50 ideas
6267 | A culture needs to admit that knowledge is more extensive than just 'science' [Putnam] |
Full Idea: The acknowledgement that the sphere of knowledge is wider than the sphere of 'science' seems to me to be a cultural necessity if we are to arrive at a sane and human view of ourselves or of science. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Intro) | |
A reaction: A very nice remark, with which I intuitively agree, but then you are left with the problem of explaining how something can qualify as knowledge when it can't pass the stringent tests of science. How wide to we spread, and why? |
6272 | 'True' and 'refers' cannot be made scientically precise, but are fundamental to science [Putnam] |
Full Idea: Some non-scientific knowledge is presupposed by science; for example, I have been arguing that 'refers' and 'true' cannot be made scientifically precise; yet truth is a fundamental term in logic - a precise science. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Lec VI) | |
A reaction: We might ask whether we 'know' what 'true' and 'refers' mean, as opposed to being able to use them. If their usage doesn't count as knowledge, then we could still end up with all actual knowledge being somehow 'scientific'. |
6276 | 'The rug is green' might be warrantedly assertible even though the rug is not green [Putnam] |
Full Idea: 'The rug is green' might be warrantedly assertible even though the rug is not green. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Three) | |
A reaction: The word 'warranted' seems to be ambiguous in modern philosophy. See Idea 6150. There seem to be internalist and externalist versions. It seems clear to say that a belief could be well-justified and yet false. |
6266 | We need the correspondence theory of truth to understand language and science [Putnam] |
Full Idea: A correspondence theory of truth is needed to understand how language works, and how science works. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Intro) | |
A reaction: Putnam retreated from this position to a more pragmatic one later on, but all my sympathies are with the present view, despite being repeatedly told by modern philosophers that I am wrong. See McGinn (Idea 6085) and Searle (Idea 3508). |
6277 | Correspondence between concepts and unconceptualised reality is impossible [Putnam] |
Full Idea: The great nineteenth century argument against the correspondence theory of truth was that one cannot think of truth as correspondence to facts (or 'reality') because one would need to compare concepts directly with unconceptualised reality. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Three) | |
A reaction: Presumably the criticism was offered by idealists, who preferred a coherence theory. The defence is to say that there is a confusion here between a concept and the contents of a concept. The contents of a concept are designed to be facts. |
6264 | In Tarski's definition, you understand 'true' if you accept the notions of the object language [Putnam] |
Full Idea: Anyone who accepts the notions of whatever object language is in question - and this can be chosen arbitrarily - can also understand 'true' as defined by Tarski for that object language. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Intro) | |
A reaction: Thus if we say "'snow is white' is true iff snow is white", then if you 'accept the notion' that snow is white in English, you understand what 'true' means. This seems to leave you with the meaning of 'snow is white' being its truth conditions. |
6265 | Tarski has given a correct account of the formal logic of 'true', but there is more to the concept [Putnam] |
Full Idea: What Tarski has done is to give us a perfectly correct account of the formal logic of the concept 'true', but the formal logic of the concept is not all there is to the notion of truth. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Intro) | |
A reaction: I find this refreshing. A lot of modern philosophers seem to think that truth is no longer an interesting philosophical topic, because deflationary accounts have sidelined it, but I take the concept to be at the heart of metaphysics. |
6269 | Only Tarski has found a way to define 'true' [Putnam] |
Full Idea: There is only one way anyone knows how to define 'true' and that is Tarski's way. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Lec II.5) | |
A reaction: However, Davidson wrote a paper called 'On the Folly of Trying to Define Truth', which seems to reject even Tarski. Also bear in mind Putnam's earlier remark (Idea 6265) that there is more to truth than Tarski's definition. Just take 'true' as primitive. |
18194 | 'Forcing' can produce new models of ZFC from old models [Maddy] |
Full Idea: Cohen's method of 'forcing' produces a new model of ZFC from an old model by appending a carefully chosen 'generic' set. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.4) |
18195 | A Large Cardinal Axiom would assert ever-increasing stages in the hierarchy [Maddy] |
Full Idea: A possible axiom is the Large Cardinal Axiom, which asserts that there are more and more stages in the cumulative hierarchy. Infinity can be seen as the first of these stages, and Replacement pushes further in this direction. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.5) |
18191 | Axiom of Infinity: completed infinite collections can be treated mathematically [Maddy] |
Full Idea: The axiom of infinity: that there are infinite sets is to claim that completed infinite collections can be treated mathematically. In its standard contemporary form, the axioms assert the existence of the set of all finite ordinals. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.3) |
18193 | The Axiom of Foundation says every set exists at a level in the set hierarchy [Maddy] |
Full Idea: In the presence of other axioms, the Axiom of Foundation is equivalent to the claim that every set is a member of some Vα. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.3) |
18169 | Axiom of Reducibility: propositional functions are extensionally predicative [Maddy] |
Full Idea: The Axiom of Reducibility states that every propositional function is extensionally equivalent to some predicative proposition function. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.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'. |
18171 | Cantor and Dedekind brought completed infinities into mathematics [Maddy] |
Full Idea: Both Cantor's real number (Cauchy sequences of rationals) and Dedekind's cuts involved regarding infinite items (sequences or sets) as completed and subject to further manipulation, bringing the completed infinite into mathematics unambiguously. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.1 n39) | |
A reaction: So it is the arrival of the real numbers which is the culprit for lumbering us with weird completed infinites, which can then be the subject of addition, multiplication and exponentiation. Maybe this was a silly mistake? |
18190 | Completed infinities resulted from giving foundations to calculus [Maddy] |
Full Idea: The line of development that finally led to a coherent foundation for the calculus also led to the explicit introduction of completed infinities: each real number is identified with an infinite collection of rationals. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.3) | |
A reaction: Effectively, completed infinities just are the real numbers. |
18172 | Infinity has degrees, and large cardinals are the heart of set theory [Maddy] |
Full Idea: The stunning discovery that infinity comes in different degrees led to the theory of infinite cardinal numbers, the heart of contemporary set theory. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.1) | |
A reaction: It occurs to me that these huge cardinals only exist in set theory. If you took away that prop, they would vanish in a puff. |
18175 | For any cardinal there is always a larger one (so there is no set of all sets) [Maddy] |
Full Idea: By the mid 1890s Cantor was aware that there could be no set of all sets, as its cardinal number would have to be the largest cardinal number, while his own theorem shows that for any cardinal there is a larger. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.1) | |
A reaction: There is always a larger cardinal because of the power set axiom. Some people regard that with suspicion. |
18196 | An 'inaccessible' cardinal cannot be reached by union sets or power sets [Maddy] |
Full Idea: An 'inaccessible' cardinal is one that cannot be reached by taking unions of small collections of smaller sets or by taking power sets. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.5) | |
A reaction: They were introduced by Hausdorff in 1908. |
18187 | Theorems about limits could only be proved once the real numbers were understood [Maddy] |
Full Idea: Even the fundamental theorems about limits could not [at first] be proved because the reals themselves were not well understood. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.2) | |
A reaction: This refers to the period of about 1850 (Weierstrass) to 1880 (Dedekind and Cantor). |
18182 | The extension of concepts is not important to me [Maddy] |
Full Idea: I attach no decisive importance even to bringing in the extension of the concepts at all. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], §107) | |
A reaction: He almost seems to equate the concept with its extension, but that seems to raise all sorts of questions, about indeterminate and fluctuating extensions. |
18177 | In the ZFC hierarchy it is impossible to form Frege's set of all three-element sets [Maddy] |
Full Idea: In the ZFC cumulative hierarchy, Frege's candidates for numbers do not exist. For example, new three-element sets are formed at every stage, so there is no stage at which the set of all three-element sets could he formed. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.2) | |
A reaction: Ah. This is a very important fact indeed if you are trying to understand contemporary discussions in philosophy of mathematics. |
18164 | Frege solves the Caesar problem by explicitly defining each number [Maddy] |
Full Idea: To solve the Julius Caesar problem, Frege requires explicit definitions of the numbers, and he proposes his well-known solution: the number of Fs = the extension of the concept 'equinumerous with F' (based on one-one correspondence). | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.1) | |
A reaction: Why do there have to be Fs before there can be the corresponding number? If there were no F for 523, would that mean that '523' didn't exist (even if 522 and 524 did exist)? |
18184 | Making set theory foundational to mathematics leads to very fruitful axioms [Maddy] |
Full Idea: The set theory axioms developed in producing foundations for mathematics also have strong consequences for existing fields, and produce a theory that is immensely fruitful in its own right. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.2) | |
A reaction: [compressed] Second of Maddy's three benefits of set theory. This benefit is more questionable than the first, because the axioms may be invented because of their nice fruit, instead of their accurate account of foundations. |
18185 | Unified set theory gives a final court of appeal for mathematics [Maddy] |
Full Idea: The single unified area of set theory provides a court of final appeal for questions of mathematical existence and proof. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.2) | |
A reaction: Maddy's third benefit of set theory. 'Existence' means being modellable in sets, and 'proof' means being derivable from the axioms. The slightly ad hoc character of the axioms makes this a weaker defence. |
18183 | Set theory brings mathematics into one arena, where interrelations become clearer [Maddy] |
Full Idea: Set theoretic foundations bring all mathematical objects and structures into one arena, allowing relations and interactions between them to be clearly displayed and investigated. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.2) | |
A reaction: The first of three benefits of set theory which Maddy lists. The advantages of the one arena seem to be indisputable. |
18186 | Identifying geometric points with real numbers revealed the power of set theory [Maddy] |
Full Idea: The identification of geometric points with real numbers was among the first and most dramatic examples of the power of set theoretic foundations. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.2) | |
A reaction: Hence the clear definition of the reals by Dedekind and Cantor was the real trigger for launching set theory. |
18188 | The line of rationals has gaps, but set theory provided an ordered continuum [Maddy] |
Full Idea: The structure of a geometric line by rational points left gaps, which were inconsistent with a continuous line. Set theory provided an ordering that contained no gaps. These reals are constructed from rationals, which come from integers and naturals. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.2) | |
A reaction: This completes the reduction of geometry to arithmetic and algebra, which was launch 250 years earlier by Descartes. |
18163 | Mathematics rests on the logic of proofs, and on the set theoretic axioms [Maddy] |
Full Idea: Our much loved mathematical knowledge rests on two supports: inexorable deductive logic (the stuff of proof), and the set theoretic axioms. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I Intro) |
18207 | Maybe applications of continuum mathematics are all idealisations [Maddy] |
Full Idea: It could turn out that all applications of continuum mathematics in natural sciences are actually instances of idealisation. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], II.6) |
18204 | Scientists posit as few entities as possible, but set theorist posit as many as possible [Maddy] |
Full Idea: Crudely, the scientist posits only those entities without which she cannot account for observations, while the set theorist posits as many entities as she can, short of inconsistency. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], II.5) |
18167 | We can get arithmetic directly from HP; Law V was used to get HP from the definition of number [Maddy] |
Full Idea: Recent commentators have noted that Frege's versions of the basic propositions of arithmetic can be derived from Hume's Principle alone, that the fatal Law V is only needed to derive Hume's Principle itself from the definition of number. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], I.1) | |
A reaction: Crispin Wright is the famous exponent of this modern view. Apparently Charles Parsons (1965) first floated the idea. |
6280 | Realism is a theory, which explains the convergence of science and the success of language [Putnam] |
Full Idea: Realism is an empirical theory; it explains the convergence of scientific theories, where earlier theories are often limiting cases of later theories (which is why theoretical terms preserve their reference); and it explains the success of language. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Four) | |
A reaction: I agree. Personally, I think of Plato's Theory of Forms and all religions as empirical theories. The response from anti-realists is generally to undermine confidence in the evidence which these 'empirical theories' are said to explain. |
18205 | The theoretical indispensability of atoms did not at first convince scientists that they were real [Maddy] |
Full Idea: The case of atoms makes it clear that the indispensable appearance of an entity in our best scientific theory is not generally enough to convince scientists that it is real. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], II.6) | |
A reaction: She refers to the period between Dalton and Einstein, when theories were full of atoms, but there was strong reluctance to actually say that they existed, until the direct evidence was incontrovertable. Nice point. |
14798 | All communication is vague, and is outside the principle of non-contradiction [Peirce] |
Full Idea: The 'vague' might be defined as that to which the principle of contradiction does not apply. For it is false neither that an animal (in a vague sense) is male, nor that an animal is female. No communication between persons can be entirely non-vague. | |
From: Charles Sanders Peirce (Critical Common-Sensism [1905], I) | |
A reaction: Note that he makes vagueness largely a matter of the way we talk, which is David Lewis's approach, and looks right to me. |
14797 | Vagueness is a neglected but important part of mathematical thought [Peirce] |
Full Idea: Logicians have too much neglected the study of vagueness, not suspecting the important part it plays in mathematical thought. It is the antithetical analogue of generality. | |
From: Charles Sanders Peirce (Critical Common-Sensism [1905], I) |
6284 | If a tautology is immune from revision, why would that make it true? [Putnam] |
Full Idea: If we held, say, 'All unmarried men are unmarried' as absolutely immune from revision, why would this make it true? | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Four) | |
A reaction: A very nice question. Like most American philosophers, Putnam accepts Quine's attack on the unrevisability of analytic truths. His point here is that defenders of analytic truths are probably desperate to preserve basic truths, but it won't work. |
6273 | Knowledge depends on believing others, which must be innate, as inferences are not strong enough [Putnam] |
Full Idea: Our ability to picture how people are likely to respond may well be innate; indeed, our disposition to believe what other people tell us (which is fundamental to knowledge) could hardly be an inference, as that isn’t good enough for knowledge. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Lec VI) | |
A reaction: An interesting claim. There could be an intermediate situation, which is a hard-wired non-conscious inference. When dismantled, the 'innate' brain circuits for assessing testimony could turn out to work on logic and evidence. |
6274 | Empathy may not give knowledge, but it can give plausibility or right opinion [Putnam] |
Full Idea: Empathy with others may give less than 'Knowledge', but it gives more than mere logical or physical possibility; it gives plausibility, or (to revive Platonic terminology) it provides 'right opinion'. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Lec VI) | |
A reaction: See Ideas 174 and 2140 for Plato. Putnam is exploring areas of knowledge outside the limits of strict science. Behind this claim seems to lie the Principle of Charity (3971), but a gang of systematic liars (e.g. evil students) would be a problem case. |
17084 | You can't decide which explanations are good if you don't attend to the interest-relative aspects [Putnam] |
Full Idea: Explanation is an interest-relative notion …explanation has to be partly a pragmatic concept. To regard the 'pragmatics' of explanation as no part of the concept is to abdicate the job of figuring out what makes an explanation good. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], p. 41-2), quoted by David-Hillel Ruben - Explaining Explanation Ch 1 | |
A reaction: I suppose this is just obvious, depending on how far you want to take the 'interest-relative' bit. If a fool is fobbed off with a trivial explanation, there must be some non-relative criterion for assessing that. |
18206 | Science idealises the earth's surface, the oceans, continuities, and liquids [Maddy] |
Full Idea: In science we treat the earth's surface as flat, we assume the ocean to be infinitely deep, we use continuous functions for what we know to be quantised, and we take liquids to be continuous despite atomic theory. | |
From: Penelope Maddy (Naturalism in Mathematics [1997], II.6) | |
A reaction: If fussy people like scientists do this all the time, how much more so must the confused multitude be doing the same thing all day? |
6282 | Theory of meaning presupposes theory of understanding and reference [Putnam] |
Full Idea: Theory of meaning presupposes theory of understanding and reference. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Four) | |
A reaction: How can you have a theory of understanding without a meaning that requires to be understood? Personally I think about the minds of small animals when pondering this, and that seems to put reference and truth at the front of the queue. |
6281 | Truth conditions can't explain understanding a sentence, because that in turn needs explanation [Putnam] |
Full Idea: You can't treat understanding a sentence as knowing its truth conditions, because it then becomes unintelligible what that knowledge in turn consists in. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Four) | |
A reaction: The implication, I take it, is circularity; how can you specify truth conditions if you don't understand sentences? Putnam here agrees with Dummett that verification must be involved. Something has to be taken as axiomatic in all this. |
6278 | We should reject the view that truth is prior to meaning [Putnam] |
Full Idea: I am suggesting that we reject the view that truth (based on the semantic theory) is prior to meaning. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Three) | |
A reaction: It is a nice question which of truth or meaning has logical priority. One might start by speculating about how and why animals think. A moth attracted to flame is probably working on truth without much that could be called 'meaning'. |
6271 | How reference is specified is not what reference is [Putnam] |
Full Idea: A theory of how reference is specified isn't a theory of what reference is. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Lec V) | |
A reaction: A simple and important point. We may achieve reference by naming, describing, grunting or pointing, but the question is, what have we achieved when we get there? |
6268 | The claim that scientific terms are incommensurable can be blocked if scientific terms are not descriptions [Putnam] |
Full Idea: The line of reasoning of Kuhn and Feyerabend can be blocked by arguing (as I have in various places, and as Saul Kripke has) that scientific terms are not synonymous with descriptions. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Lec II.2) | |
A reaction: A nice clear statement of the motivation for creating the causal theory of reference. See Idea 6162. We could still go back and ask whether we could block scientific relativism by rethinking how descriptions work, instead of abandoning them. |
6279 | A private language could work with reference and beliefs, and wouldn't need meaning [Putnam] |
Full Idea: A language made up and used by a being who belonged to no community would have no need for such a concept as the 'meaning' of a term. To state the reference of each term and what the language speaker believes is to tell the whole story. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Three) | |
A reaction: A subtle response to Wittgenstein's claim (e.g. Ideas 4152,4158), but I am not sure what Putnam means. I would have thought that beliefs had to be embodied in propositions. They may not need 'meaning' quite as urgently as sentences, but still… |
6270 | The correct translation is the one that explains the speaker's behaviour [Putnam] |
Full Idea: What it is to be a correct translation is to be the translation that best explains the behaviour of the speaker. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Lec III) | |
A reaction: This seems fairly close to Quine, but rather puzzlingly uses the word 'correct'. If our criteria of translation are purely behavioural, there is no way we can be correct after one word ('gavagai'), so at what point does it become 'correct'? |
6283 | Language maps the world in many ways (because it maps onto other languages in many ways) [Putnam] |
Full Idea: We could say that the language has more than one correct way of being mapped onto the world (it must, since it has more than one way of being correctly mapped onto a language which is itself correctly mapped onto the world). | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Four) | |
A reaction: This spells out nicely the significance of Quine's 'indeterminacy of translation'. Others have pointed out that the fact that language maps onto world in many ways need not be anti-realist; the world is endless, and language is limited. |
6275 | You can't say 'most speaker's beliefs are true'; in some areas this is not so, and you can't count beliefs [Putnam] |
Full Idea: The maxim that 'most of a speaker's beliefs are true' as an a priori principle governing radical translation seems to me to go too far; first, I don't know how to count beliefs; second, most people's beliefs on some topics (philosophy) are probably false. | |
From: Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Three) | |
A reaction: Putnam prefers a pragmatic view, where charity is applicable if behaviour is involved. Philosophy is too purely theoretical. The extent to which Charity should apply in philosophy seminars is a nice question, which all students should test in practice. |