| 18896 | Aristotle places terms at opposite ends, joined by a quantified copula [Aristotle, by Sommers] |
| Full Idea: Aristotle often preferred to formulate predications by placing the terms at opposite ends of the sentence and joining them by predicating expressions like 'belongs-to-some' or 'belongs-to-every'. | |
| From: report of Aristotle (Prior Analytics [c.328 BCE]) by Fred Sommers - Intellectual Autobiography 'Conceptions' | |
| A reaction: This is Sommers's picture of Aristotle, which led Sommers to develop his modern Term Logic. |
| 4730 | For Aristotle, the subject-predicate structure of Greek reflected a substance-accident structure of reality [Aristotle, by O'Grady] |
| Full Idea: Aristotle apparently believed that the subject-predicate structure of Greek reflected the substance-accident nature of reality. | |
| From: report of Aristotle (works [c.330 BCE]) by Paul O'Grady - Relativism Ch.4 | |
| A reaction: We need not assume that Aristotle is wrong. It is a chicken-and-egg. There is something obvious about subject-predicate language, if one assumes that unified objects are part of nature, and not just conventional. |
| 21400 | Stoics avoided universals by paraphrasing 'Man is...' as 'If something is a man, then it is...' [Stoic school, by Long] |
| Full Idea: Stoics reduced universals to thoughts or concepts, ...so in order to make universal statements which would not conflict with their metaphysics, they rephrased sentences of the form 'Man is...' as conditionals: 'If something is a man, then it is...' | |
| From: report of Stoic school (fragments/reports [c.200 BCE]) by A.A. Long - Hellenistic Philosophy 4.3.3 | |
| A reaction: [reference to Sextus, Adv Math 9.8] Predicate logic handles this with ease. It is something like the strategy of Ramsey sentences, for eliminating metaphysical properties. |
| 6020 | 'Man is a rational mortal animal' is equivalent to 'if something is a man, that thing is a rational mortal animal' [Sext.Empiricus] |
| Full Idea: Definitions are identical to universal propositions in meaning, and only differ in syntax, for whoever says 'Man is a rational mortal animal' says the same thing in meaning as whoever says 'If something is a man, that thing is a rational mortal animal'. | |
| From: Sextus Empiricus (Against the Professors (six books) [c.180], 11.8) | |
| A reaction: How strikingly like Bertrand Russell's interest and solutions. Sextus shows a straightforward interest in logical form, of a kind we associate with the twentieth century. Did Sextus Empiricus invent quantification? |
| 7729 | Frege replaced Aristotle's subject/predicate form with function/argument form [Frege, by Weiner] |
| Full Idea: Frege's regimentation is based on the view of the simplest sort of statement as having, not subject/predicate form (as in Aristotle), but function/argument form. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Joan Weiner - Frege | |
| A reaction: This looks like being a crucial move into the modern world, where one piece of information is taken in and dealt with, as in computer procedures. Have educated people reorganised their minds along Fregean lines? |
| 4975 | A thought can be split in many ways, so that different parts appear as subject or predicate [Frege] |
| Full Idea: A thought can be split up in many ways, so that now one thing, now another, appears as subject or predicate | |
| From: Gottlob Frege (On Concept and Object [1892], p.199) | |
| A reaction: Thus 'the mouse is in the box', and 'the box contains the mouse'. A simple point, but important when we are trying to distinguish thought from language. |
| 8645 | Convert "Jupiter has four moons" into "the number of Jupiter's moons is four" [Frege] |
| Full Idea: The proposition "Jupiter has four moons" can be converted into "the number of Jupiter's moons is four". | |
| From: Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884], §57) | |
| A reaction: This seems to be the beginning of the modern exploration of the whole idea of logical form. It is one thing to find a logical forms which suits your current thesis (here, that numbers are not adjectival), but another to prove that it is the right form. |
| 6115 | Vagueness, and simples being beyond experience, are obstacles to a logical language [Russell] |
| Full Idea: The fact that we do not experience simples is one obstacle to the actual creation of a correct logical language, and vagueness is another. | |
| From: Bertrand Russell (Logical Atomism [1924], p.159) | |
| A reaction: The dream of creating a perfect logical language looks doomed from the start, but it is a very interesting project to try to pinpoint why it is unlikely to be possible. I say a perfect language cuts nature exactly at the joints, so find the joints. |
| 7528 | Leibniz bases everything on subject/predicate and substance/property propositions [Russell] |
| Full Idea: The metaphysics of Leibniz was explicitly based upon the doctrine that every proposition attributes a predicate to a subject and (what seemed to him almost the same thing) that every fact consists of a substance having a property. | |
| From: Bertrand Russell (My Philosophical Development [1959], Ch.5) | |
| A reaction: I think it is realised now that although predicates tend to attribute properties to things, they are far from being the same thing. See Idea 4587, for example. Russell gives us an interesting foot in the door of Leibniz's complex system. |
| 7758 | 'Elizabeth = Queen of England' is really a predication, not an identity-statement [Russell, by Lycan] |
| Full Idea: On Russell's view 'Elizabeth II = Queen of England' is only superficially an identity-statement; really it is a predication, and attributes a complex relational property to Elizabeth. | |
| From: report of Bertrand Russell (On Denoting [1905]) by William Lycan - Philosophy of Language Ch.1 | |
| A reaction: The original example is 'Scott = author of Waverley'. Why can't such statements be identities, in which the reference of one half of the identity is not yet known? 'The murderer is violent' and 'Smith is violent' suggests 'Smith is the murderer'. |
| 6092 | In a logically perfect language, there will be just one word for every simple object [Russell] |
| Full Idea: In a logically perfect language, there will be one word and no more for every simple object. | |
| From: Bertrand Russell (The Philosophy of Logical Atomism [1918], §II) | |
| A reaction: In other words, there would be no universals, only names? All that matters is that a language can successfully refer (unambiguously) to anything it wishes to. There must be better ways than Russell's lexical explosion. |
| 6101 | Romulus does not occur in the proposition 'Romulus did not exist' [Russell] |
| Full Idea: Romulus does not occur in the proposition 'Romulus did not exist'. | |
| From: Bertrand Russell (The Philosophy of Logical Atomism [1918], §VI) | |
| A reaction: A very nice paradoxical assertion, which captures the problem of finding the logical form for negative existential statements. Presumably the proposition refers to the mythical founder of Rome, though. He is not, I suppose, rigidly designated. |
| 18276 | A statement's logical form derives entirely from its constituents [Wittgenstein] |
| Full Idea: The logical form of the statement must already be given in the forms of its constituents. | |
| From: Ludwig Wittgenstein (Notebooks 1914-1916 [1915], 23e) | |
| A reaction: This would evidently require each constituent to have a 'logical form'. It is hard to see what that could beyond its part of speech. Do two common nouns have the same logical form? |
| 18743 | Wittgenstein says we want the grammar of problems, not their first-order logical structure [Wittgenstein, by Horsten/Pettigrew] |
| Full Idea: For the later Wittgenstein what we should be after is the grammatical structure of philosophical problems, not the first-order logical structure of such problems. | |
| From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Horsten,L/Pettigrew,R - Mathematical Methods in Philosophy 2 | |
| A reaction: This is the most sympathetic spin I have ever seen put on the apparent rather anti-philosophical later Wittgenstein. I nurse doubts about highly formal approaches to philosophy, and maybe 'grammar' (whatever that is) is our target. |
| 18268 | Apparent logical form may not be real logical form [Wittgenstein] |
| Full Idea: The apparent logical form of the proposition need not be its real logical form. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.0031), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 6 'The incom' | |
| A reaction: This is one of the key doctrines of modern analytic philosophy. |
| 22434 | Reduction to logical forms first simplifies idioms and grammar, then finds a single reading of it [Quine] |
| Full Idea: Ordinary language is reduced to logical form in two ways: reduction of the variety of idioms and grammatical constructions, and reduction of each surviving idiom to one fixed and convenient interpretation. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], V) | |
| A reaction: Is there a conflict between a 'fixed' and a 'convenient' result? By 'fixed' I suppose he means it is a commitment (to not waver). What is the logical form of a sentence which is deliberately ambiguous? |
| 8358 | There are no rules for the exact logic of ordinary language, because that doesn't exist [Strawson,P] |
| Full Idea: Neither Aristotelian nor Russellian rules give the exact logic of any expression of ordinary language; for ordinary language has no exact logic. | |
| From: Peter F. Strawson (On Referring [1950], §5) | |
| A reaction: This seems to imply that it is impossible to find precise logical forms, because of the pragmatic element in language, but I don't see why. Even more extreme modern pragmatics (where meaning is shifted) doesn't rule out precise underlying propositions. |
| 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. |
| 7332 | There is a huge range of sentences of which we do not know the logical form [Davidson] |
| Full Idea: We do not know the logical form of sentences about counterfactuals, probabilities, causal relations, belief, perception, intention, purposeful action, imperatives, optatives, or interrogatives, or the role of adverbs, adjectives or mass terms. | |
| From: Donald Davidson (Truth and Meaning [1967], p.35) | |
| A reaction: [compressed] This is the famous 'Davidson programme', where teams of philosophers work out the logical forms for this lot, thus unravelling the logic of the world. If they are beavering away, some sort of overview should have emerged by now... |
| 3080 | Logical form is the part of a sentence structure which involves logical elements [Harman] |
| Full Idea: The logical form of a sentence is that part of its structure that involves logical elements. | |
| From: Gilbert Harman (Thought [1973], 5.2) |
| 3081 | A theory of truth in a language must involve a theory of logical form [Harman] |
| Full Idea: Some sort of theory of logical form is involved in any theory of truth for a natural language. | |
| From: Gilbert Harman (Thought [1973], 5.2) |
| 3084 | Our underlying predicates represent words in the language, not universal concepts [Harman] |
| Full Idea: The underlying truth-conditional structures of thoughts are language-dependent in the sense that underlying predicates represent words in the language rather than universal concepts common to all languages. | |
| From: Gilbert Harman (Thought [1973], 6.3) |
| 16464 | We regiment to get semantic structure, for evaluating arguments, and understanding complexities [Stalnaker] |
| Full Idea: The point of regimentation is to give a perspicuous representation of the semantic structure of an expression, making it easier to evaluate the validity of arguments and to interpret complex statements. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4.2) | |
| A reaction: This is an authoritative summary from an expert of why all philosophers must take an interest in logical form. |
| 8132 | We now have a much more sophisticated understanding of logical form in language [Burge] |
| Full Idea: The second half of the twentieth century has seen the development of a vastly more sophisticated sense of logical form, as applied to natural languages. | |
| From: Tyler Burge (Philosophy of Mind: 1950-2000 [2005], p.462) | |
| A reaction: Burge cites this as one of the three big modern developments (along with the critique of logical positivism, and direct reference/anti-individualism). Vagueness may be the last frontier for this development. |
| 6339 | Logical form is the aspects of meaning that determine logical entailments [Horwich] |
| Full Idea: The logical forms of the sentences in a language are those aspects of their meanings that determine the relations of deductive entailment holding amongst them. | |
| From: Paul Horwich (Truth (2nd edn) [1990], Ch.6.30) | |
| A reaction: A helpful definition. Not all sentences, therefore, need to have a 'logical form'. Is the logical form the same as the underlying proposition. The two must converge, given that propositions lack the ambiguity that is often found in sentences. |
| 2544 | Thoughts have a dual aspect: as they seem to introspection, and their underlying logical reality [McGinn] |
| Full Idea: Our thoughts have a kind of duality, corresponding to their surface appearance to introspection and their underlying logical reality. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.147) |
| 8072 | Sentences of apparent identical form can have different contextual meanings [Devlin] |
| Full Idea: "Safety goggles must be worn in the building" is clear enough, but "dogs must always be carried on the escalator" doesn't require us to head off in search of a dog. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 1) | |
| A reaction: A nice illustration of how the requirements of logical form will often take us beyond the strict and literal meaning of a sentence, into context, tone, allusion and subjective aspects. |
| 12220 | Is it the sentence-token or the sentence-type that has a logical form? [Fine,K] |
| Full Idea: Do we attribute a logical form to a sentence token because it is a token of a type with that form, or do we attribute a logical form to a sentence type because it is a type of a token with that form? | |
| From: Kit Fine (Quine on Quantifying In [1990], p.110) | |
| A reaction: Since I believe in propositions (as the unambiguous thought that lies behind a sentence), I take it that logical form concerns propositions, though strict logicians don't like this, for fear that logic spills into psychology. |
| 13632 | Finding the logical form of a sentence is difficult, and there are no criteria of correctness [Shapiro] |
| Full Idea: It is sometimes difficult to find a formula that is a suitable counterpart of a particular sentence of natural language, and there is no acclaimed criterion for what counts as a good, or even acceptable, 'translation'. | |
| From: Stewart Shapiro (Foundations without Foundationalism [1991], 1.1) |
| 18168 | 'Propositional functions' are propositions with a variable as subject or predicate [Maddy] |
| Full Idea: A 'propositional function' is generated when one of the terms of the proposition is replaced by a variable, as in 'x is wise' or 'Socrates'. | |
| From: Penelope Maddy (Naturalism in Mathematics [1997], I.1) | |
| A reaction: This implies that you can only have a propositional function if it is derived from a complete proposition. Note that the variable can be in either subject or in predicate position. It extends Frege's account of a concept as 'x is F'. |
| 10407 | Logical Form explains differing logical behaviour of similar sentences [Swoyer] |
| Full Idea: 'Logical Form' is a technical notion motivated by the observation that sentences with a similar surface structure may exhibit quite different logical behaviour. | |
| From: Chris Swoyer (Properties [2000], 4.2) | |
| A reaction: [Swoyer goes on to give some nice examples] The tricky question is whether each sentence has ONE logical form. Pragmatics warns us of the dangers. One needs to check numerous inferences from a given sentences, not just one. |
| 10373 | Logical form can't dictate metaphysics, as it may propose an undesirable property [Schaffer,J] |
| Full Idea: Logical form should not have the last word in metaphysics, since it might predicate a property that we have theoretical reason to reject. | |
| From: Jonathan Schaffer (The Metaphysics of Causation [2007], 1.3.1) | |
| A reaction: These kind of warnings need to be sounded all the time, to prevent logicians and language experts from pitching their tents in the middle of metaphysics. They are welcome guests only, |
| 10754 | In proof-theory, logical form is shown by the logical constants [Rossberg] |
| Full Idea: A proof-theorist could insist that the logical form of a sentence is exhibited by the logical constants that it contains. | |
| From: Marcus Rossberg (First-order Logic, 2nd-order, Completeness [2004], §2) | |
| A reaction: You have to first get to the formal logical constants, rather than the natural language ones. E.g. what is the truth table for 'but'? There is also the matter of the quantifiers and the domain, and distinguishing real objects and predicates from bogus. |
| 18741 | Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew] |
| Full Idea: Logical formalization forces the investigator to make the central philosophical concepts precise. It can also show how some philosophical concepts and objects can be defined in terms of others. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 2) | |
| A reaction: This is the main rationale of the highly formal and mathematical approach to such things. The downside is when you impose 'precision' on language that was never intended to be precise. |
| 18905 | Propositions can be analysed as pairs of terms glued together by predication [Engelbretsen] |
| Full Idea: Sommers's 'tree theory' of predication assumes that propositions can be analysed as pairs of terms joined by some kind of predicational glue. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 2) | |
| A reaction: This is the basis of Sommers's upgraded Aristotelian logic, known as Term Logic. The idea of reasoning with 'terms', rather than with objects, predicates and quantifiers, seems to me very appealing. I think I reason more about facts than about objects. |
| 18922 | Logical syntax is actually close to surface linguistic form [Engelbretsen] |
| Full Idea: The underlying logical syntax of language is close to the surface syntax of ordinary language. | |
| From: George Engelbretsen (Trees, Terms and Truth [2005], 5) | |
| A reaction: This is the boast of the Term logicians, in opposition to the strained and unnatural logical forms of predicate logic, which therefore don't give a good account of the way ordinary speakers reason. An attractive programme. 'Terms' are the key. |