53 ideas
| 18335 | There are five problems which the truth-maker theory might solve [Rami] |
| Full Idea: It is claimed that truth-makers explain universals, or ontological commitment, or commitment to realism, or to the correspondence theory of truth, or to falsify behaviourism or phenomenalism. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 04) | |
| A reaction: [compressed] This expands the view that truth-making is based on its explanatory power, rather than on its intuitive correctness. I take the theory to presuppose realism. I don't believe in universals. It marginalises correspondence. Commitment is good! |
| 18334 | The truth-maker idea is usually justified by its explanatory power, or intuitive appeal [Rami] |
| Full Idea: The two strategies for justifying the truth-maker principle are that it has an explanatory role (for certain philosophical problems and theses), or that it captures the best philosophical intuition of the situation. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 04) | |
| A reaction: I would go for 'intuitive', but not in the sense of a pure intuition, but with 'intuitive' as a shorthand for overall coherence. To me the appeal of truth-maker is its place in a naturalistic view of reality. I love explanation, but not here. |
| 18339 | The truth-making relation can be one-to-one, or many-to-many [Rami] |
| Full Idea: The truth-making relation can be one-to-one, or many-many. In the latter case, different truths may have the same truth-maker, and one truth may have different truth-makers. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 05) | |
| A reaction: 'There is at least one cat' obviously has many possible truth-makers. Many statements will be made true by the mere existence of a particular cat (such as 'there is an animal in the room' and 'there is a cat in the room'). Many-many wins? |
| 18333 | Central idea: truths need truthmakers; and possibly all truths have them, and makers entail truths [Rami] |
| Full Idea: The main full-blooded truth-maker principle is that x is true iff there is a y that is its truth-maker. This implies the principles that if x is true x has a truth-maker, and the principle that if x has a truth-maker then x is true. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 03) | |
| A reaction: [compressed] Rami calls the second principle 'maximalism' and the third principle 'purism'. To reject maximalism is to hold a more restricted version of truth-makers. That is, the claim is that lots of truths have truth-makers. |
| 18342 | Most theorists say that truth-makers necessitate their truths [Rami] |
| Full Idea: Most truth-maker theorists regard the necessitation of a truth by a truth-maker as a necessary condition of truth-making. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 07) | |
| A reaction: It seems to me that reality is crammed full of potential truth-makers, but not crammed full of truths. If there is no thinking in the universe, then there are no truths. If that is false, then what sort of weird beast is a 'truth'? |
| 18340 | It seems best to assume different kinds of truth-maker, such as objects, facts, tropes, or events [Rami] |
| Full Idea: Truthmaker anti-monism holds the view that there are truth-makers of different kinds. For example, objects, facts, tropes or events can all be regarded as truthmakers. Objects seem right for existential truths but not others, so anti-monism seems best. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 05) | |
| A reaction: Presumably we need to identify the different types of truth (analytic, synthetic, general, particular...), and only then ask what truth-makers there are for the different types. To presuppose one type of truthmaker would be crazy. |
| 18341 | Truth-makers seem to be states of affairs (plus optional individuals), or individuals and properties [Rami] |
| Full Idea: As truth-makers, some theorists only accept states of affairs, some only accept individuals and states of affairs, and some only accept individuals and particular properties. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 06) | |
| A reaction: It seems to me rash to opt for one of these. Truths come in wide-ranging and subtly different types, and the truth-makers probably have a similar range. Any one of these theories will almost certainly quickly succumb to a counterexample. |
| 18346 | 'Truth supervenes on being' only gives necessary (not sufficient) conditions for contingent truths [Rami] |
| Full Idea: The thesis that 'truth supervenes on being' (with or without possible worlds) offers only a necessary condition for the truth of contingent propositions, whereas the standard truth-maker theory offers necessary and sufficient conditions. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 09) | |
| A reaction: The point, I suppose, is that the change in being might be irrelevant to the proposition in question, so any old change in being will not ensure a change in the truth of the proposition. Again we ask - but what is this truth about? |
| 18345 | 'Truth supervenes on being' avoids entities as truth-makers for negative truths [Rami] |
| Full Idea: The important advantage of 'truth supervenes on being' is that it can be applied to positive and negative contingent truths, without postulating any entities that are responsible for the truth of negative truths. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 09) | |
| A reaction: [For this reason, Lewis favours a possible worlds version of the theory] I fear that it solves that problem by making the truth-maker theory so broad-brush that it not longer says very much, apart from committing it to naturalism. |
| 18343 | Maybe a truth-maker also works for the entailments of the given truth [Rami] |
| Full Idea: The 'entailment principle' for truth-makers says that if x is a truth-maker for y, and y entails z, then x is a truth-maker for z. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 08) | |
| A reaction: I think the correct locution is that 'x is a potential truth-maker for z' (should anyone every formulate z, which in most cases they never will, since the entailments of y are probably infinite). Merricks would ask 'but are y and z about the same thing?'. |
| 18338 | Truth-making is usually internalist, but the correspondence theory is externalist [Rami] |
| Full Idea: Most truth-maker theorists are internalists about the truth-maker relation. ...But the correspondence theory makes truth an external relation to some portion of reality. So a truth-maker internalist should not claim to be a narrow correspondence theorist. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 05) | |
| A reaction: [wording rearranged] Like many of Rami's distinctions in this article, this feels simplistic. Sharp distinctions can only be made using sharp vocabulary, and there isn't much of that around in philosophy! |
| 18337 | Correspondence theories assume that truth is a representation relation [Rami] |
| Full Idea: One guiding intuition concerning a correspondence theory of truth says that the relation that accounts for the truth of a truth-bearer is some kind of representation relation. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 05) | |
| A reaction: I unfashionably cling on to some sort of correspondence theory. The paradigm case is of a non-linguistic animal which forms correct or incorrect views about its environment. Truth is a relation, not a property. I see the truth in a bad representation. |
| 18347 | Deflationist truth is an infinitely disjunctive property [Rami] |
| Full Idea: According to the moderate deflationist truth is an infinitely disjunctive property. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 10) | |
| A reaction: [He cites Horwich 1998] That is, I presume, that truth is embodied in an infinity of propositions of the form '"p" is true iff p'. |
| 18350 | Truth-maker theorists should probably reject the converse Barcan formula [Rami] |
| Full Idea: There are good reasons for the truth-maker theorist to reject the converse Barcan formula. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], note 16) | |
| A reaction: In the text (p.15) Rami cites the inference from 'necessarily everything exists' to 'everything exists necessarily'. [See Williamson 1999] |
| 10482 | The logic of ZF is classical first-order predicate logic with identity [Boolos] |
| Full Idea: The logic of ZF Set Theory is classical first-order predicate logic with identity. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.121) | |
| A reaction: This logic seems to be unable to deal with very large cardinals, precisely those that are implied by set theory, so there is some sort of major problem hovering here. Boolos is fairly neutral. |
| 10492 | A few axioms of set theory 'force themselves on us', but most of them don't [Boolos] |
| Full Idea: Maybe the axioms of extensionality and the pair set axiom 'force themselves on us' (Gödel's phrase), but I am not convinced about the axioms of infinity, union, power or replacement. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.130) | |
| A reaction: Boolos is perfectly happy with basic set theory, but rather dubious when very large cardinals come into the picture. |
| 18192 | Do the Replacement Axioms exceed the iterative conception of sets? [Boolos, by Maddy] |
| Full Idea: For Boolos, the Replacement Axioms go beyond the iterative conception. | |
| From: report of George Boolos (The iterative conception of Set [1971]) by Penelope Maddy - Naturalism in Mathematics I.3 |
| 7785 | The use of plurals doesn't commit us to sets; there do not exist individuals and collections [Boolos] |
| Full Idea: We should abandon the idea that the use of plural forms commits us to the existence of sets/classes… Entities are not to be multiplied beyond necessity. There are not two sorts of things in the world, individuals and collections. | |
| From: George Boolos (To be is to be the value of a variable.. [1984]), quoted by Henry Laycock - Object | |
| A reaction: The problem of quantifying over sets is notoriously difficult. Try http://plato.stanford.edu/entries/object/index.html. |
| 10485 | Naïve sets are inconsistent: there is no set for things that do not belong to themselves [Boolos] |
| Full Idea: The naïve view of set theory (that any zero or more things form a set) is natural, but inconsistent: the things that do not belong to themselves are some things that do not form a set. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.127) | |
| A reaction: As clear a summary of Russell's Paradox as you could ever hope for. |
| 10484 | The iterative conception says sets are formed at stages; some are 'earlier', and must be formed first [Boolos] |
| Full Idea: According to the iterative conception, every set is formed at some stage. There is a relation among stages, 'earlier than', which is transitive. A set is formed at a stage if and only if its members are all formed before that stage. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.126) | |
| A reaction: He gives examples of the early stages, and says the conception is supposed to 'justify' Zermelo set theory. It is also supposed to make the axioms 'natural', rather than just being selected for convenience. And it is consistent. |
| 13547 | Limitation of Size is weak (Fs only collect is something the same size does) or strong (fewer Fs than objects) [Boolos, by Potter] |
| Full Idea: Weak Limitation of Size: If there are no more Fs than Gs and the Gs form a collection, then Fs form a collection. Strong Limitation of Size: A property F fails to be collectivising iff there are as many Fs as there are objects. | |
| From: report of George Boolos (Iteration Again [1989]) by Michael Potter - Set Theory and Its Philosophy 13.5 |
| 10699 | Does a bowl of Cheerios contain all its sets and subsets? [Boolos] |
| Full Idea: Is there, in addition to the 200 Cheerios in a bowl, also a set of them all? And what about the vast number of subsets of Cheerios? It is haywire to think that when you have some Cheerios you are eating a set. What you are doing is: eating the Cheerios. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.72) | |
| A reaction: In my case Boolos is preaching to the converted. I am particularly bewildered by someone (i.e. Quine) who believes that innumerable sets exist while 'having a taste for desert landscapes' in their ontology. |
| 14249 | Boolos reinterprets second-order logic as plural logic [Boolos, by Oliver/Smiley] |
| Full Idea: Boolos's conception of plural logic is as a reinterpretation of second-order logic. | |
| From: report of George Boolos (On Second-Order Logic [1975]) by Oliver,A/Smiley,T - What are Sets and What are they For? n5 | |
| A reaction: Oliver and Smiley don't accept this view, and champion plural reference differently (as, I think, some kind of metalinguistic device?). |
| 10225 | Monadic second-order logic might be understood in terms of plural quantifiers [Boolos, by Shapiro] |
| Full Idea: Boolos has proposed an alternative understanding of monadic, second-order logic, in terms of plural quantifiers, which many philosophers have found attractive. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by Stewart Shapiro - Philosophy of Mathematics 3.5 |
| 10830 | Second-order logic metatheory is set-theoretic, and second-order validity has set-theoretic problems [Boolos] |
| Full Idea: The metatheory of second-order logic is hopelessly set-theoretic, and the notion of second-order validity possesses many if not all of the epistemic debilities of the notion of set-theoretic truth. | |
| From: George Boolos (On Second-Order Logic [1975], p.45) | |
| A reaction: Epistemic problems arise when a logic is incomplete, because some of the so-called truths cannot be proved, and hence may be unreachable. This idea indicates Boolos's motivation for developing a theory of plural quantification. |
| 10736 | Boolos showed how plural quantifiers can interpret monadic second-order logic [Boolos, by Linnebo] |
| Full Idea: In an indisputable technical result, Boolos showed how plural quantifiers can be used to interpret monadic second-order logic. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984], Intro) by Øystein Linnebo - Plural Quantification Exposed Intro |
| 10780 | Any sentence of monadic second-order logic can be translated into plural first-order logic [Boolos, by Linnebo] |
| Full Idea: Boolos discovered that any sentence of monadic second-order logic can be translated into plural first-order logic. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984], §1) by Øystein Linnebo - Plural Quantification Exposed p.74 |
| 10829 | A sentence can't be a truth of logic if it asserts the existence of certain sets [Boolos] |
| Full Idea: One may be of the opinion that no sentence ought to be considered as a truth of logic if, no matter how it is interpreted, it asserts that there are sets of certain sorts. | |
| From: George Boolos (On Second-Order Logic [1975], p.44) | |
| A reaction: My intuition is that in no way should any proper logic assert the existence of anything at all. Presumably interpretations can assert the existence of numbers or sets, but we should be able to identify something which is 'pure' logic. Natural deduction? |
| 10697 | Identity is clearly a logical concept, and greatly enhances predicate calculus [Boolos] |
| Full Idea: Indispensable to cross-reference, lacking distinctive content, and pervading thought and discourse, 'identity' is without question a logical concept. Adding it to predicate calculus significantly increases the number and variety of inferences possible. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.54) | |
| A reaction: It is not at all clear to me that identity is a logical concept. Is 'existence' a logical concept? It seems to fit all of Boolos's criteria? I say that all he really means is that it is basic to thought, but I'm not sure it drives the reasoning process. |
| 10832 | '∀x x=x' only means 'everything is identical to itself' if the range of 'everything' is fixed [Boolos] |
| Full Idea: One may say that '∀x x=x' means 'everything is identical to itself', but one must realise that one's answer has a determinate sense only if the reference (range) of 'everything' is fixed. | |
| From: George Boolos (On Second-Order Logic [1975], p.46) | |
| A reaction: This is the problem now discussed in the recent book 'Absolute Generality', of whether one can quantify without specifying a fixed or limited domain. |
| 13671 | Second-order quantifiers are just like plural quantifiers in ordinary language, with no extra ontology [Boolos, by Shapiro] |
| Full Idea: Boolos proposes that second-order quantifiers be regarded as 'plural quantifiers' are in ordinary language, and has developed a semantics along those lines. In this way they introduce no new ontology. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by Stewart Shapiro - Foundations without Foundationalism 7 n32 | |
| A reaction: This presumably has to treat simple predicates and relations as simply groups of objects, rather than having platonic existence, or something. |
| 10267 | We should understand second-order existential quantifiers as plural quantifiers [Boolos, by Shapiro] |
| Full Idea: Standard second-order existential quantifiers pick out a class or a property, but Boolos suggests that they be understood as a plural quantifier, like 'there are objects' or 'there are people'. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by Stewart Shapiro - Philosophy of Mathematics 7.4 | |
| A reaction: This idea has potential application to mathematics, and Lewis (1991, 1993) 'invokes it to develop an eliminative structuralism' (Shapiro). |
| 10698 | Plural forms have no more ontological commitment than to first-order objects [Boolos] |
| Full Idea: Abandon the idea that use of plural forms must always be understood to commit one to the existence of sets of those things to which the corresponding singular forms apply. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.66) | |
| A reaction: It seems to be an open question whether plural quantification is first- or second-order, but it looks as if it is a rewriting of the first-order. |
| 7806 | Boolos invented plural quantification [Boolos, by Benardete,JA] |
| Full Idea: Boolos virtually patented the new device of plural quantification. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by José A. Benardete - Logic and Ontology | |
| A reaction: This would be 'there are some things such that...' |
| 10834 | Weak completeness: if it is valid, it is provable. Strong: it is provable from a set of sentences [Boolos] |
| Full Idea: A weak completeness theorem shows that a sentence is provable whenever it is valid; a strong theorem, that a sentence is provable from a set of sentences whenever it is a logical consequence of the set. | |
| From: George Boolos (On Second-Order Logic [1975], p.52) | |
| A reaction: So the weak version says |- φ → |= φ, and the strong versions says Γ |- φ → Γ |= φ. Presumably it is stronger if it can specify the source of the inference. |
| 13841 | Why should compactness be definitive of logic? [Boolos, by Hacking] |
| Full Idea: Boolos asks why on earth compactness, whatever its virtues, should be definitive of logic itself. | |
| From: report of George Boolos (On Second-Order Logic [1975]) by Ian Hacking - What is Logic? §13 |
| 10491 | Infinite natural numbers is as obvious as infinite sentences in English [Boolos] |
| Full Idea: The existence of infinitely many natural numbers seems to me no more troubling than that of infinitely many computer programs or sentences of English. There is, for example, no longest sentence, since any number of 'very's can be inserted. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.129) | |
| A reaction: If you really resisted an infinity of natural numbers, presumably you would also resist an actual infinity of 'very's. The fact that it is unclear what could ever stop a process doesn't guarantee that the process is actually endless. |
| 10483 | Mathematics and science do not require very high orders of infinity [Boolos] |
| Full Idea: To the best of my knowledge nothing in mathematics or science requires the existence of very high orders of infinity. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.122) | |
| A reaction: He is referring to particular high orders of infinity implied by set theory. Personally I want to wield Ockham's Razor. Is being implied by set theory a sufficient reason to accept such outrageous entities into our ontology? |
| 10833 | Many concepts can only be expressed by second-order logic [Boolos] |
| Full Idea: The notions of infinity and countability can be characterized by second-order sentences, though not by first-order sentences (as compactness and Skolem-Löwenheim theorems show), .. as well as well-ordering, progression, ancestral and identity. | |
| From: George Boolos (On Second-Order Logic [1975], p.48) |
| 10490 | Mathematics isn't surprising, given that we experience many objects as abstract [Boolos] |
| Full Idea: It is no surprise that we should be able to reason mathematically about many of the things we experience, for they are already 'abstract'. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.129) | |
| A reaction: He has just given a list of exemplary abstract objects (Idea 10489), but I think there is a more interesting idea here - that our experience of actual physical objects is to some extent abstract, as soon as it is conceptualised. |
| 10700 | First- and second-order quantifiers are two ways of referring to the same things [Boolos] |
| Full Idea: Ontological commitment is carried by first-order quantifiers; a second-order quantifier needn't be taken to be a first-order quantifier in disguise, having special items, collections, as its range. They are two ways of referring to the same things. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.72) | |
| A reaction: If second-order quantifiers are just a way of referring, then we can see first-order quantifiers that way too, so we could deny 'objects'. |
| 18336 | Internal relations depend either on the existence of the relata, or on their properties [Rami] |
| Full Idea: An internal relation is 'existential' if x and y relate in that way whenever they both exist. An internal relation is 'qualitative' if x and y relate in that way whenever they have certain intrinsic properties. | |
| From: Adolph Rami (Introduction: Truth and Truth-Making [2009], 05) | |
| A reaction: [compressed - Rami likes to write these things in fashionable quasi-algebra, but I have a strong prejudice in this database for expressing ideas in English; call me old-fashioned] The distinction strikes me as simplistic. I would involve dispositions. |
| 10488 | It is lunacy to think we only see ink-marks, and not word-types [Boolos] |
| Full Idea: It's a kind of lunacy to think that sound scientific philosophy demands that we think that we see ink-tracks but not words, i.e. word-types. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.128) | |
| A reaction: This seems to link him with Armstrong's mockery of 'ostrich nominalism'. There seems to be some ambiguity with the word 'see' in this disagreement. When we look at very ancient scratches on stones, why don't we always 'see' if it is words? |
| 10487 | I am a fan of abstract objects, and confident of their existence [Boolos] |
| Full Idea: I am rather a fan of abstract objects, and confident of their existence. Smaller numbers, sets and functions don't offend my sense of reality. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.128) | |
| A reaction: The great Boolos is rather hard to disagree with, but I disagree. Logicians love abstract objects, indeed they would almost be out of a job without them. It seems to me they smuggle them into our ontology by redefining either 'object' or 'exists'. |
| 10489 | We deal with abstract objects all the time: software, poems, mistakes, triangles.. [Boolos] |
| Full Idea: We twentieth century city dwellers deal with abstract objects all the time, such as bank balances, radio programs, software, newspaper articles, poems, mistakes, triangles. | |
| From: George Boolos (Must We Believe in Set Theory? [1997], p.129) | |
| A reaction: I find this claim to be totally question-begging, and typical of a logician. The word 'object' gets horribly stretched in these discussions. We can create concepts which have all the logical properties of objects. Maybe they just 'subsist'? |
| 10938 | The extremes of essentialism are that all properties are essential, or only very trivial ones [Rami] |
| Full Idea: It would be natural to label one extreme view 'maximal essentialism' - that all of an object's properties are essential - and the other extreme 'minimal' - that only trivial properties such as self-identity of being either F or not-F are essential. | |
| From: Adolph Rami (Essential vs Accidental Properties [2008]) | |
| A reaction: Personally I don't accept the trivial ones as being in any way describable as 'properties'. The maximal view destroys any useful notion of essence. Leibniz is a minority holder of the maximal view. I would defend a middle way. |
| 10940 | An 'individual essence' is possessed uniquely by a particular object [Rami] |
| Full Idea: An 'individual essence' is a property that in addition to being essential is also unique to the object, in the sense that it is not possible that something distinct from that object possesses that property. | |
| From: Adolph Rami (Essential vs Accidental Properties [2008], §5) | |
| A reaction: She cites a 'haecceity' (or mere bare identity) as a trivial example of an individual essence. |
| 10939 | 'Sortal essentialism' says being a particular kind is what is essential [Rami] |
| Full Idea: According to 'sortal essentialism', an object could not have been of a radically different kind than it in fact is. | |
| From: Adolph Rami (Essential vs Accidental Properties [2008], §4) | |
| A reaction: This strikes me as thoroughly wrong. Things belong in kinds because of their properties. Could you remove all the contingent features of a tiger, leaving it as merely 'a tiger', despite being totally unrecognisable? |
| 10934 | Unlosable properties are not the same as essential properties [Rami] |
| Full Idea: It is easy to confuse the notion of an essential property that a thing could not lack, with a property it could not lose. My having spent Christmas 2007 in Tennessee is a non-essential property I could not lose. | |
| From: Adolph Rami (Essential vs Accidental Properties [2008], §1) | |
| A reaction: The idea that having spent Christmas in Tennessee is a property I find quite bewildering. Is my not having spent my Christmas in Tennessee one of my properties? I suspect that real unlosable properties are essential ones. |
| 10933 | Physical possibility is part of metaphysical possibility which is part of logical possibility [Rami] |
| Full Idea: The usual view is that 'physical possibilities' are a natural subset of the 'metaphysical possibilities', which in turn are a subset of the 'logical possibilities'. | |
| From: Adolph Rami (Essential vs Accidental Properties [2008], §1) | |
| A reaction: [She cites Fine 2002 for an opposing view] I prefer 'natural' to 'physical', leaving it open where the borders of the natural lie. I take 'metaphysical' possibility to be 'in all naturally possible worlds'. So is a round square a logical possibility? |
| 10932 | If it is possible 'for all I know' then it is 'epistemically possible' [Rami] |
| Full Idea: There is 'epistemic possibility' when it is 'for all I know'. That is, P is epistemically possible for agent A just in case P is consistent with what A knows. | |
| From: Adolph Rami (Essential vs Accidental Properties [2008], §1) | |
| A reaction: Two problems: maybe 'we' know, and A knows we know, but A doesn't know. And maybe someone knows, but we are not sure about that, which seems to introduce a modal element into the knowing. If someone knows it's impossible, it's impossible. |
| 8693 | An 'abstraction principle' says two things are identical if they are 'equivalent' in some respect [Boolos] |
| Full Idea: Hume's Principle has a structure Boolos calls an 'abstraction principle'. Within the scope of two universal quantifiers, a biconditional connects an identity between two things and an equivalence relation. It says we don't care about other differences. | |
| From: George Boolos (Is Hume's Principle analytic? [1997]), quoted by Michèle Friend - Introducing the Philosophy of Mathematics 3.7 | |
| A reaction: This seems to be the traditional principle of abstraction by ignoring some properties, but dressed up in the clothes of formal logic. Frege tries to eliminate psychology, but Boolos implies that what we 'care about' is relevant. |
| 6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |
| Full Idea: Hermarchus said that animal killing is justified by considerations of human safety and nourishment and by animals' inability to form contractual relations of justice with us. | |
| From: report of Hermarchus (fragments/reports [c.270 BCE]) by David A. Sedley - Hermarchus | |
| A reaction: Could the last argument be used to justify torturing animals? Or could we eat a human who was too brain-damaged to form contracts? |