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All the ideas for '', 'The Nature of Thought' and 'Intellectual Autobiography'

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15 ideas

2. Reason / A. Nature of Reason / 6. Coherence
2764 Full coherence might involve consistency and mutual entailment of all propositions [Blanshard, by Dancy,J]
     Full Idea: Blanshard says that in a fully coherent system there would not only be consistency, but every proposition would be entailed by the others, and no proposition would stand outside the system.
     From: report of Brand Blanshard (The Nature of Thought [1939], 2:265) by Jonathan Dancy - Intro to Contemporary Epistemology 8.1
     A reaction: Hm. If a proposition is entailed by the others, then it is a necessary truth (given the others) which sounds deterministic. You could predict all the truths you had never encountered. See 1578:178 for quote.
3. Truth / B. Truthmakers / 5. What Makes Truths / a. What makes truths
18901 Truthmakers are facts 'of' a domain, not something 'in' the domain [Sommers]
     Full Idea: A fact is an existential characteristic 'of' the domain; it is not something 'in' the domain. To search for truth-making facts in the world is indeed futile.
     From: Fred Sommers (Intellectual Autobiography [2005], 'Existence')
     A reaction: Attacking Austin on truth. Helpful. It is hard to see how a physical object has a mysterious power to 'make' a truth. No energy-transfer seems involved in the making. Animals think true thoughts; I suspect that concerns their mental maps of the world.
3. Truth / D. Coherence Truth / 1. Coherence Truth
19080 Coherence tests for truth without implying correspondence, so truth is not correspondence [Blanshard, by Young,JO]
     Full Idea: Blanshard said that coherent justification leads to coherence truth. It might be said that coherence is a test for truth, but truth is correspondence. But coherence doesn't guarantee correspondence, and coherence is a test, so truth is not correspondence.
     From: report of Brand Blanshard (The Nature of Thought [1939], Ch.26) by James O. Young - The Coherence Theory of Truth §2.2
     A reaction: [compression of Young's summary] Rescher (1973) says that Blanshard's argument depends on coherence being an infallible test for truth, which it isn't.
4. Formal Logic / A. Syllogistic Logic / 3. Term Logic
18904 'Predicable' terms come in charged pairs, with one the negation of the other [Sommers, by Engelbretsen]
     Full Idea: Sommers took the 'predicable' terms of any language to come in logically charged pairs. Examples might be red/nonred, massive/massless, tied/untied, in the house/not in the house. The idea that terms can be negated was essential for such pairing.
     From: report of Fred Sommers (Intellectual Autobiography [2005]) by George Engelbretsen - Trees, Terms and Truth 2
     A reaction: If, as Rumfitt says, we learn affirmation and negation as a single linguistic operation, this would fit well with it, though Rumfitt doubtless (as a fan of classical logic) prefers to negation sentences.
18895 Logic which maps ordinary reasoning must be transparent, and free of variables [Sommers]
     Full Idea: What would a 'laws of thought' logic that cast light on natural language deductive thinking be like? Such a logic must be variable-free, conforming to normal syntax, and its modes of reasoning must be transparent, to make them virtually instantaneous.
     From: Fred Sommers (Intellectual Autobiography [2005], 'How We')
     A reaction: This is the main motivation for Fred Sommers's creation of modern term logic. Even if you are up to your neck in modern symbolic logic (which I'm not), you have to find this idea appealing. You can't leave it to the psychologists.
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
11211 If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt]
     Full Idea: If a designated conclusion follows from the premisses, but the argument involves two howlers which cancel each other out, then the moral is that the path an argument takes from premisses to conclusion does matter to its logical evaluation.
     From: Ian Rumfitt ("Yes" and "No" [2000], II)
     A reaction: The drift of this is that our view of logic should be a little closer to the reasoning of ordinary language, and we should rely a little less on purely formal accounts.
5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
18897 Predicate logic has to spell out that its identity relation '=' is an equivalent relation [Sommers]
     Full Idea: Because predicate logic contrues identities dyadically, its account of inferences involving identity propositions needs laws or axioms of identity, explicitly asserting that the dyadic realtion in 'x=y' possesses symmetry, reflexivity and transitivity.
     From: Fred Sommers (Intellectual Autobiography [2005], 'Syllogistic')
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
18893 Translating into quantificational idiom offers no clues as to how ordinary thinkers reason [Sommers]
     Full Idea: Modern predicate logic's methods of justification, which involve translation into an artificial quantificational idiom, offer no clues to how the average person, knowing no logic and adhering to the vernacular, is so logically adept.
     From: Fred Sommers (Intellectual Autobiography [2005], Intro)
     A reaction: Of course, people are very logically adept when the argument is simple (because, I guess, they can test it against the world), but not at all good when the reasoning becomes more complex. We do, though, reason in ordinary natural language.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
11210 Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt]
     Full Idea: If 'and' and 'but' really are alike in sense, in what might that likeness consist? Some philosophers of classical logic will reply that they share a sense by virtue of sharing a truth table.
     From: Ian Rumfitt ("Yes" and "No" [2000])
     A reaction: This is the standard view which Rumfitt sets out to challenge.
11212 The sense of a connective comes from primitively obvious rules of inference [Rumfitt]
     Full Idea: A connective will possess the sense that it has by virtue of its competent users' finding certain rules of inference involving it to be primitively obvious.
     From: Ian Rumfitt ("Yes" and "No" [2000], III)
     A reaction: Rumfitt cites Peacocke as endorsing this view, which characterises the logical connectives by their rules of usage rather than by their pure semantic value.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / c. not
18903 Sommers promotes the old idea that negation basically refers to terms [Sommers, by Engelbretsen]
     Full Idea: If there is one idea that is the keystone of the edifice that constitutes Sommers's united philosophy it is that terms are the linguistic entities subject to negation in the most basic sense. It is a very old idea, tending to be rejected in modern times.
     From: report of Fred Sommers (Intellectual Autobiography [2005]) by George Engelbretsen - Trees, Terms and Truth 2
     A reaction: Negation in modern logic is an operator applied to sentences, typically writing '¬Fa', which denies that F is predicated of a, with Fa being an atomic sentence. Do we say 'not(Stan is happy)', or 'not-Stan is happy', or 'Stan is not-happy'? Third one?
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
18894 Predicates form a hierarchy, from the most general, down to names at the bottom [Sommers]
     Full Idea: We organise our concepts of predicability on a hierarchical tree. At the top are terms like 'interesting', 'exists', 'talked about', which are predicable of anything. At the bottom are names, and in between are predicables of some things and not others.
     From: Fred Sommers (Intellectual Autobiography [2005], 'Category')
     A reaction: The heirarchy seem be arranged simply by the scope of the predicate. 'Tallest' is predicable of anything in principle, but only of a few things in practice. Is 'John Doe' a name? What is 'cosmic' predicable of? Challenging!
7. Existence / D. Theories of Reality / 2. Realism
18900 Unfortunately for realists, modern logic cannot say that some fact exists [Sommers]
     Full Idea: Unfortunately for the fate of realist philosophy, modern logic's treatment of 'exists' is resolutely inhospitable to facts as referents of phrases of the form 'the existence or non-existence of φ'.
     From: Fred Sommers (Intellectual Autobiography [2005], 'Realism')
     A reaction: Predicate logic has to talk about objects, and then attribute predicates to them. It tends to treat a fact as 'Fa' - this object has this predicate, but that's not really how we understand facts.
19. Language / B. Reference / 1. Reference theories
18898 In standard logic, names are the only way to refer [Sommers]
     Full Idea: In modern predicate logic, definite reference by proper names is the primary and sole form of reference.
     From: Fred Sommers (Intellectual Autobiography [2005], 'Reference')
     A reaction: Hence we have to translate definite descriptions into (logical) names, or else paraphrase them out of existence. The domain only contains 'objects', so only names can uniquely pick them out.
19. Language / F. Communication / 3. Denial
11214 We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt]
     Full Idea: The standard view is that affirming not-A is more complex than affirming the atomic sentence A itself, with the latter determining its sense. But we could learn 'not' directly, by learning at once how to either affirm A or reject A.
     From: Ian Rumfitt ("Yes" and "No" [2000], IV)
     A reaction: [compressed] This seems fairly anti-Fregean in spirit, because it looks at the psychology of how we learn 'not' as a way of clarifying what we mean by it, rather than just looking at its logical behaviour (and thus giving it a secondary role).