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8729
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Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro]
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Full Idea:
Intuitionists in mathematics deny excluded middle, because it is symptomatic of faith in the transcendent existence of mathematical objects and/or the truth of mathematical statements.
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From:
Stewart Shapiro (Thinking About Mathematics [2000], 1.2)
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A reaction:
There are other problems with excluded middle, such as vagueness, but on the whole I, as a card-carrying 'realist', am committed to the law of excluded middle.
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8763
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The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro]
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Full Idea:
It is surely wise to identify the positions in the natural numbers structure with their counterparts in the integer, rational, real and complex number structures.
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From:
Stewart Shapiro (Thinking About Mathematics [2000], 10.2)
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A reaction:
The point is that this might be denied, since 3, 3/1, 3.00.., and -3*i^2 are all arrived at by different methods of construction. Natural 3 has a predecessor, but real 3 doesn't. I agree, intuitively, with Shapiro. Russell (1919) disagreed.
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8762
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Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro]
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Full Idea:
Zermelo said that for each number n, its successor is the singleton of n, so 3 is {{{null}}}, and 1 is not a member of 3. Von Neumann said each number n is the set of numbers less than n, so 3 is {null,{null},{null,{null}}}, and 1 is a member of 3.
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From:
Stewart Shapiro (Thinking About Mathematics [2000], 10.2)
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A reaction:
See Idea 645 - Zermelo could save Plato from the criticisms of Aristotle! These two accounts are cited by opponents of the set-theoretical account of numbers, because it seems impossible to arbitrate between them.
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8749
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Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro]
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Full Idea:
Term Formalism is the view that mathematics is just about characters or symbols - the systems of numerals and other linguistic forms. ...This will cover integers and rational numbers, but what are real numbers supposed to be, if they lack names?
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From:
Stewart Shapiro (Thinking About Mathematics [2000], 6.1.1)
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A reaction:
Real numbers (such as pi and root-2) have infinite decimal expansions, so we can start naming those. We could also start giving names like 'Harry' to other reals, though it might take a while. OK, I give up.
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8750
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Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro]
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Full Idea:
Game Formalism likens mathematics to chess, where the 'content' of mathematics is exhausted by the rules of operating with its language. ...This, however, leaves the problem of why the mathematical games are so useful to the sciences.
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From:
Stewart Shapiro (Thinking About Mathematics [2000], 6.1.2)
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A reaction:
This thought pushes us towards structuralism. It could still be a game, but one we learned from observing nature, which plays its own games. Chess is, after all, modelled on warfare.
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8753
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Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro]
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Full Idea:
Critics commonly complain that the intuitionist restrictions cripple the mathematician. On the other hand, intuitionist mathematics allows for many potentially important distinctions not available in classical mathematics, and is often more subtle.
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From:
Stewart Shapiro (Thinking About Mathematics [2000], 7.1)
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A reaction:
The main way in which it cripples is its restriction on talk of infinity ('Cantor's heaven'), which was resented by Hilbert. Since high-level infinities are interesting, it would be odd if we were not allowed to discuss them.
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8731
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Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro]
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Full Idea:
I classify conceptualists according to what they say about properties or concepts. If someone classified properties as existing independent of language I would classify her as a realist in ontology of mathematics. Or they may be idealists or nominalists.
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From:
Stewart Shapiro (Thinking About Mathematics [2000], 2.2.1)
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A reaction:
In other words, Shapiro wants to eliminate 'conceptualist' as a useful label in philosophy of mathematics. He's probably right. All thought involves concepts, but that doesn't produce a conceptualist theory of, say, football.
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15094
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I now deny that properties are cluster of powers, and take causal properties as basic [Shoemaker]
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Full Idea:
I now reject the formulation of the causal theory which says that a property is a cluster of conditional powers. That has a reductionist flavour, which is a cheat. We need properties to explain conditional powers, so properties won't reduce.
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From:
Sydney Shoemaker (Causal and Metaphysical Necessity [1998], III)
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A reaction:
[compressed wording] I agree with Mumford and Anjum in preferring his earlier formulation. I think properties are broad messy things, whereas powers can be defined more precisely, and seem to have more stability in nature.
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15099
|
If something is possible, but not nomologically possible, we need metaphysical possibility [Shoemaker]
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Full Idea:
If it is possible that there could be possible states of affairs that are not nomologically possible, don't we therefore need a notion of metaphysical possibility that outruns nomological possibility?
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From:
Sydney Shoemaker (Causal and Metaphysical Necessity [1998], VI)
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A reaction:
Shoemaker rejects this possibility (p.425). I sympathise. So there is 'natural' possibility (my preferred term), which is anything which stuff, if it exists, could do, and 'logical' possibility, which is anything that doesn't lead to contradiction.
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15101
|
Once you give up necessity as a priori, causal necessity becomes the main type of necessity [Shoemaker]
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Full Idea:
Once the obstacle of the deeply rooted conviction that necessary truths should be knowable a priori is removed, ...causal necessity is (pretheoretically) the very paradigm of necessity, in ordinary usage and in dictionaries.
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From:
Sydney Shoemaker (Causal and Metaphysical Necessity [1998], VII)
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A reaction:
The a priori route seems to lead to logical necessity, just by doing a priori logic, and also to metaphysical necessity, by some sort of intuitive vision. This is a powerful idea of Shoemaker's (implied, of course, in Kripke).
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15100
|
Imagination reveals conceptual possibility, where descriptions avoid contradiction or incoherence [Shoemaker]
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Full Idea:
Imaginability can give us access to conceptual possibility, when we come to believe situations to be conceptually possible by reflecting on their descriptions and seeing no contradiction or incoherence.
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From:
Sydney Shoemaker (Causal and Metaphysical Necessity [1998], VI)
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A reaction:
If take the absence of contradiction to indicate 'logical' possibility, but the absence of incoherence is more interesting, even if it is a bit vague. He is talking of 'situations', which I take to be features of reality. A priori synthetic?
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16566
|
Poetry is more philosophic than history, as it concerns universals, not particulars [Aristotle]
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Full Idea:
Poetry is something more philosophic and of graver import than history, since its statements are rather of universals, whereas those of history are singulars.
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From:
Aristotle (The Poetics [c.347 BCE], 1451b05)
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A reaction:
Hm. Characters in great novels achieve universality by being representated very particularly. Great depth of mind seems required to be a poet, but less so for a historian (though there is, I presume, no upward limit on the possible level of thought).
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15093
|
We might say laws are necessary by combining causal properties with Armstrong-Dretske-Tooley laws [Shoemaker]
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Full Idea:
One way to get the conclusion that laws are necessary is to combine my view of properties with the view of Armstrong, Dretske and Tooley, that laws are, or assert, relations between properties.
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From:
Sydney Shoemaker (Causal and Metaphysical Necessity [1998], I)
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A reaction:
This is interesting, because Armstrong in particular wants the necessity to arise from relations between properties as universals, but if we define properties causally, and make them necessary, we might get the same result without universals.
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