Combining Texts

All the ideas for 'Classical Cosmology (frags)', 'A Materialist Theory of Mind (Rev)' and 'Mathematical logic and theory of types'

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15 ideas

4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory
Classes can be reduced to propositional functions [Russell, by Hanna]
     Full Idea: Russell held that classes can be reduced to propositional functions.
     From: report of Bertrand Russell (Mathematical logic and theory of types [1908]) by Robert Hanna - Rationality and Logic 2.4
     A reaction: The exact nature of a propositional function is disputed amongst Russell scholars (though it is roughly an open sentence of the form 'x is red').
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / d. Russell's paradox
The class of classes which lack self-membership leads to a contradiction [Russell, by Grayling]
     Full Idea: The class of teaspoons isn't a teaspoon, so isn't a member of itself; but the class of non-teaspoons is a member of itself. The class of all classes which are not members of themselves is a member of itself if it isn't a member of itself! Paradox.
     From: report of Bertrand Russell (Mathematical logic and theory of types [1908]) by A.C. Grayling - Russell Ch.2
     A reaction: A very compressed version of Russell's famous paradox, often known as the 'barber' paradox. Russell developed his Theory of Types in an attempt to counter the paradox. Frege's response was to despair of his own theory.
6. Mathematics / C. Sources of Mathematics / 6. Logicism / b. Type theory
Type theory seems an extreme reaction, since self-exemplification is often innocuous [Swoyer on Russell]
     Full Idea: Russell's reaction to his paradox (by creating his theory of types) seems extreme, because many cases of self-exemplification are innocuous. The property of being a property is itself a property.
     From: comment on Bertrand Russell (Mathematical logic and theory of types [1908]) by Chris Swoyer - Properties 7.5
     A reaction: Perhaps it is not enough that 'many cases' are innocuous. We are starting from philosophy of mathematics, where precision is essentially. General views about properties come later.
Russell's improvements blocked mathematics as well as paradoxes, and needed further axioms [Russell, by Musgrave]
     Full Idea: Unfortunately, Russell's new logic, as well as preventing the deduction of paradoxes, also prevented the deduction of mathematics, so he supplemented it with additional axioms, of Infinity, of Choice, and of Reducibility.
     From: report of Bertrand Russell (Mathematical logic and theory of types [1908]) by Alan Musgrave - Logicism Revisited §2
     A reaction: The first axiom seems to be an empirical hypothesis, and the second has turned out to be independent of logic and set theory.
Type theory means that features shared by different levels cannot be expressed [Morris,M on Russell]
     Full Idea: Russell's theory of types avoided the paradoxes, but it had the result that features common to different levels of the hierarchy become uncapturable (since any attempt to capture them would involve a predicate which disobeyed the hierarchy restrictions).
     From: comment on Bertrand Russell (Mathematical logic and theory of types [1908]) by Michael Morris - Guidebook to Wittgenstein's Tractatus 2H
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
Ramified types can be defended as a system of intensional logic, with a 'no class' view of sets [Russell, by Linsky,B]
     Full Idea: A defence of the ramified theory of types comes in seeing it as a system of intensional logic which includes the 'no class' account of sets, and indeed the whole development of mathematics, as just a part.
     From: report of Bertrand Russell (Mathematical logic and theory of types [1908]) by Bernard Linsky - Russell's Metaphysical Logic 6.1
     A reaction: So Linsky's basic project is to save logicism, by resting on intensional logic (rather than extensional logic and set theory). I'm not aware that Linsky has acquired followers for this. Maybe Crispin Wright has commented?
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
A set does not exist unless at least one of its specifications is predicative [Russell, by Bostock]
     Full Idea: The idea is that the same set may well have different canonical specifications, i.e. there may be different ways of stating its membership conditions, and so long as one of these is predicative all is well. If none are, the supposed set does not exist.
     From: report of Bertrand Russell (Mathematical logic and theory of types [1908]) by David Bostock - Philosophy of Mathematics 8.1
Russell is a conceptualist here, saying some abstracta only exist because definitions create them [Russell, by Bostock]
     Full Idea: It is a conceptualist approach that Russell is relying on. ...The view is that some abstract objects ...exist only because they are definable. It is the definition that would (if permitted) somehow bring them into existence.
     From: report of Bertrand Russell (Mathematical logic and theory of types [1908]) by David Bostock - Philosophy of Mathematics 8.1
     A reaction: I'm suddenly thinking that predicativism is rather interesting. Being of an anti-platonist persuasion about abstract 'objects', I take some story about how we generate them to be needed. Psychological abstraction seems right, but a bit vague.
Vicious Circle says if it is expressed using the whole collection, it can't be in the collection [Russell, by Bostock]
     Full Idea: The Vicious Circle Principle says, roughly, that whatever involves, or presupposes, or is only definable in terms of, all of a collection cannot itself be one of the collection.
     From: report of Bertrand Russell (Mathematical logic and theory of types [1908], p.63,75) by David Bostock - Philosophy of Mathematics 8.1
     A reaction: This is Bostock's paraphrase of Russell, because Russell never quite puts it clearly. The response is the requirement to be 'predicative'. Bostock emphasises that it mainly concerns definitions. The Principle 'always leads to hierarchies'.
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / a. Dispositions
To be realists about dispositions, we can only discuss them through their categorical basis [Armstrong]
     Full Idea: It is only to the extent that we relate disposition to 'categorical basis', and difference of disposition to difference of 'categorical basis', that we can speak of dispositions. We must be Realists, not Phenomenalists, about dispositions.
     From: David M. Armstrong (A Materialist Theory of Mind (Rev) [1968], 6.VI)
     A reaction: It is Armstrong's realism which motivates this claim, because he thinks only categorical properties are real. But categorical properties seem to be passive, and the world is active.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / d. Secondary qualities
Armstrong suggests secondary qualities are blurred primary qualities [Armstrong, by Robinson,H]
     Full Idea: According to D.M. Armstrong and others, when we perceive secondary qualities we are in fact perceiving primary qualities in a confused, indistinct or blurred way.
     From: report of David M. Armstrong (A Materialist Theory of Mind (Rev) [1968], 270-90) by Howard Robinson - Perception III.1
     A reaction: This is obviously an attempt to fit secondary qualities into a reductive physicalist account of the mind. Personally I favour Armstrong's project, but doubt whether this strategy is necessary. I just don't think there is anything 'primary' about redness.
16. Persons / C. Self-Awareness / 1. Introspection
A mental state without belief refutes self-intimation; a belief with no state refutes infallibility [Armstrong, by Shoemaker]
     Full Idea: For Armstrong, introspection involves a belief, and mental states and their accompanying beliefs are 'distinct existences', so a state without belief shows states are not self-intimating, and the belief without the state shows beliefs aren't infallible.
     From: report of David M. Armstrong (A Materialist Theory of Mind (Rev) [1968]) by Sydney Shoemaker - Introspection
     A reaction: I agree with Armstrong. Introspection is a two-level activity, which animals probably can't do, and there is always the possibility of a mismatch between the two levels, so introspection is neither self-intimating nor infallibe (though incorrigible).
17. Mind and Body / C. Functionalism / 4. Causal Functionalism
If pains are defined causally, and research shows that the causal role is physical, then pains are physical [Armstrong, by Lycan]
     Full Idea: Armstrong and Lewis said that mental items were defined in terms of typical causes and effects; if, as seems likely, research reveals that a particular causal niche is occupied by a physical state, it follows that pain is a physical state.
     From: report of David M. Armstrong (A Materialist Theory of Mind (Rev) [1968]) by William Lycan - Introduction - Ontology p.5
     A reaction: I am not fully convinced of the first step in the argument. It sounds like the epistemology and the ontology have got muddled (as usual). We define mental states as we define electrons, in terms of observed behaviour, but what are they?
Armstrong and Lewis see functionalism as an identity of the function and its realiser [Armstrong, by Heil]
     Full Idea: The Armstrong/Lewis version of functionalism takes mental properties to be functional properties, but identifies these with what other functionalists would regard as their realisers.
     From: report of David M. Armstrong (A Materialist Theory of Mind (Rev) [1968]) by John Heil - Philosophy of Mind Ch.4
     A reaction: Heil rejects this, but I am beginning to think that this is the answer. If functions do not have an ontological life of their own (the 'ringing' of the bell), then functionalist mental states can't either. Function is not an ontological category.
27. Natural Reality / E. Cosmology / 1. Cosmology
Is the cosmos open or closed, mechanical or teleological, alive or inanimate, and created or eternal? [Robinson,TM, by PG]
     Full Idea: The four major disputes in classical cosmology were whether the cosmos is 'open' or 'closed', whether it is explained mechanistically or teleologically, whether it is alive or mere matter, and whether or not it has a beginning.
     From: report of T.M. Robinson (Classical Cosmology (frags) [1997]) by PG - Db (ideas)
     A reaction: A nice summary. The standard modern view is closed, mechanistic, inanimate and non-eternal. But philosophers can ask deeper questions than physicists, and I say we are entitled to speculate when the evidence runs out.