Monday, March 7, 2011
A.J Ayer – Logical Positivism
Hume – knowledge was twofold: introspection and observation.
Logical positivist – we can only know by observation. [Ex. Teaching a child a term
(cow). Show the child a cow by exposing it to a cow. Child associates ‘cow’ with a cow.]
Terms like electron? Logical positivist – total set of the descriptions of the observable
world that can be confirmed in laboratories, etc. Know the consequences of it being true
that electrons exist, you know electrons exist.
If you know how the world would look for the sentence to be true, then you understand
Can logical positivists make sense of the past?
Statements true by definition – Duncan is a bachelor – it follows that Duncan is
unmarried and a male
Teaching someone a term in terms of other terms you can point at.
Possible experience that the statement can verify if the statement was true
1. Truth/falsity can be told in a brief moment of experience (ex. Sense-data).
Inspecting your own observations
2. Terms of lists of observation sentences (ex. Electron – add up multiple
observations). Theoretical sentences – Empirical meaning
3. Logically determinant (ex. Bachelor) –
Which statements fall into these categories?
Natural sciences, formal sciences do nothing more than work out logical consequences of
Where do philosophical statements lie? Ex. God exists. LP – Define God? Not an
observation term, doesn’t stand for a set of such statements. Can’t define with
experiments you can perform. Statement God exists isn’t true or false – meaningless.
Ex. Picasso’s paintings are beautiful. No test or observation to find out if something is
objectively beautiful – unverifiable, therefore it has no meaning
Ex. It’s work to kill – no empirical property that says it’s wrong to kill.
3 areas of logical discourse LP don’t like: religion, aesthetics, ethics. No concrete evidence of the truth/falsity of sentences
Statements in metaphysics, ontology, epistemology
Problems are grammatical in nature – idealism vs. realism? Experiencing a preference for
a certain vocabulary
More to an object than the sum of its properties
• Ex. Duncan – male, 6’1, brown hair
• Substances (universals)
• Universals only
• What’s the difference? Nothing would be different. Pseudo-problem. Different
way of talking about the same thing
I.e. Redness – no empirical consequences. Either way – still going to be red things. Just a
category choice over which language to choose
LP – formal sciences can derive truth/falsity of statements without observation?
LP – All philosophical problems will collapse or turn into empirical arguments
LP – Operationalize what moral terms meant. Moral statements become empirical, reduce
moral statements to factual statements. LP persuaded by the Open Questi