27 ideas
| 8820 | Rules of reasoning precede the concept of truth, and they are what characterize it [Pollock] |
| Full Idea: Rather than truth being fundamental and rules for reasoning being derived from it, the rules for reasoning come first and truth is characterized by the rules for reasoning about truth. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Cog.Mach') | |
| A reaction: This nicely disturbs our complacency about such things. There is plenty of reasoning in Homer, but I bet there is no talk of 'truth'. Pontius Pilate seems to have been a pioneer (Idea 8821). Do the truth tables define or describe logical terms? |
| 8819 | We need the concept of truth for defeasible reasoning [Pollock] |
| Full Idea: It might be wondered why we even have a concept of truth. The answer is that this concept is required for defeasible reasoning. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Cog.Mach') | |
| A reaction: His point is that we must be able to think critically about our beliefs ('is p true?') if we are to have any knowledge at all. An excellent point. Give that man a teddy bear. |
| 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. |
| 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. |
| 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. |
| 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. |
| 8822 | Statements about necessities need not be necessarily true [Pollock] |
| Full Idea: True statements about the necessary properties of things need not be necessarily true. The well-known example is that the number of planets (9) is necessarily an odd number. The necessity is de re, but not de dicto. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Nat.Internal') | |
| A reaction: This would be a matter of the scope (the placing of the brackets) of the 'necessarily' operator in a formula. The quick course in modal logic should eradicate errors of this kind in your budding philosopher. |
| 8818 | Defeasible reasoning requires us to be able to think about our thoughts [Pollock] |
| Full Idea: Defeasible reasoning requires us to be able to think about our thoughts. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Cog.Mach') | |
| A reaction: This is why I do not think animals 'know' anything, though they seem to have lots of true beliefs about their immediate situation. |
| 8811 | What we want to know is - when is it all right to believe something? [Pollock] |
| Full Idea: When we ask whether a belief is justified, we want to know whether it is all right to believe it. The question we must ask is 'when is it permissible (epistemically) to believe P?'. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Ep.Norms') | |
| A reaction: Nice to see someone trying to get the question clear. The question clearly points to the fact that there must at least be some sort of social aspect to criteria of justification. I can't cheerfully follow my intuitions if everyone else laughs at them. |
| 8817 | Logical entailments are not always reasons for beliefs, because they may be irrelevant [Pollock] |
| Full Idea: Epistemologists have noted that logical entailments do not always constitute reasons. P may entail Q without the connection between P and Q being at all obvious. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Ref.of Extern') | |
| A reaction: Graham Priest and others try to develop 'relevance logic' to deal with this. This would deny the peculiar classical claim that everything is entailed by a falsehood. A belief looks promising if it entails lots of truths about the world. |
| 8814 | Epistemic norms are internalised procedural rules for reasoning [Pollock] |
| Full Idea: Epistemic norms are to be understood in terms of procedural knowledge involving internalized rules for reasoning. | |
| From: John L. Pollock (Epistemic Norms [1986], 'How regulate?') | |
| A reaction: He offers analogies with bicycly riding, but the simple fact that something is internalized doesn't make it a norm. Some mention of truth is needed, equivalent to 'don't crash the bike'. |
| 8823 | Reasons are always for beliefs, but a perceptual state is a reason without itself being a belief [Pollock] |
| Full Idea: When one makes a perceptual judgement on the basis of a perceptual state, I want to say that the perceptual state itself is one's reason. ..Reason are always reasons for beliefs, but the reasons themselves need not be beliefs. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Dir.Realism') | |
| A reaction: A crucial issue. I think I prefer the view of Davidson, in Ideas 8801 and 8804. Three options: a pure perception counts as a reason, or perceptions involve some conceptual content, or you only acquire a reason when a proposition is formulated. |
| 8813 | If we have to appeal explicitly to epistemic norms, that will produce an infinite regress [Pollock] |
| Full Idea: If we had to make explicit appeal to epistemic norms for justification (the 'intellectualist model') we would find ourselves in an infinite regress. The norms, their existence and their application would themselves have to be justified. | |
| From: John L. Pollock (Epistemic Norms [1986], 'How regulate?') | |
| A reaction: This is counter to the 'space of reasons' picture, where everything is rationally assessed. There are regresses for both reasons and for experiences, when they are offered as justifications. |
| 8812 | Norm Externalism says norms must be internal, but their selection is partly external [Pollock] |
| Full Idea: Norm Externalism acknowledges that the content of our epistemic norms must be internalist, but employs external considerations in the selection of the norms themselves. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Ep.Norms') | |
| A reaction: It can't be right that you just set your own norms, so this must contain some truth. Equally, even the most hardened externalist can't deny that what goes on in the head of the person concerned must have some relevance. |
| 8816 | Externalists tend to take a third-person point of view of epistemology [Pollock] |
| Full Idea: Externalists tend to take a third-person point of view in discussing epistemology. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Ref.of Extern') | |
| A reaction: Pollock's point, quite reasonably, is that the first-person aspect must precede any objective assessment of whether someone knows. External facts, such as unpublicised information, can undermine high quality internal justification. |
| 8815 | Belief externalism is false, because external considerations cannot be internalized for actual use [Pollock] |
| Full Idea: External considerations of reliability could not be internalized. Consequently, it is in principle impossible for us to actually employ externalist norms. I take this to be a conclusive refutation of belief externalism. | |
| From: John L. Pollock (Epistemic Norms [1986], 'Ref.of Extern') | |
| A reaction: Not so fast. He earlier rejected the 'intellectualist model' (Idea 8813), so he doesn't think norms have to be fully conscious and open to criticism. So they could be innate, or the result of indoctrination (sorry, teaching), or just forgotten. |
| 7388 | McGinn invites surrender, by saying it is hopeless trying to imagine conscious machines [Dennett on McGinn] |
| Full Idea: McGinn invites his readers to join him in surrender: It's just impossible to imagine how software could make a conscious robot. Don't even try, he says. Other philosophical experiments (involving China) "work" by dissuading readers from imagining. | |
| From: comment on Colin McGinn (The Problem of Consciousness [1991]) by Daniel C. Dennett - Consciousness Explained 14.1 | |
| A reaction: I agree with Dennett. If you don't try to imagine how robots might do it, you are also denied the right to try to imagine how brains might manage it. Admittedly this is hard, but good imagination needs study, effort, discussion, time, information... |
| 3185 | Multiple realisability rules out hidden essences and experts as the source of water- and gold-concepts [McGinn] |
| Full Idea: The multiple realisability emphasised by functionalists rules out the hidden essences (and the 'deferential' move in semantics) that one finds in the cases, for example, of "water" and "gold" emphasised by Kripke and Putnam. | |
| From: Colin McGinn (The Problem of Consciousness [1991], p.132) | |
| A reaction: Presumably if they are 'hidden', then the people to whom we 'defer' for our concepts can't actually know about the essences we are supposed to be discussing. You can mean essences without knowing them. Cf. Loch Ness Monster. |
| 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?' |
| 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. |