Combining Texts

All the ideas for 'Frege's Theory of Numbers', 'On the General Idea of Proof Theory' and 'Phenomenology of Perception'

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5 ideas

5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Logical consequence isn't a black box (Tarski's approach); we should explain how arguments work [Prawitz]
     Full Idea: Defining logical consequence in the way Tarski does is a rather meagre result, treating an argument as a black box, observing input and output, while disregarding inner structure. We should define logical consequence on the basis of valid arguments.
     From: Dag Prawitz (On the General Idea of Proof Theory [1974], §2)
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory looks at valid sentences and consequence, but not how we know these things [Prawitz]
     Full Idea: In model theory, which has dominated the last decades, one concentrates on logically valid sentences, and what follows logically from what, but one disregards questions concerning how we know these things.
     From: Dag Prawitz (On the General Idea of Proof Theory [1974], §1)
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
Parsons says counting is tagging as first, second, third..., and converting the last to a cardinal [Parsons,C, by Heck]
     Full Idea: In Parsons's demonstrative model of counting, '1' means the first, and counting says 'the first, the second, the third', where one is supposed to 'tag' each object exactly once, and report how many by converting the last ordinal into a cardinal.
     From: report of Charles Parsons (Frege's Theory of Numbers [1965]) by Richard G. Heck - Cardinality, Counting and Equinumerosity 3
     A reaction: This sounds good. Counting seems to rely on that fact that numbers can be both ordinals and cardinals. You don't 'convert' at the end, though, because all the way you mean 'this cardinality in this order'.
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
Consciousness is based on 'I can', not on 'I think' [Merleau-Ponty]
     Full Idea: Consciousness is in the first place not a matter of 'I think' but of 'I can'.
     From: Maurice Merleau-Ponty (Phenomenology of Perception [1945], p.159), quoted by Beth Lord - Spinoza's Ethics 2 'Sensation'
     A reaction: The point here (quoted during a discussion of Spinoza) is that you can't leave out the role of the body, which seems correct.
12. Knowledge Sources / B. Perception / 5. Interpretation
The mind does not unite perceptions, because they flow into one another [Merleau-Ponty]
     Full Idea: I do not have one perception, then another, and between them a link brought about by the mind. Rather, each perspective merges into the other [against a unified background].
     From: Maurice Merleau-Ponty (Phenomenology of Perception [1945], p.329-30), quoted by Kevin Aho - Existentialism: an introduction 3 'Perceptual'
     A reaction: I take this to be another piece of evidence pointing to realism as the best explanation of experience. A problem for Descartes is what unites the sequence of thoughts.