34 ideas
7623 | For ancient Greeks being wise was an ethical value [Putnam] |
Full Idea: An ancient Greek would have said that being wise is an ethical value. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.6) | |
A reaction: This is instantly appealing, but since the Enlightenment we are under an obligation to attempt to justify absolutely everything, including the value of wisdom. I'm thinking that it only has value if it leads to eudaimonia. |
23367 | Even pointing a finger should only be done for a reason [Epictetus] |
Full Idea: Philosophy says it is not right even to stretch out a finger without some reason. | |
From: Epictetus (fragments/reports [c.57], 15) | |
A reaction: The key point here is that philosophy concerns action, an idea on which Epictetus is very keen. He rather despise theory. This idea perfectly sums up the concept of the wholly rational life (which no rational person would actually want to live!). |
13838 | A decent modern definition should always imply a semantics [Hacking] |
Full Idea: Today we expect that anything worth calling a definition should imply a semantics. | |
From: Ian Hacking (What is Logic? [1979], §10) | |
A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives. |
4714 | Putnam's epistemic notion of truth replaces the realism of correspondence with ontological relativism [Putnam, by O'Grady] |
Full Idea: Putnam replaces a correspondence theory of truth with an epistemic notion of truth - truth is idealized rational acceptability. The correspondence theory is committed to realism, but his allows ontological relativism. | |
From: report of Hilary Putnam (Reason, Truth and History [1981]) by Paul O'Grady - Relativism Ch.3 | |
A reaction: This seems to be part of a slide by Putnam away from realism towards pragmatism. As a robust and defiant realist, this always strikes me as the road to hell. |
7617 | Before Kant, all philosophers had a correspondence theory of truth [Putnam] |
Full Idea: Before Kant it is impossible to find any philosopher who did not have a correspondence theory of truth. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.3) | |
A reaction: I don't believe this is true of Descartes. See ideas 2266 and 4298. Truth is 'clear and distinct' conceptions, but if you enlarge (and maybe socialise) 'clear' you get coherent. Descartes firmly avoids correspondence, because he can't trust 'facts'. |
4716 | The correspondence theory is wrong, because there is no one correspondence between reality and fact [Putnam, by O'Grady] |
Full Idea: Putnam argues that theory does not correspond to reality, because there are myriad correspondences possible, and we cannot single out "the" relation of correspondence. | |
From: report of Hilary Putnam (Reason, Truth and History [1981]) by Paul O'Grady - Relativism Ch.3 | |
A reaction: This obviously depends on views about reference and meaning. I don't see the problem in simple cases, which is all the correspondence theory needs. Complex cases, like chemistry, may well have ambiguities, but so what? |
7616 | Truth is an idealisation of rational acceptability [Putnam] |
Full Idea: Truth is an idealisation of rational acceptability; we speak as if there were such things as epistemically ideal conditions, and we call a statement 'true' if it would be justified under such conditions. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.3) | |
A reaction: The second part makes human beings sound stupid (which they are not), but the first part is right, and incredibly important. Peirce is behind Putnam's thought. Truth is the target of belief. It isn't a nonsense just because we can't be infallible. |
13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
Full Idea: 'Dilution' (or 'Thinning') provides an essential contrast between deductive and inductive reasoning; for the introduction of new premises may spoil an inductive inference. | |
From: Ian Hacking (What is Logic? [1979], §06.2) | |
A reaction: That is, inductive logic (if there is such a thing) is clearly non-monotonic, whereas classical inductive logic is monotonic. |
13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
Full Idea: If A |- B and B |- C, then A |- C. This generalises to: If Γ|-A,Θ and Γ,A |- Θ, then Γ |- Θ. Gentzen called this 'cut'. It is the transitivity of a deduction. | |
From: Ian Hacking (What is Logic? [1979], §06.3) | |
A reaction: I read the generalisation as 'If A can be either a premise or a conclusion, you can bypass it'. The first version is just transitivity (which by-passes the middle step). |
13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
Full Idea: Only the cut rule can have a conclusion that is less complex than its premises. Hence when cut is not used, a derivation is quite literally constructive, building up from components. Any theorem obtained by cut can be obtained without it. | |
From: Ian Hacking (What is Logic? [1979], §08) |
13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
Full Idea: I don't believe English is by nature classical or intuitionistic etc. These are abstractions made by logicians. Logicians attend to numerous different objects that might be served by 'If...then', like material conditional, strict or relevant implication. | |
From: Ian Hacking (What is Logic? [1979], §15) | |
A reaction: The idea that they are 'abstractions' is close to my heart. Abstractions from what? Surely 'if...then' has a standard character when employed in normal conversation? |
13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
Full Idea: First-order logic is the strongest complete compact theory with a Löwenheim-Skolem theorem. | |
From: Ian Hacking (What is Logic? [1979], §13) |
13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
Full Idea: Henkin proved that there is no first-order treatment of branching quantifiers, which do not seem to involve any idea that is fundamentally different from ordinary quantification. | |
From: Ian Hacking (What is Logic? [1979], §13) | |
A reaction: See Hacking for an example of branching quantifiers. Hacking is impressed by this as a real limitation of the first-order logic which he generally favours. |
13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
Full Idea: Second-order logic has no chance of a completeness theorem unless one ventures into intensional entities and possible worlds. | |
From: Ian Hacking (What is Logic? [1979], §13) |
13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
Full Idea: My doctrine is that the peculiarity of the logical constants resides precisely in that given a certain pure notion of truth and consequence, all the desirable semantic properties of the constants are determined by their syntactic properties. | |
From: Ian Hacking (What is Logic? [1979], §09) | |
A reaction: He opposes this to Peacocke 1976, who claims that the logical connectives are essentially semantic in character, concerned with the preservation of truth. |
13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
Full Idea: For some purposes the variables of first-order logic can be regarded as prepositions and place-holders that could in principle be dispensed with, say by a system of arrows indicating what places fall in the scope of which quantifier. | |
From: Ian Hacking (What is Logic? [1979], §11) | |
A reaction: I tend to think of variables as either pronouns, or as definite descriptions, or as temporary names, but not as prepositions. Must address this new idea... |
14203 | Intension is not meaning, as 'cube' and 'square-faced polyhedron' are intensionally the same [Putnam] |
Full Idea: Intension cannot be identified with meaning. ..'Cube' and 'regular polyhedron with six square faces' are logically equivalent predicates. The intension is the same (the function giving the cubes in any possible world) but there is a difference of meaning. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) |
14207 | If cats equal cherries, model theory allows reinterpretation of the whole language preserving truth [Putnam] |
Full Idea: If the number of cats happens to equal the cherries, then it follows from the theory of models that there is a reinterpretation of the entire language that leaves all sentences unchanged in truth value while permuting the extensions of 'cat' and 'cherry'. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) | |
A reaction: This horrifying result seems to come simply from the fact that there is an isomorphism between two models, which in turn seems to rest largely on the cardinality of the models. There seems to be something wrong with model theory here (?). |
13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic. | |
From: Ian Hacking (What is Logic? [1979], §13) | |
A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos. |
14214 | If we try to cure the abundance of theories with causal links, this is 'just more theory' [Putnam, by Lewis] |
Full Idea: If we try to base determinate reference on natural causal connection, Putnam says this is just more theory, as subject as any theory to overabundant, conflicting intended interpretations. | |
From: report of Hilary Putnam (Reason, Truth and History [1981]) by David Lewis - Putnam's Paradox 'Why Are' | |
A reaction: This is the 1981 Putnam, moving away from the realism that was implicit in the original causal theory of reference developed by himself and Kripke. His 'just more theory' is the slogan of Putnam's later anti-realism. |
14205 | The sentence 'A cat is on a mat' remains always true when 'cat' means cherry and 'mat' means tree [Putnam] |
Full Idea: The sentence 'A cat is on a mat' can be reinterpreted so that in the actual world 'cat' refers to cherries and 'mat' refers to trees, without affecting the truth-value of the sentence in any possible world. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) | |
A reaction: This simple suggestion is the basis of a notorious argument in favour of anti-realism. See D.Lewis's 'Putnam's Paradox'. It tracks back to Skolem's doubts about whether infinitary mathematics is possible. Putnam's conclusion sounds daft. |
7610 | A fact is simply what it is rational to accept [Putnam] |
Full Idea: I propose that the only criterion for what is a fact is what it is rational to accept. | |
From: Hilary Putnam (Reason, Truth and History [1981], Pref) | |
A reaction: An epistemological-ontological confusion here. The concept of a fact is of something which is the case quite independently of our criteria for believing it. There are facts which are unknowable for humans. It is, of course, rational to accept facts. |
7618 | Very nominalistic philosophers deny properties, though scientists accept them [Putnam] |
Full Idea: Some philosophers are so nominalistic that they would deny the existence of such entities as 'properties' altogether; but science itself does not hesitate to talk freely of properties. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.3) | |
A reaction: Maybe scientists aren't very good at ontology? They talk about forces and energy, but don't seem to know what they are. I am inclined to think that we must include properties in the working ontology of humans, but not into strict physics. |
4718 | If necessity is always relative to a description in a language, then there is only 'de dicto' necessity [Putnam, by O'Grady] |
Full Idea: Putnam endorses the view that necessity is relative to a description, so there is only necessity 'de dicto': relative to language, not to reality. | |
From: report of Hilary Putnam (Reason, Truth and History [1981]) by Paul O'Grady - Relativism Ch.3 | |
A reaction: Even a realist must take this proposal seriously. The facts may contain de re necessities, but we could be very sceptical about our capacity to know them. Personally I enjoy speculating about de re necessities. They can't stop you. |
7620 | Some kind of objective 'rightness' is a presupposition of thought itself [Putnam] |
Full Idea: What the relativist fails to see is that it is a presupposition of thought itself that some kind of objective 'rightness' exists. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.5) | |
A reaction: This may be the key objection to relativism. If you have a frame of reference, is it a good one? If you have a new perspective, is it better than your old one? Is the culture you live in confused or clear-thinking? Jokes and metaphors rely on truth. |
14204 | Naïve operationalism would have meanings change every time the tests change [Putnam] |
Full Idea: On a naïve operationalist account every time a new way of testing whether a substance is really gold is discovered, the meaning and reference of 'gold' undergoes a change. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) |
7611 | Rationality is one part of our conception of human flourishing [Putnam] |
Full Idea: Our notion of rationality is, at bottom, just one part of our conception of human flourishing, our idea of the good. | |
From: Hilary Putnam (Reason, Truth and History [1981], Pref) | |
A reaction: This looks like the beginnings of virtue epistemology, since rationality will have criteria, which would seem to be virtues. I find this idea appealing, both as a view of rationality, and as a view of the human good. |
14200 | 'Water' on Twin Earth doesn't refer to water, but no mental difference can account for this [Putnam] |
Full Idea: The word 'water' used on Twin Earth refers not to water but to this other liquid (XYZ). Yet there is no relevant difference in the mental state of Twin Earth speakers and speakers on Earth (in 1750) to account for this difference of reference. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) | |
A reaction: In this world, if you and I separately meet twins, and I think about this twin while you think about that one, our mental states are different even if they are indistinguishable. I know I'm thinking about my twin, not yours. Indexicals. |
7612 | Reference is social not individual, because we defer to experts when referring to elm trees [Putnam] |
Full Idea: My concept of an elm tree is exactly the same as my concept of a beech tree (I blush to confess), which shows that the determination of reference is social and not individual - both you and I defer to experts who can tell elms from beeches. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.1) | |
A reaction: If I said 'that tree looks nice' I wouldn't be deferring to experts. Nor if I said 'that tree, which I take to be an elm, looks nice'. If I am an expert I don't defer to experts. |
7613 | Concepts are (at least in part) abilities and not occurrences [Putnam] |
Full Idea: Concepts are (at least in part) abilities and not occurrences. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.1) | |
A reaction: This seems to be building on the idea that meaning is use, and also arises from a background of pragmatism. Perhaps a concept is an acquaintance with a node in platonic space? Lots of abilities aren't concepts, so what distinguishes the concepts? |
14202 | Neither individual nor community mental states fix reference [Putnam] |
Full Idea: Mental state (in either the individualistic or the collective sense) does not fix reference. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) | |
A reaction: The idea that communities fix reference seems to me plausible. See Tyler Burge on this. |
14201 | Maybe the total mental state of a language community fixes the reference of a term [Putnam] |
Full Idea: One might concede that the reference of a person's term isn't fixed by his individual mental state, but insist that the total mental state of all the members of the language community fixes the reference of the term. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) | |
A reaction: I like this reading of the problem, though Putnam himself prefers to say that things fix the reference. I take reference to be a human action, not a natural causal relation. Animals connecting thought to object may not count as reference at all. |
14206 | There are infinitely many interpretations of a sentence which can all seem to be 'correct' [Putnam] |
Full Idea: There are always infinitely many different interpretations of the predicates of a language which assign 'correct' truth-values to the sentences in all possible worlds, no matter how those 'correct' truth-values are singled out. | |
From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) | |
A reaction: Putnam says that he is using this argument from model theory to endorse the scepticism about 'gavagai' that Quine expressed in 1960. It is based on the ideas of Skolem, who was a renegade philosopher of mathematics. See Tim Button. |
7624 | The word 'inconsiderate' nicely shows the blurring of facts and values [Putnam] |
Full Idea: The use of the word 'inconsiderate' seems to me a very fine example of the way in which the fact/value distinction is hopelessly fuzzy in the real world and in the real language. | |
From: Hilary Putnam (Reason, Truth and History [1981]) | |
A reaction: Interesting, but not much of an argument. What would Nietzsche say? Was Agamemnon morally deficient because we might think him 'inconsiderate'? |