• Solution Proposition asserting the existence of
  physical objects are equivalent to ones asserting
  that the observer will have certain sequence of
  sensations in certain circumstances (Ladyman
  153).

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Logical positivism phenomenalism

• Talk of perceived or possible objects is
  reducible to talk of actual or possible
  experience.
• Physical objects are permanent possibility of
  sensation they are logical constructions out
  of actual and possible sense experience (ibid).
• This position is called PHENOMENALISM

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Logical positivism

• With logical positivism, physical objects are
  permanent possibility of sensation they are
  logical constructions out of actual and possible
  experience
• This move, though seemingly counter intuitive,
  has the virtue of doing away with metaphysical
  debates. Why?

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Logical positivism

• For the logical positivists, the table of
  commonsense, is a mere construction from
  sense-data.
• What about the scientific table, the table of
  atoms, electrons, etc?
• Is the scientific table also a mere
  construction from sense-data?
• Do we have such sense-data?