31 ideas
3969 | There are no ultimate standards of rationality, since we only assess others by our own standard [Davidson] |
Full Idea: It makes no sense to speak of comparing or agreeing on ultimate standards of rationality, since it is our own standards in each case to which we must turn in interpreting others. This is not a failure of objectivity, but where 'questions come to an end'. | |
From: Donald Davidson (Davidson on himself [1994], p.232) | |
A reaction: This seems wrong, given the commitment to truth and charity in interpretation. He could have said the same about perception, but I doubt if he would. |
3972 | Truth and objectivity depend on a community of speakers to interpret what they mean [Davidson] |
Full Idea: The basis on which the concepts of truth and objectivity depend for application is a community of understanding, agreement among speakers on how each is to be understood. | |
From: Donald Davidson (Davidson on himself [1994], p.233) | |
A reaction: Obviously all understanding is, in practice, an interpretation by a community, but that isn't what 'truth' means. We mean 'true independently of any community'. |
18806 | Frege thought traditional categories had psychological and linguistic impurities [Frege, by Rumfitt] |
Full Idea: Frege rejected the traditional categories as importing psychological and linguistic impurities into logic. | |
From: report of Gottlob Frege (Function and Concept [1891]) by Ian Rumfitt - The Boundary Stones of Thought 1.2 | |
A reaction: Resisting such impurities is the main motivation for making logic entirely symbolic, but it doesn't follow that the traditional categories have to be dropped. |
10304 | Very few things in set theory remain valid in intuitionist mathematics [Bernays] |
Full Idea: Very few things in set theory remain valid in intuitionist mathematics. | |
From: Paul Bernays (On Platonism in Mathematics [1934]) |
8490 | First-level functions have objects as arguments; second-level functions take functions as arguments [Frege] |
Full Idea: Just as functions are fundamentally different from objects, so also functions whose arguments are and must be functions are fundamentally different from functions whose arguments are objects. The latter are first-level, the former second-level, functions. | |
From: Gottlob Frege (Function and Concept [1891], p.38) | |
A reaction: In 1884 he called it 'second-order'. This is the standard distinction between first- and second-order logic. The first quantifies over objects, the second over intensional entities such as properties and propositions. |
8492 | Relations are functions with two arguments [Frege] |
Full Idea: Functions of one argument are concepts; functions of two arguments are relations. | |
From: Gottlob Frege (Function and Concept [1891], p.39) | |
A reaction: Nowadays we would say 'two or more'. Another interesting move in the aim of analytic philosophy to reduce the puzzling features of the world to mathematical logic. There is, of course, rather more to some relations than being two-argument functions. |
10303 | Restricted Platonism is just an ideal projection of a domain of thought [Bernays] |
Full Idea: A restricted Platonism does not claim to be more than, so to speak, an ideal projection of a domain of thought. | |
From: Paul Bernays (On Platonism in Mathematics [1934], p.261) | |
A reaction: I have always found Platonism to be congenial when it talks of 'ideals', and ridiculous when it talks of a special form of 'existence'. Ideals only 'exist' because we idealise things. I may declare myself, after all, to be a Restricted Platonist. |
8487 | Arithmetic is a development of logic, so arithmetical symbolism must expand into logical symbolism [Frege] |
Full Idea: I am of the opinion that arithmetic is a further development of logic, which leads to the requirement that the symbolic language of arithmetic must be expanded into a logical symbolism. | |
From: Gottlob Frege (Function and Concept [1891], p.30) | |
A reaction: This may the the one key idea at the heart of modern analytic philosophy (even though logicism may be a total mistake!). Logic and arithmetical foundations become the master of ontology, instead of the servant. The jury is out on the whole enterprise. |
10306 | Mathematical abstraction just goes in a different direction from logic [Bernays] |
Full Idea: Mathematical abstraction does not have a lesser degree than logical abstraction, but rather another direction. | |
From: Paul Bernays (On Platonism in Mathematics [1934], p.268) | |
A reaction: His point is that the logicists seem to think that if you increasingly abstract from mathematics, you end up with pure logic. |
18899 | Frege takes the existence of horses to be part of their concept [Frege, by Sommers] |
Full Idea: Frege regarded the existence of horses as a property of the concept 'horse'. | |
From: report of Gottlob Frege (Function and Concept [1891]) by Fred Sommers - Intellectual Autobiography 'Realism' |
4028 | Frege allows either too few properties (as extensions) or too many (as predicates) [Mellor/Oliver on Frege] |
Full Idea: Frege's theory of properties (which he calls 'concepts') yields too few properties, by identifying coextensive properties, and also too many, by letting every predicate express a property. | |
From: comment on Gottlob Frege (Function and Concept [1891]) by DH Mellor / A Oliver - Introduction to 'Properties' §2 | |
A reaction: Seems right; one extension may have two properties (have heart/kidneys), two predicates might express the same property. 'Cutting nature at the joints' covers properties as well as objects. |
8489 | The concept 'object' is too simple for analysis; unlike a function, it is an expression with no empty place [Frege] |
Full Idea: I regard a regular definition of 'object' as impossible, since it is too simple to admit of logical analysis. Briefly: an object is anything that is not a function, so that an expression for it does not contain any empty place. | |
From: Gottlob Frege (Function and Concept [1891], p.32) | |
A reaction: Here is the core of the programme for deriving our ontology from our logic and language, followed through by Russell and Quine. Once we extend objects beyond the physical, it becomes incredibly hard to individuate them. |
3960 | There are no such things as minds, but people have mental properties [Davidson] |
Full Idea: There are no such things as minds, but people have mental properties. | |
From: Donald Davidson (Davidson on himself [1994], p.231) | |
A reaction: I think this is right. It fits with Searle's notion of consciousness as a property, like the liquidity of water. I don't panic if I think "I have no mind, but I have extraordinary properties". |
3964 | If the mind is an anomaly, this makes reduction of the mental to the physical impossible [Davidson] |
Full Idea: If there are no strict psychophysical laws, this rules out reductionism, either by definition of mental predicates in physical terms, or by way of bridging laws. | |
From: Donald Davidson (Davidson on himself [1994], p.231) | |
A reaction: But it is by no means clear that there are no psycho-physical laws. How could this be known a priori? |
3963 | There are no strict psychophysical laws connecting mental and physical events [Davidson] |
Full Idea: There are no strict psychophysical laws (that is, laws connecting mental events under their mental descriptions with physical events under their physical descriptions). | |
From: Donald Davidson (Davidson on himself [1994], p.231) | |
A reaction: This is clearly open to question. It may be just that no human mind could ever grasp such laws, given their probable complexity. |
3961 | Obviously all mental events are causally related to physical events [Davidson] |
Full Idea: All mental events are causally related to physical events. ..This seems obvious. | |
From: Donald Davidson (Davidson on himself [1994], p.231) | |
A reaction: All mental events are physically caused. Some bodily physical events result from mental events. Probably all mental events have some effect of other mental events (all of which are in some sense physical). |
3965 | Mental entities do not add to the physical furniture of the world [Davidson] |
Full Idea: Mental entities do not add to the physical furniture of the world. | |
From: Donald Davidson (Davidson on himself [1994], p.231) | |
A reaction: This seems to me clearly true, however we propose to characterise mental events. |
3966 | The correct conclusion is ontological monism combined with conceptual dualism [Davidson] |
Full Idea: My basic premises lead to the conclusion of ontological monism coupled with conceptual dualism (like Spinoza, except that he denied mental causation). | |
From: Donald Davidson (Davidson on himself [1994], p.231) | |
A reaction: 'Conceptual dualism' implies no real difference, but 'property dualism' is better, suggesting different properties when viewed from different angles. |
3967 | Absence of all rationality would be absence of thought [Davidson] |
Full Idea: To imagine a totally irrational animal is to imagine an animal without thought. | |
From: Donald Davidson (Davidson on himself [1994], p.232) | |
A reaction: This wouldn't be so clear without the theory of evolution, which suggests that only the finders of truth last long enough to breed. |
3974 | Our meanings are partly fixed by events of which we may be ignorant [Davidson] |
Full Idea: What we mean by what we say is partly fixed by events of which we may be ignorant. | |
From: Donald Davidson (Davidson on himself [1994], p.235) | |
A reaction: There is 'strict and literal meaning', which is fixed by the words, even if I don't know what I am saying. But 'speaker's meaning' is surely a pure matter of a state of mind? |
9947 | Concepts are the ontological counterparts of predicative expressions [Frege, by George/Velleman] |
Full Idea: Concepts, for Frege, are the ontological counterparts of predicative expressions. | |
From: report of Gottlob Frege (Function and Concept [1891]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.2 | |
A reaction: That sounds awfully like what many philosophers call 'universals'. Frege, as a platonist (at least about numbers), I would take to be in sympathy with that. At least we can say that concepts seem to be properties. |
10319 | An assertion about the concept 'horse' must indirectly speak of an object [Frege, by Hale] |
Full Idea: Frege had a notorious difficulty over the concept 'horse', when he suggests that if we wish to assert something about a concept, we are obliged to proceed indirectly by speaking of an object that represents it. | |
From: report of Gottlob Frege (Function and Concept [1891], Ch.2.II) by Bob Hale - Abstract Objects | |
A reaction: This sounds like the thin end of a wedge. The great champion of objects is forced to accept them here as a façon de parler, when elsewhere they have ontological status. |
8488 | A concept is a function whose value is always a truth-value [Frege] |
Full Idea: A concept in logic is closely connected with what we call a function. Indeed, we may say at once: a concept is a function whose value is always a truth-value. ..I give the name 'function' to what is meant by the 'unsaturated' part. | |
From: Gottlob Frege (Function and Concept [1891], p.30) | |
A reaction: So a function becomes a concept when the variable takes a value. Problems arise when the value is vague, or the truth-value is indeterminable. |
9948 | Unlike objects, concepts are inherently incomplete [Frege, by George/Velleman] |
Full Idea: For Frege, concepts differ from objects in being inherently incomplete in nature. | |
From: report of Gottlob Frege (Function and Concept [1891]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.2 | |
A reaction: This is because they are 'unsaturated', needing a quantified variable to complete the sentence. This could be a pointer towards Quine's view of properties, as simply an intrinsic feature of predication about objects, with no separate identity. |
4972 | I may regard a thought about Phosphorus as true, and the same thought about Hesperus as false [Frege] |
Full Idea: From sameness of meaning there does not follow sameness of thought expressed. A fact about the Morning Star may express something different from a fact about the Evening Star, as someone may regard one as true and the other false. | |
From: Gottlob Frege (Function and Concept [1891], p.14) | |
A reaction: This all gets clearer if we distinguish internalist and externalist theories of content. Why take sides on this? Why not just ask 'what is in the speaker's head?', 'what does the sentence mean in the community?', and 'what is the corresponding situation?' |
3968 | Propositions explain nothing without an explanation of how sentences manage to name them [Davidson] |
Full Idea: The idea of a proposition is unhelpful, until it is explained how exactly the words in the contained sentence manage to name or describe a proposition (which even Frege failed to achieve). | |
From: Donald Davidson (Davidson on himself [1994], p.232) | |
A reaction: It seems obvious to me that there are brain events best labelled as propositions, even if their fit with language is puzzling. |
3970 | Thought is only fully developed if we communicate with others [Davidson] |
Full Idea: We would have no fully-fledge thoughts if we were not in communication with others. | |
From: Donald Davidson (Davidson on himself [1994], p.233) | |
A reaction: This seems a plausible empirical observation, though I would doubt any a priori proof of it. If animals could speak, they would become intellectuals? |
3971 | There is simply no alternative to the 'principle of charity' in interpreting what others do [Davidson] |
Full Idea: The 'principle of charity' is a misleading term, since there is no alternative if we want to make sense of the attitudes and actions of the agents around us. | |
From: Donald Davidson (Davidson on himself [1994], p.233) | |
A reaction: I suppose so, but only with a background of evolutionary theory. I would necessarily assume charity if a robot spoke to me. |
3973 | Without a teacher, the concept of 'getting things right or wrong' is meaningless [Davidson] |
Full Idea: Without a 'teacher', nothing would give content to the idea that there is a difference between getting things right and getting them wrong. | |
From: Donald Davidson (Davidson on himself [1994], p.234) | |
A reaction: Seems right. A group of speculators with no one in the role of 'teacher' would seem to be paralysed with uncertain (except where judgements are very obvious). |
3962 | Cause and effect relations between events must follow strict laws [Davidson] |
Full Idea: If two events are related as cause and effect, there is a strict law under which they may be subsumed. | |
From: Donald Davidson (Davidson on himself [1994], p.231) | |
A reaction: Davidson admits that this is open to challenge (though Hume and Kant supported it). It does seem to be central to our understanding of nature. |
8491 | The Ontological Argument fallaciously treats existence as a first-level concept [Frege] |
Full Idea: The ontological proof of God's existence suffers from the fallacy of treating existence as a first-level concept. | |
From: Gottlob Frege (Function and Concept [1891], p.38 n) | |
A reaction: [See Idea 8490 for first- and second-order functions] This is usually summarised as the idea that existence is a quantifier rather than a predicate. |