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13985
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A true proposition seems true of one fact, but a false proposition seems true of nothing at all. [Ryle]
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Full Idea:
Whereas there might be just one fact that a true proposition was like, we would have to say that a false proposition was unlike any fact. We could not speak of the fact that it was false of, so we could not speak of its being false of anything at all.
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From:
Gilbert Ryle (Are there propositions? [1930], 'Objections')
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A reaction:
Ryle brings out very nicely the point Russell emphasised so much, that the most illuminating studies in philosophy are of how falsehood works, rather than of how truths work. If I say 'the Queen is really a man' it is obvious what that is false of.
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8945
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Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher]
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Full Idea:
In fuzzy logic objects have properties to a greater or lesser degree, and truth values are given as fractions or decimals, ranging from 0 to 1. Not-p is defined as 1-p, and other formula are defined in terms of maxima and minima for sets.
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From:
Jennifer Fisher (On the Philosophy of Logic [2008], 07.II)
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A reaction:
The question seems to be whether this is actually logic, or a recasting of probability theory. Susan Haack attacks it. If logic is the study of how truth is preserved as we move between propositions, then 0 and 1 need a special status.
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13979
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Logic studies consequence, compatibility, contradiction, corroboration, necessitation, grounding.... [Ryle]
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Full Idea:
Logic studies the way in which one thing follows from another, in which one thing is compatible with another, contradicts, corroborates or necessitates another, is a special case of another or the nerve of another. And so on.
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From:
Gilbert Ryle (Are there propositions? [1930], IV)
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A reaction:
I presume that 'and so on' would include how one thing proves another. This is quite a nice list, which makes me think a little more widely about the nature of logic (rather than just about inference). Incompatibility isn't a process.
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8951
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Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher]
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Full Idea:
For simplicity, we can say that 'classical logic' amounts to the truth of four sentences: 1) either p or not-p; 2) it is not the case that both p and not-p; 3) from p and not-p, infer q; 4) from p or q and not-p, infer q.
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From:
Jennifer Fisher (On the Philosophy of Logic [2008], 12.I)
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A reaction:
[She says there are many ways of specifying classical logic] Intuition suggests that 2 and 4 are rather hard to dispute, while 1 is ignoring some grey areas, and 3 is totally ridiculous. There is, of course, plenty of support for 3!
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8950
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Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher]
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Full Idea:
Even if one is inclined to be a realist about everything, it is hard to see why our logic should be the determiner. Logic is supposed to formalize how we ought to reason, but whether or not we should be realists is a matter of philosophy, not logic.
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From:
Jennifer Fisher (On the Philosophy of Logic [2008], 09.I)
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A reaction:
Nice to hear a logician saying this. I do not see why talk in terms of an object is a commitment to its existence. We can discuss the philosopher's stone, or Arthur's sword, or the Loch Ness monster, or gravitinos, with degrees of commitment.
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8944
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Vagueness can involve components (like baldness), or not (like boredom) [Fisher]
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Full Idea:
Vague terms come in at least two different kinds: those whose constituent parts come in discrete packets (bald, rich, red) and those that don't (beauty, boredom, niceness).
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From:
Jennifer Fisher (On the Philosophy of Logic [2008], 07.II)
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A reaction:
The first group seem to be features of the external world, and the second all occur in the mind. Baldness may be vague, but presumably hairs are (on the whole) not. Nature doesn't care whether someone is actually 'bald' or not.
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16756
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Substantial forms must exist, to explain the stability of metals like silver and tin [Albertus Magnus]
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Full Idea:
There is no reason why the matter in any natural thing should be stable in its nature, if it is not completed by a substantial form. But we see that silver is stable, and tin and other metals. Therefore they will seem to be perfected by substantial forms.
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From:
Albertus Magnus (On Minerals [1260], III.1.7), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 24.2
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A reaction:
Illuminating. This may be the best reason for proposing substantial forms. Once materialism arrives, the so-called 'laws' of nature have to be imposed on the material to do the job - but what the hell is a law supposed to be?
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13983
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Representation assumes you know the ideas, and the reality, and the relation between the two [Ryle]
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Full Idea:
The theory of Representative Ideas begs the whole question, by assuming a) that we can know these 'Ideas', b) that we can know the realities they represent, and c) we can know a particular 'idea' to be representative of a particular reality.
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From:
Gilbert Ryle (Are there propositions? [1930], 'Objections')
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A reaction:
Personally I regard the ideas as immediate (rather than acquired by some knowledge process), and I am dimly hoping that they represent reality (or I'm in deep trouble), and I am struggling to piece together the reality they represent. I'm happy with that.
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13981
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Several people can believe one thing, or make the same mistake, or share one delusion [Ryle]
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Full Idea:
We ordinarily find no difficulty in saying of a given thing that several people believe it and so, if they think it false, 'make the same mistake' or 'labour under the same delusion'.
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From:
Gilbert Ryle (Are there propositions? [1930], IV)
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A reaction:
Ryle is playing devil's advocate, but this (like 13980) strikes me as quite good support for propositions. I suppose you can describe these phenomena as assent to sentences, but they might be very different sentences to express the same delusion.
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13989
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There are no propositions; they are just sentences, used for thinking, which link to facts in a certain way [Ryle]
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Full Idea:
There are no substantial propositions...There is just a relation between grammatical structure and the logical structure of facts. 'Proposition' denotes the same as 'sentence' or 'statement'. A proposition is not what I think, but what I think or talk in.
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From:
Gilbert Ryle (Are there propositions? [1930], 'Conclusions')
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A reaction:
The conclusion of Ryle's discussion, but I found his support for propositions much more convincing than his critique of them, or his attempt at an alternative linguistic account. He never mentioned animals, so he self-evidently hasn't grasped the problem.
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13982
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If we accept true propositions, it is hard to reject false ones, and even nonsensical ones [Ryle]
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Full Idea:
All the arguments for the subsistence of true propositions seem to hold good for the subsistence of false ones. We might even have to find room for absurd or nonsensical ones like 'some round squares are not red-headed'.
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From:
Gilbert Ryle (Are there propositions? [1930], 'Objections')
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A reaction:
A particularly nice example of a Category Mistake from the man who made them famous. Why can't we just make belief a proposition attitude, so I equally believe 'sea is blue', 'grass is pink' and 'trees are bifocal', but the status of my belief varies?
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