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Ideas for 'fragments/reports', 'Review of Chihara 'Struct. Accnt of Maths'' and 'An Inquiry into Meaning and Truth'

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5 ideas

5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / e. or
Disjunction may also arise in practice if there is imperfect memory. [Russell]
     Full Idea: Another situation in which a disjunction may arise is practice is imperfect memory. 'Either Brown or Jones told me that'.
     From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5)
A disjunction expresses indecision [Russell]
     Full Idea: A disjunction is the verbal expression of indecision, or, if a question, of the desire to reach a decision.
     From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5)
     A reaction: Russell is fishing here for Grice's conversational implicature. If you want to assert a simple proposition, you don't introduce it into an irrelevant disjunction, because that would have a particular expressive purpose.
'Or' expresses hesitation, in a dog at a crossroads, or birds risking grabbing crumbs [Russell]
     Full Idea: Psychologically, 'or' corresponds to a state of hesitation. A dog waits at a fork in the road, to see which way you are going. For crumbs on a windowsill, birds behave in a manner we would express by 'shall I be brave, or go hungry?'.
     From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5)
     A reaction: I love two facts here - first, that Russell wants to link the connective to the psychology of experience, and second, that a great logician wants to connect his logic to the minds of animals.
'Or' expresses a mental state, not something about the world [Russell]
     Full Idea: When we assert 'p or q' we are in a state which is derivative from two previous states, and we express this state, not something about the world.
     From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5)
     A reaction: His example: at a junction this road or that road goes to Oxford, but the world only contains the roads, not some state of 'this or that road'. He doesn't deny that in one sense 'p or q' tells you something about the world.
Maybe the 'or' used to describe mental states is not the 'or' of logic [Russell]
     Full Idea: It might be contended that, in describing what happens when a man believes 'p or q', the 'or' that we must use is not the same as the 'or' of logic.
     From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5)
     A reaction: This seems to be the general verdict on Russell's enquiries in this chapter, but I love any attempt, however lacking in rigour etc., to connect formal logic to how we think, and thence to the world.