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Ideas for 'fragments/reports', 'The Principles of Mathematics' and 'The Pragmatist Account of Truth'

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5 ideas

2. Reason / B. Laws of Thought / 3. Non-Contradiction
Man has an intense natural interest in the consistency of his own thinking [James]
     Full Idea: After man's interest in breathing freely, the greatest of all his interests (because it never fluctuates or remits….) is his interest in consistency, in feeling that what he now thinks goes with what he thinks on other occasions.
     From: William James (The Pragmatist Account of Truth [1908], 'Seventh')
     A reaction: People notoriously contradict themselves all the time, but I suspect that it is when they get out of their depth in complexities such as politics. They probably achieve great consistency within their own expertise, and in common knowledge.
2. Reason / D. Definition / 13. Against Definition
Definition by analysis into constituents is useless, because it neglects the whole [Russell]
     Full Idea: A definition as an analysis of an idea into its constituents is inconvenient and, I think, useless; it overlooks the fact that wholes are not, as a rule, determinate when their constituents are given.
     From: Bertrand Russell (The Principles of Mathematics [1903], §108)
     A reaction: The influence of Leibniz seems rather strong here, since he was obsessed with explaining what creates true unities.
In mathematics definitions are superfluous, as they name classes, and it all reduces to primitives [Russell]
     Full Idea: The statement that a class is to be represented by a symbol is a definition in mathematics, and says nothing about mathematical entities. Any formula can be stated in terms of primitive ideas, so the definitions are superfluous.
     From: Bertrand Russell (The Principles of Mathematics [1903], §412)
     A reaction: [compressed wording] I'm not sure that everyone would agree with this (e.g. Kit Fine), as certain types of numbers seem to be introduced by stipulative definitions.
2. Reason / F. Fallacies / 2. Infinite Regress
Infinite regresses have propositions made of propositions etc, with the key term reappearing [Russell]
     Full Idea: In the objectionable kind of infinite regress, some propositions join to constitute the meaning of some proposition, but one of them is similarly compounded, and so ad infinitum. This comes from circular definitions, where the term defined reappears.
     From: Bertrand Russell (The Principles of Mathematics [1903], §329)
2. Reason / F. Fallacies / 8. Category Mistake / a. Category mistakes
As well as a truth value, propositions have a range of significance for their variables [Russell]
     Full Idea: Every proposition function …has, in addition to its range of truth, a range of significance, i.e. a range within which x must lie if φ(x) is to be a proposition at all, whether true or false. This is the first point of the theory of types.
     From: Bertrand Russell (The Principles of Mathematics [1903], App B:523), quoted by Ofra Magidor - Category Mistakes 1.2
     A reaction: Magidor quotes this as the origin of the idea of a 'category mistake'. It is the basis of the formal theory of types, but is highly influential in philosophy generally, especially as a criterion for ruling many propositions as 'meaningless'.