Combining Texts

All the ideas for 'Logical Pluralism', 'Reference and Generality (3rd ed)' and 'Review of Aron 'Our Knowledge of Universals''

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31 ideas

3. Truth / A. Truth Problems / 1. Truth
Some truths have true negations [Beall/Restall]
     Full Idea: Dialetheism is the view that some truths have true negations.
     From: JC Beall / G Restall (Logical Pluralism [2006], 7.4)
     A reaction: The important thing to remember is that they are truths. Thus 'Are you feeling happy?' might be answered 'Yes and no'.
3. Truth / B. Truthmakers / 5. What Makes Truths / b. Objects make truths
A truthmaker is an object which entails a sentence [Beall/Restall]
     Full Idea: The truthmaker thesis is that an object is a truthmaker for a sentence if and only if its existence entails the sentence.
     From: JC Beall / G Restall (Logical Pluralism [2006], 5.5.3)
     A reaction: The use of the word 'object' here is even odder than usual, and invites many questions. And the 'only if' seems peculiar, since all sorts of things can make a sentence true. 'There is someone in the house' for example.
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
(∀x)(A v B) |- (∀x)A v (∃x)B) is valid in classical logic but invalid intuitionistically [Beall/Restall]
     Full Idea: The inference of 'distribution' (∀x)(A v B) |- (∀x)A v (∃x)B) is valid in classical logic but invalid intuitionistically. It is straightforward to construct a 'stage' at which the LHS is true but the RHS is not.
     From: JC Beall / G Restall (Logical Pluralism [2006], 6.1.2)
     A reaction: This seems to parallel the iterative notion in set theory, that you must construct your hierarchy. All part of the general 'constructivist' approach to things. Is some kind of mad platonism the only alternative?
4. Formal Logic / E. Nonclassical Logics / 5. Relevant Logic
Excluded middle must be true for some situation, not for all situations [Beall/Restall]
     Full Idea: Relevant logic endorses excluded middle, ..but says instances of the law may fail. Bv¬B is true in every situation that settles the matter of B. It is necessary that there is some such situation.
     From: JC Beall / G Restall (Logical Pluralism [2006], 5.2)
     A reaction: See next idea for the unusual view of necessity on which this rests. It seems easier to assert something about all situations than just about 'some' situation.
It's 'relevantly' valid if all those situations make it true [Beall/Restall]
     Full Idea: The argument from P to A is 'relevantly' valid if and only if, for every situation in which each premise in P is true, so is A.
     From: JC Beall / G Restall (Logical Pluralism [2006], 5.2)
     A reaction: I like the idea that proper inference should have an element of relevance to it. A falsehood may allow all sorts of things, without actually implying them. 'Situations' sound promising here.
Relevant logic does not abandon classical logic [Beall/Restall]
     Full Idea: We have not abandoned classical logic in our acceptance of relevant logic.
     From: JC Beall / G Restall (Logical Pluralism [2006], 5.4)
     A reaction: It appears that classical logic is straightforwardly accepted, but there is a difference of opinion over when it is applicable.
Relevant consequence says invalidity is the conclusion not being 'in' the premises [Beall/Restall]
     Full Idea: Relevant consequence says the conclusion of a relevantly invalid argument is not 'carried in' the premises - it does not follow from the premises.
     From: JC Beall / G Restall (Logical Pluralism [2006], 5.3.3)
     A reaction: I find this appealing. It need not invalidate classical logic. It is just a tougher criterion which is introduced when you want to do 'proper' reasoning, instead of just playing games with formal systems.
A doesn't imply A - that would be circular [Beall/Restall]
     Full Idea: We could reject the inference from A to itself (on grounds of circularity).
     From: JC Beall / G Restall (Logical Pluralism [2006], 8)
     A reaction: [Martin-Meyer System] 'It's raining today'. 'Are you implying that it is raining today?' 'No, I'm SAYING it's raining today'. Logicians don't seem to understand the word 'implication'. Logic should capture how we reason. Nice proposal.
Relevant logic may reject transitivity [Beall/Restall]
     Full Idea: Some relevant logics reject transitivity, but we defend the classical view.
     From: JC Beall / G Restall (Logical Pluralism [2006], 8)
     A reaction: [they cite Neil Tennant for this view] To reject transitivity (A?B ? B?C ? A?C) certainly seems a long way from classical logic. But in everyday inference Tennant's idea seems good. The first premise may be irrelevant to the final conclusion.
4. Formal Logic / E. Nonclassical Logics / 6. Free Logic
Free logic terms aren't existential; classical is non-empty, with referring names [Beall/Restall]
     Full Idea: A logic is 'free' to the degree it refrains from existential import of its singular and general terms. Classical logic must have non-empty domain, and each name must denote in the domain.
     From: JC Beall / G Restall (Logical Pluralism [2006], 7.1)
     A reaction: My intuition is that logic should have no ontology at all, so I like the sound of 'free' logic. We can't say 'Pegasus does not exist', and then reason about Pegasus just like any other horse.
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Logic studies consequence; logical truths are consequences of everything, or nothing [Beall/Restall]
     Full Idea: Nowadays we think of the consequence relation itself as the primary subject of logic, and view logical truths as degenerate instances of this relation. Logical truths follow from any set of assumptions, or from no assumptions at all.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.2)
     A reaction: This seems exactly right; the alternative is the study of necessities, but that may not involve logic.
Syllogisms are only logic when they use variables, and not concrete terms [Beall/Restall]
     Full Idea: According to the Peripatetics (Aristotelians), only syllogistic laws stated in variables belong to logic, and not their applications to concrete terms.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.5)
     A reaction: [from Lukasiewicz] Seems wrong. I take it there are logical relations between concrete things, and the variables are merely used to describe these relations. Variables lack the internal powers to drive logical necessities. Variables lack essence!
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
The view of logic as knowing a body of truths looks out-of-date [Beall/Restall]
     Full Idea: Through much of the 20th century the conception of logic was inherited from Frege and Russell, as knowledge of a body of logical truths, as arithmetic or geometry was a knowledge of truths. This is odd, and a historical anomaly.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.2)
     A reaction: Interesting. I have always taken this idea to be false. I presume logic has minimal subject matter and truths, and preferably none at all.
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
Logic studies arguments, not formal languages; this involves interpretations [Beall/Restall]
     Full Idea: Logic does not study formal languages for their own sake, which is formal grammar. Logic evaluates arguments, and primarily considers formal languages as interpreted.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.1)
     A reaction: Hodges seems to think logic just studies formal languages. The current idea strikes me as a much more sensible view.
5. Theory of Logic / A. Overview of Logic / 8. Logic of Mathematics
The model theory of classical predicate logic is mathematics [Beall/Restall]
     Full Idea: The model theory of classical predicate logic is mathematics if anything is.
     From: JC Beall / G Restall (Logical Pluralism [2006], 4.2.1)
     A reaction: This is an interesting contrast to the claim of logicism, that mathematics reduces to logic. This idea explains why students of logic are surprised to find themselves involved in mathematics.
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
There are several different consequence relations [Beall/Restall]
     Full Idea: We are pluralists about logical consequence because we take there to be a number of different consequence relations, each reflecting different precisifications of the pre-theoretic notion of deductive logical consequence.
     From: JC Beall / G Restall (Logical Pluralism [2006], 8)
     A reaction: I don't see how you avoid the slippery slope that leads to daft logical rules like Prior's 'tonk' (from which you can infer anything you like). I say that nature imposes logical conquence on us - but don't ask me to prove it.
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
A sentence follows from others if they always model it [Beall/Restall]
     Full Idea: The sentence X follows logically from the sentences of the class K if and only if every model of the class K is also a model of the sentence X.
     From: JC Beall / G Restall (Logical Pluralism [2006], 3.2)
     A reaction: This why the symbol |= is often referred to as 'models'.
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Logical truth is much more important if mathematics rests on it, as logicism claims [Beall/Restall]
     Full Idea: If mathematical truth reduces to logical truth then it is important what counts as logically true, …but if logicism is not a going concern, then the body of purely logical truths will be less interesting.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.2)
     A reaction: Logicism would only be one motivation for pursuing logical truths. Maybe my new 'Necessitism' will derive the Peano Axioms from broad necessary truths, rather than from logic.
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / d. The Preface paradox
Preface Paradox affirms and denies the conjunction of propositions in the book [Beall/Restall]
     Full Idea: The Paradox of the Preface is an apology, that you are committed to each proposition in the book, but admit that collectively they probably contain a mistake. There is a contradiction, of affirming and denying the conjunction of propositions.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.4)
     A reaction: This seems similar to the Lottery Paradox - its inverse perhaps. Affirm all and then deny one, or deny all and then affirm one?
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / d. Counting via concepts
Are 'word token' and 'word type' different sorts of countable objects, or two ways of counting? [Geach, by Perry]
     Full Idea: If we list the words 'bull', 'bull' and 'cow', it is often said that there are three 'word tokens' but only two 'word types', but Geach says there are not two kinds of object to be counted, but two different ways of counting the same object.
     From: report of Peter Geach (Reference and Generality (3rd ed) [1980]) by John Perry - The Same F II
     A reaction: Insofar as the notion that a 'word type' is an 'object', my sympathies are entirely with Geach, to my surprise. Geach's point is that 'bull' and 'bull' are the same meaning, but different actual words. Identity is relative to a concept.
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
We should abandon absolute identity, confining it to within some category [Geach, by Hawthorne]
     Full Idea: Geach argued that the notion of absolute identity should be abandoned. ..We can only grasp the meaning of a count noun when we associate it with a criterion of identity, expressed by a particular relative identity sortal.
     From: report of Peter Geach (Reference and Generality (3rd ed) [1980]) by John Hawthorne - Identity
     A reaction: In other words, identity needs categorisation. Hawthorne concludes that Geach is wrong. Geach clearly has much common usage on his side. 'What's that?' usually invites a categorisation. Sameness of objects seems to need a 'respect'.
9. Objects / F. Identity among Objects / 3. Relative Identity
Denial of absolute identity has drastic implications for logic, semantics and set theory [Wasserman on Geach]
     Full Idea: Geach's denial of absolute identity has drastic implications for logic, semantics and set theory. He must deny the axiom of extensionality in set theory, for example.
     From: comment on Peter Geach (Reference and Generality (3rd ed) [1980]) by Ryan Wasserman - Material Constitution 6
     A reaction: I'm beginning to think we have two entirely different concepts here - the logicians' and mathematicians' notion of when two things are identical, and the ordinary language concept of two things being 'the same'. 'We like the same music'.
Identity is relative. One must not say things are 'the same', but 'the same A as' [Geach]
     Full Idea: Identity is relative. When one says 'x is identical with y' this is an incomplete expression. It is short for 'x is the same A as y', where 'A' represents some count noun understood from the context of utterance.
     From: Peter Geach (Reference and Generality (3rd ed) [1980], p.39), quoted by John Perry - The Same F I
     A reaction: Perry notes that Geach's view is in conscious opposition to Frege, who had a pure notion of identity. We say 'they are the same insofar as they are animals', but not 'they are the same animal'. Perfect identity involves all possible A's.
9. Objects / F. Identity among Objects / 8. Leibniz's Law
Leibniz's Law is incomplete, since it includes a non-relativized identity predicate [Geach, by Wasserman]
     Full Idea: Geach rejects the standard formulation of Leibniz's Law as incomplete, since it includes a non-relativized identity predicate.
     From: report of Peter Geach (Reference and Generality (3rd ed) [1980]) by Ryan Wasserman - Material Constitution 6
     A reaction: Not many people accept Geach's premiss that identity is a relative matter. I agree with Wiggins on this, that identity is an absolute (and possibly indefinable). The problem with the Law is what you mean by a 'property'.
10. Modality / A. Necessity / 3. Types of Necessity
Relevant necessity is always true for some situation (not all situations) [Beall/Restall]
     Full Idea: In relevant logic, the necessary truths are not those which are true in every situation; rather, they are those for which it is necessary that there is a situation making them true.
     From: JC Beall / G Restall (Logical Pluralism [2006], 5.2)
     A reaction: This seems to rest on the truthmaker view of such things, which I find quite attractive (despite Merricks's assault). Always ask what is making some truth necessary. This leads you to essences.
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
Judgement is always predicating a property of a subject [Beall/Restall]
     Full Idea: All judgement, for Kant, is essentially the predication of some property to some subject.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.5)
     A reaction: Presumably the denial of a predicate could be a judgement, or the affirmation of ambiguous predicates?
18. Thought / D. Concepts / 2. Origin of Concepts / a. Origin of concepts
We reach concepts by clarification, or by definition, or by habitual experience [Price,HH]
     Full Idea: We have three different ways in which we arrive at concepts or universals: there is a clarification, where we have a ready-made concept and define it; we have a combination (where a definition creates a concept); and an experience can lead to a habit.
     From: H.H. Price (Review of Aron 'Our Knowledge of Universals' [1946], p.190)
     A reaction: [very compressed] He cites Russell as calling the third one a 'condensed induction'. There seems to an intellectualist and non-intellectualist strand in the abstractionist tradition.
18. Thought / E. Abstraction / 2. Abstracta by Selection
A 'felt familiarity' with universals is more primitive than abstraction [Price,HH]
     Full Idea: A 'felt familiarity' with universals seems to be more primitive than explicit abstraction.
     From: H.H. Price (Review of Aron 'Our Knowledge of Universals' [1946], p.188)
     A reaction: This I take to be part of the 'given' of the abstractionist view, which is quite well described in the first instance by Aristotle. Price says that it is 'pre-verbal'.
Our understanding of 'dog' or 'house' arises from a repeated experience of concomitances [Price,HH]
     Full Idea: Whether you call it inductive or not, our understanding of such a word as 'dog' or 'house' does arise from a repeated experience of concomitances.
     From: H.H. Price (Review of Aron 'Our Knowledge of Universals' [1946], p.191)
     A reaction: Philosophers don't use phrases like that last one any more. How else could we form the concept of 'dog' - if we are actually allowed to discuss the question of concept-formation, instead of just the logic of concepts.
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
We can rest truth-conditions on situations, rather than on possible worlds [Beall/Restall]
     Full Idea: Situation semantics is a variation of the truth-conditional approach, taking the salient unit of analysis not to be the possible world, or some complete consistent index, but rather the more modest 'situation'.
     From: JC Beall / G Restall (Logical Pluralism [2006], 5.5.4)
     A reaction: When I read Davidson (and implicitly Frege) this is what I always assumed was meant. The idea that worlds are meant has crept in to give truth conditions for modal statements. Hence situation semantics must cover modality.
19. Language / D. Propositions / 1. Propositions
Propositions commit to content, and not to any way of spelling it out [Beall/Restall]
     Full Idea: Our talk of propositions expresses commitment to the general notion of content, without a commitment to any particular way of spelling this out.
     From: JC Beall / G Restall (Logical Pluralism [2006], 2.1)
     A reaction: As a fan of propositions I like this. It leaves open the question of whether the content belongs to the mind or the language. Animals entertain propositions, say I.