38 ideas
| 8220 | Philosophy is in a perpetual state of digression [Deleuze/Guattari] |
| Full Idea: Philosophy can be seen as being in a perpetual state of digression. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1) | |
| A reaction: Anyone who has ever tried to teach philosophy will vouch for this. Philosophy is the 'Arabian Nights', conjuring up wonderful stories, to avoid having to face something nasty. Philosophy is perpetual postponement of problems. |
| 8217 | Philosophy is a concept-creating discipline [Deleuze/Guattari] |
| Full Idea: Philosophy is the discipline that involves creating concepts. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], Intro) | |
| A reaction: One might very reasonably reply that Geography is a discipline which creates concepts. However, this emphasis is an interesting corrective to the school of analysis, which appears confined to existing, and even 'folk', concepts. |
| 8242 | Philosophy aims at what is interesting, remarkable or important - not at knowledge or truth [Deleuze/Guattari] |
| Full Idea: Philosophy does not consist in knowing, and is not inspired by truth. Rather, it is categories like Interesting, Remarkable, or Important that determine success or failure. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.3) | |
| A reaction: Speak for yourself. I wonder what the criteria are for 'Interesting' or 'Important'. They can't seriously count 'remarkable' as a criterion of philosophical success, can they? There can be remarkable stupidity. |
| 22270 | Frege changed philosophy by extending logic's ability to check the grounds of thinking [Potter on Frege] |
| Full Idea: Frege's 1879 logic transformed philosophy because it greatly expanded logic's reach - what thought can achieve unaided - and hence compelled a re-examination of everything previously said about the grounds of thought when logic gives out. | |
| From: comment on Gottlob Frege (Begriffsschrift [1879]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 Intro | |
| A reaction: I loved the gloss on logic as 'what thought can achieve unaided'. I largely see logic in terms of what is mechanically computable. |
| 8223 | The plague of philosophy is those who criticise without creating, and defend dead concepts [Deleuze/Guattari] |
| Full Idea: Those who criticise without creating, those who are content to defend the vanished concept without being able to give it the forces it needs to return to life, are the plague of philosophy. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1) | |
| A reaction: This seems to be the continental view of analytical philosophy, that it is pathetically conservative. I would offer MacIntyre as a response, who gives a beautiful analysis of why the super-modern view is dead. The French are hopelessly romantic. |
| 8247 | Phenomenology needs art as logic needs science [Deleuze/Guattari] |
| Full Idea: Phenomenology needs art as logic needs science. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 2.6) | |
| A reaction: I would have thought that it was science that needs logic. Art is more elitist than science, and less universal. I presume artists and phenomenologists share a target of deconstructing lived human experience. |
| 8939 | We should not describe human laws of thought, but how to correctly track truth [Frege, by Fisher] |
| Full Idea: Frege disagree that logic should merely describe the laws of thought - how people actually did reason. Logic is essentially normative, not descriptive. We want the one logic which successfully tracks the truth. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Jennifer Fisher - On the Philosophy of Logic 1.III | |
| A reaction: This explains Frege's sustained attack on psychologism, and it also explains we he ended up as a platonist about logic - because he wanted its laws to be valid independently of human thinking. A step too far, perhaps. Brains are truth machines. |
| 8224 | 'Eris' is the divinity of conflict, the opposite of Philia, the god of friendship [Deleuze/Guattari] |
| Full Idea: 'Eris' is the Greek divinity of discord, conflict, and strife, the complementary opposite of Philia, the divinity of union and friendship. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.2 n) | |
| A reaction: Are these actual gods? This interestingly implies that the wonders of dialectic and Socrates' elenchus are simply aspects of friendship, which was elevated by Epicurus to the highest good. The Greeks just wanted wonderful friends and fine speeches. |
| 4971 | I don't use 'subject' and 'predicate' in my way of representing a judgement [Frege] |
| Full Idea: A distinction of subject and predicate finds no place in my way of representing a judgement. | |
| From: Gottlob Frege (Begriffsschrift [1879], §03) | |
| A reaction: Perhaps this sentence could be taken as the beginning of modern analytical philosophy. The old view doesn't seem to me entirely redundant - merely replaced by a much more detailed analysis of what makes a 'subject' and what makes a 'predicate'. |
| 17745 | For Frege, 'All A's are B's' means that the concept A implies the concept B [Frege, by Walicki] |
| Full Idea: 'All A's are B's' meant for Frege that the concept A implies the concept B, or that to be A implies also to be B. Moreover this applies to arbitrary x which happens to be A. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Michal Walicki - Introduction to Mathematical Logic History D.2 | |
| A reaction: This seems to hit the renate/cordate problem. If all creatures with hearts also have kidneys, does that mean that being enhearted logically implies being kidneyfied? If all chimps are hairy, is that a logical requirement? Is inclusion implication? |
| 7728 | Frege has a judgement stroke (vertical, asserting or judging) and a content stroke (horizontal, expressing) [Frege, by Weiner] |
| Full Idea: Frege distinguished between asserting a proposition and expressing it, and he introduced the judgement stroke (a small vertical line, assertion) and the content stroke (a long horizontal line, expression) to represent them. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Joan Weiner - Frege Ch.3 | |
| A reaction: There are also strokes for conditional and denial. |
| 16881 | The laws of logic are boundless, so we want the few whose power contains the others [Frege] |
| Full Idea: Since in view of the boundless multitude of laws that can be enunciated we cannot list them all, we cannot achieve completeness except by searching out those that, by their power, contain all of them. | |
| From: Gottlob Frege (Begriffsschrift [1879], §13) | |
| A reaction: He refers to these laws in the previous sentence as the 'core'. His talk of 'power' is music to my ears, since it implies a direction of explanation. Burge says the power is that of defining other concepts. |
| 7622 | In 1879 Frege developed second order logic [Frege, by Putnam] |
| Full Idea: By 1879 Frege had discovered an algorithm, a mechanical proof procedure, that embraces what is today standard 'second order logic'. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Hilary Putnam - Reason, Truth and History Ch.5 | |
| A reaction: Note that Frege did more than introduce quantifiers, and the logic of predicates. |
| 8219 | Logic has an infantile idea of philosophy [Deleuze/Guattari] |
| Full Idea: Logic has an infantile idea of philosophy. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1) | |
| A reaction: This offers some explanation of why Anglo-American philosophers are steeped in logic, and the continentals just ignore it. I have some sympathy with the French view. Logic seems to study language with all the interesting part drained off. |
| 8246 | Logic hates philosophy, and wishes to supplant it [Deleuze/Guattari] |
| Full Idea: A real hatred inspires logic's rivalry with, or its will to supplant, philosophy. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 2.6) | |
| A reaction: A delightful corrective to the neurotic inferiority that most English-speaking philosophers feel about their failure to master logic. What was Aristotle playing at when he invented logic? Philosophical talent is utterly different from a talent for logic. |
| 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? |
| 9950 | A quantifier is a second-level predicate (which explains how it contributes to truth-conditions) [Frege, by George/Velleman] |
| Full Idea: The contribution of the quantifier to the truth conditions of sentences of which it is a part cannot be adequately explained if it is treated as other than a second-level predicate (for instance, if it is viewed as name). | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.2 | |
| A reaction: They suggest that this makes it something like a 'property of properties'. With this account it becomes plausible to think of numbers as quantifiers (since they do, after all, specify quantities). |
| 9991 | For Frege the variable ranges over all objects [Frege, by Tait] |
| Full Idea: For Frege the variable ranges over all objects. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by William W. Tait - Frege versus Cantor and Dedekind XII | |
| A reaction: The point is that Frege had not yet seen the necessity to define the domain of quantification, and this leads him into various difficulties. |
| 10536 | Frege's domain for variables is all objects, but modern interpretations first fix the domain [Dummett on Frege] |
| Full Idea: For Frege there is no need to specify the domain of the individual variables, which is taken as the totality of all objects. This contrasts with the standard notion of an interpretation, which demands that we first fix the domain. | |
| From: comment on Gottlob Frege (Begriffsschrift [1879]) by Michael Dummett - Frege Philosophy of Language (2nd ed) Ch.14 | |
| A reaction: What intrigues me is how domains of quantification shift according to context in ordinary usage, even in mid-sentence. I ought to go through every idea in this database, specifying its domain of quantification. Any volunteers? |
| 7742 | Frege reduced most quantifiers to 'everything' combined with 'not' [Frege, by McCullogh] |
| Full Idea: Frege treated 'everything' as basic, and suggested ways of recasting propositions containing other quantifiers so that this was the only one remaining. He recast 'something' as 'at least one thing', and defined this in terms of 'everything' and 'not'. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Gregory McCullogh - The Game of the Name 1.6 | |
| A reaction: Extreme parsimony seems highly desirable in logic as well as ontology, but it can lead to frustrations, especially over the crucial question of the existence of things quantified over. See Idea 6068. |
| 7730 | Frege introduced quantifiers for generality [Frege, by Weiner] |
| Full Idea: In order to express generality, Frege introduced quantifier notation. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Joan Weiner - Frege | |
| A reaction: This is the birth of predicate logic, beloved of analytical philosophers (but of no apparent interest to phenomenalists, deconstructionists, existentialists?). Generality is what you get from induction (which is, of course, problematic). |
| 13824 | Proof theory began with Frege's definition of derivability [Frege, by Prawitz] |
| Full Idea: Frege's formal definition of derivability is perhaps the first investigation in general proof theory. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Dag Prawitz - Gentzen's Analysis of First-Order Proofs 2 n2 | |
| A reaction: In 'On General Proof Theory §1' Prawitz says "proof theory originated with Hilbert" in 1900. Presumably Frege offered a theory, and then Hilbert saw it as a general project. |
| 13609 | Frege produced axioms for logic, though that does not now seem the natural basis for logic [Frege, by Kaplan] |
| Full Idea: Frege's work supplied a set of axioms for logic itself, at least partly because it was a well-known way of presenting the foundations in other disciplines, especially mathematics, but it does not nowadays strike us as natural for logic. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by David Kaplan - Dthat 5.1 | |
| A reaction: What Bostock has in mind is the so-called 'natural' deduction systems, which base logic on rules of entailment, rather than on a set of truths. The axiomatic approach uses a set of truths, plus the idea of possible contradictions. |
| 17855 | It may be possible to define induction in terms of the ancestral relation [Frege, by Wright,C] |
| Full Idea: Frege's account of the ancestral has made it possible, in effect, to define the natural numbers as entities for which induction holds. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Crispin Wright - Frege's Concept of Numbers as Objects 4.xix | |
| A reaction: This is the opposite of the approach in the Peano Axioms, where induction is used to define the natural numbers. |
| 10607 | Frege's logic has a hierarchy of object, property, property-of-property etc. [Frege, by Smith,P] |
| Full Idea: Frege's general logical system involves a type hierarchy, distinguishing objects from properties from properties-of-properties etc., with every item belonging to a determinate level. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Peter Smith - Intro to Gödel's Theorems 14.1 | |
| A reaction: The Theory of Types went on to apply this hierarchy to classes, where Frege's disastrous Basic Law V flattens the hierarchy of classes, putting them on the same level (Smith p.119) |
| 11008 | Existence is not a first-order property, but the instantiation of a property [Frege, by Read] |
| Full Idea: When Kant said that existence was not a property, what he meant was, according to Frege, that existence is not a first-order property - it is not a property of individuals but a property of properties, that the property has an instance. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Stephen Read - Thinking About Logic Ch.5 |
| 8221 | We cannot judge the Cogito. Must we begin? Must we start from certainty? Can 'I' relate to thought? [Deleuze/Guattari] |
| Full Idea: There is no point in wondering whether Descartes' Cogito is right or wrong. Is it necessary "to begin", and, if so, is it necessary to start from the point of view of a subjective certainty? Can thought be the verb of an I? There is no direct answer. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1) | |
| A reaction: A nice first sentence for a work of philosophy would be "It is necessary to begin". Is the Cogito the only idea that is beyond judgement? I fear a slippery slope here, which would paralyse all of our judgements - and would therefore be ridiculous. |
| 8222 | Concepts are superior because they make us more aware, and change our thinking [Deleuze/Guattari] |
| Full Idea: If one concept is 'better' than an earlier one, it is because it makes us aware of new variations and unknown resonances, it carries out unforeseen cuttings-out, it brings forth an Event that surveys (survole) us. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1) | |
| A reaction: I don't get much of that, but it is certainly in tune with the Kuhn/Feyerabend idea that what science can generate is fresh visions, rather than precisely expanded truths. Personally I consider it dangerous nonsense, but I thought I ought to pass it on. |
| 8218 | Other people completely revise our perceptions, because they are possible worlds [Deleuze/Guattari] |
| Full Idea: The concept of the Other Person as expression of a possible world in a perceptual field leads us to consider the components of this field in a new way. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.1) | |
| A reaction: I like the idea that other people are possible worlds. You can give reductionist accounts of the human animal till the cows come home, but when one walk into your visual field, the mind takes off. See Crusoe and Friday. |
| 8248 | Phenomenology says thought is part of the world [Deleuze/Guattari] |
| Full Idea: According to phenomenology, thought depends on man's relations with the world - with which the brain is necessarily in agreement because it is drawn from these relations. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], Conclusion) | |
| A reaction: The development of externalist views of mind, arising from the Twin Earth idea, seems to provide a link to continental philosophy, where similar ideas are found in Husserl, Sartre and Merleau-Ponty. So study science, psychology, or sociology? |
| 8245 | The logical attitude tries to turn concepts into functions, when they are really forms or forces [Deleuze/Guattari] |
| Full Idea: Logic is reductionist not accidentally, but essentially and necessarily: following the route marked out by Frege and Russell, it wants to turn the concept into a function (...when actually a concept is a form, or a force). | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 2.6) | |
| A reaction: [Last part on p.144] I'm not sure that I understand 'form or force', but the idea that concepts are mere functions is like describing something as 'transport', without saying whether it is bus/bike/train.. Is a concept a vision, or a tool? |
| 22280 | Frege's account was top-down and decompositional, not bottom-up and compositional [Frege, by Potter] |
| Full Idea: Frege's account was top-down, not bottom-up: he aimed to decompose and discern function-argument structure in already existing sentences, not to explain how those sentences acquired their meanings in the first place. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 03 'Func' | |
| A reaction: This goes with the holistic account of meaning, which leads to Quine's gavagai and Kuhn's obfuscation of science. I recommend compositionality for everthing. |
| 20416 | By 1790 aestheticians were mainly trying to explain individual artistic genius [Kemp] |
| Full Idea: By 1790 the idea that a central task for the aesthetician was to explain or at least adequately to describe the phenomenon of the individual artistic genius had definitely taken hold. | |
| From: Gary Kemp (Croce and Collingwood [2012], Intro) | |
| A reaction: Hence when Kant and Hegel write about art, though are only really thinking of the greatest art (which might be in touch with the sublime or Spirit etc.). Nowadays I think we expect accounts of art to cover modest amateur efforts as well. |
| 20417 | Expression can be either necessary for art, or sufficient for art (or even both) [Kemp] |
| Full Idea: Seeing art as expression has two components: 1) if something is a work of art, then it is expressive, 2) if something is expressive, then it is a work of art. So expression can be necessary or sufficient for art. (or both, for Croce and Collingwood). | |
| From: Gary Kemp (Croce and Collingwood [2012], 1) | |
| A reaction: I take the idea that art 'expresses' the feelings of an artist to be false. Artists are more like actors. Nearly all art has some emotional impact, which is of major importance, but I don't think 'expression' is a very good word for that. |
| 20418 | The horror expressed in some works of art could equallly be expressed by other means [Kemp] |
| Full Idea: The horror or terror of Edvard Much's 'The Scream' could in principle be expressed by different paintings, or even by works of music. | |
| From: Gary Kemp (Croce and Collingwood [2012], 1) | |
| A reaction: A very good simple point against the idea that the point of art is expression. It leaves out the very specific nature of each work of art! |
| 20419 | We don't already know what to express, and then seek means of expressing it [Kemp] |
| Full Idea: One cannot really know, or be conscious of, what it is that one is going to express, and then set about expressing it; indeed if one is genuinely conscious of it then one has already expressed it. | |
| From: Gary Kemp (Croce and Collingwood [2012], 1) | |
| A reaction: That pretty conclusively demolishes the idea that art is expression. I picture Schubert composing at the piano: he doesn't feel an emotion, and then hunt for its expression on the keyboard; he seeks out expressive phrases by playing. |
| 7741 | The predicate 'exists' is actually a natural language expression for a quantifier [Frege, by Weiner] |
| Full Idea: On Frege's logical analysis, the predicate 'exists' is actually a natural language expression for a quantifier. | |
| From: report of Gottlob Frege (Begriffsschrift [1879]) by Joan Weiner - Frege Ch.8 | |
| A reaction: However see Idea 6067, for McGinn's alternative view of quantifiers. In the normal conventions of predicate logic it may be that existence is treated as a quantifier, but that is not the same as saying that existence just IS a quantifier. |
| 8243 | Atheism is the philosopher's serenity, and philosophy's achievement [Deleuze/Guattari] |
| Full Idea: It is amazing that so many philosophers take the death of God as tragic. Atheism is not a drama, but the philosopher's serenity and philosophy's achievement. | |
| From: G Deleuze / F Guattari (What is Philosophy? [1991], 1.4) | |
| A reaction: It seems to me that it is the late nineteenth and early twentieth century that feels the death of God as a tragedy. Modern Anglo-American philosophers are mostly pretty serene on the subject, unless, like Dennett, they go on the offensive. |