73 ideas
| 18835 | Logic doesn't have a metaphysical basis, but nor can logic give rise to the metaphysics [Rumfitt] |
| Full Idea: There is surely no metaphysical basis for logic, but equally there is no logical basis for metaphysics, if that implies that we can settle the choice of logic in advance of settling any seriously contested metaphysical-cum-semantic issues. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 7.5) | |
| A reaction: Is this aimed at Tim Williamson's book on treating modal logic as metaphysics? I agree with the general idea that logic won't deliver a metaphysics. I might want to defend a good metaphysics giving rise to a good logic. |
| 18819 | The idea that there are unrecognised truths is basic to our concept of truth [Rumfitt] |
| Full Idea: The realist principle that a statement may be true even though no one is able to recognise its truth is so deeply embedded in our ordinary conception of truth that any account that flouts it is liable to engender confusion. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 5.1) |
| 18826 | 'True at a possibility' means necessarily true if what is said had obtained [Rumfitt] |
| Full Idea: A statement is 'true at a possibility' if, necessarily, things would have been as the statement (actually) says they are, had the possibility obtained. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 6.6) | |
| A reaction: This is deliberately vague about what a 'possibility' is, but it is intended to be more than a property instantiation, and less than a possible world. |
| 18803 | Semantics for propositions: 1) validity preserves truth 2) non-contradition 3) bivalence 4) truth tables [Rumfitt] |
| Full Idea: The classical semantics of natural language propositions says 1) valid arguments preserve truth, 2) no statement is both true and false, 3) each statement is either true or false, 4) the familiar truth tables. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) |
| 18814 | 'Absolute necessity' would have to rest on S5 [Rumfitt] |
| Full Idea: If there is such a notion as 'absolute necessity', its logic is surely S5. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 3.3) | |
| A reaction: There are plenty of people (mainly in the strict empiricist tradition) who don't believe in 'absolute' necessity. |
| 18798 | It is the second-order part of intuitionistic logic which actually negates some classical theorems [Rumfitt] |
| Full Idea: Although intuitionistic propositional and first-order logics are sub-systems of the corresponding classical systems, intuitionistic second-order logic affirms the negations of some classical theorems. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) |
| 18799 | Intuitionists can accept Double Negation Elimination for decidable propositions [Rumfitt] |
| Full Idea: Double Negation Elimination is a rule of inference which the classicist accepts without restriction, but which the intuitionist accepts only for decidable propositions. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) | |
| A reaction: This cures me of my simplistic understanding that intuitionists just reject the rules about double negation. |
| 18830 | Most set theorists doubt bivalence for the Continuum Hypothesis, but still use classical logic [Rumfitt] |
| Full Idea: Many set theorists doubt if the Generalised Continuum Hypothesis must be either true or false; certainly, its bivalence is far from obvious. All the same, almost all set theorists use classical logic in their proofs. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 7.2) | |
| A reaction: His point is that classical logic is usually taken to rest on bivalence. He offers the set theorists a helping hand, by defending classical logic without resorting to bivalence. |
| 18843 | The iterated conception of set requires continual increase in axiom strength [Rumfitt] |
| Full Idea: We are doomed to postulate an infinite sequence of successively stronger axiom systems as we try to spell out what is involved in iterating the power set operation 'as far as possible'. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 9.3) | |
| A reaction: [W.W. Tait is behind this idea] The problem with set theory, then, especially as a foundation of mathematics, is that it doesn't just expand, but has to keep reinventing itself. The 'large cardinal axioms' are what is referred to. |
| 18836 | A set may well not consist of its members; the empty set, for example, is a problem [Rumfitt] |
| Full Idea: There seem strong grounds for rejecting the thesis that a set consists of its members. For one thing, the empty set is a perpetual embarrassment for the thesis. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 8.4) | |
| A reaction: Rumfitt also says that if 'red' has an extension, then membership of that set must be vague. Extensional sets are precise because their objects are decided in advance, but intensional (or logical) sets, decided by a predicate, can be vague. |
| 18837 | A set can be determinate, because of its concept, and still have vague membership [Rumfitt] |
| Full Idea: Vagueness in respect of membership is consistent with determinacy of the set's identity, so long as a set's identity is taken to consist, not in its having such-and-such members, but in its being the extension of the concept A. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 8.4) | |
| A reaction: To be determinate, it must be presumed that there is some test which will decide what falls under the concept. The rule can say 'if it is vague, reject it' or 'if it is vague, accept it'. Without one of those, how could the set have a clear identity? |
| 18845 | If the totality of sets is not well-defined, there must be doubt about the Power Set Axiom [Rumfitt] |
| Full Idea: Someone who is sympathetic to the thesis that the totality of sets is not well-defined ought to concede that we have no reason to think that the Power Set Axiom is true. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 9.6) | |
| A reaction: The point is that it is only this Axiom which generates the vast and expanding totality. In principle it is hard, though, to see what is intrinsically wrong with the operation of taking the power set of a set. Hence 'limitation of size'? |
| 18815 | Logic is higher-order laws which can expand the range of any sort of deduction [Rumfitt] |
| Full Idea: On the conception of logic recommended here, logical laws are higher-order laws that can be applied to expand the range of any deductive principles. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 3.3) | |
| A reaction: You need the concept of a 'deductive principle' to get this going, but I take it that might be directly known, rather than derived from a law. |
| 18805 | Classical logic rules cannot be proved, but various lines of attack can be repelled [Rumfitt] |
| Full Idea: There is not the slightest prospect of proving that the rules of classical logic are sound. ….All that the defender of classical logic can do is scrutinize particular attacks and try to repel them. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) | |
| A reaction: This is the agenda for Rumfitt's book. |
| 18804 | The case for classical logic rests on its rules, much more than on the Principle of Bivalence [Rumfitt] |
| Full Idea: I think it is a strategic mistake to rest the case for classical logic on the Principle of Bivalence: the soundness of the classical logic rules is far more compelling than the truth of Bivalence. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) | |
| A reaction: The 'rules' to which he is referring are those of 'natural deduction', which make very few assumptions, and are intended to be intuitively appealing. |
| 18827 | If truth-tables specify the connectives, classical logic must rely on Bivalence [Rumfitt] |
| Full Idea: If we specify the senses of the connectives by way of the standard truth-tables, then we must justify classical logic only by appeal to the Principle of Bivalence. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 7) | |
| A reaction: Rumfitt proposes to avoid the truth-tables, and hence not to rely on Bivalence for his support of classical logic. He accepts that Bivalence is doubtful, citing the undecidability of the Continuum Hypothesis as a problem instance. |
| 18813 | Logical consequence is a relation that can extended into further statements [Rumfitt] |
| Full Idea: Logical consequence, I argue, is distinguished from other implication relations by the fact that logical laws may be applied in extending any implication relation so that it applies among some complex statements involving logical connectives. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 3.3) | |
| A reaction: He offers implication in electronics as an example of a non-logical implication relation. This seems to indicate that logic must be monotonic, that consequence is transitive, and that the Cut Law always applies. |
| 18808 | Normal deduction presupposes the Cut Law [Rumfitt] |
| Full Idea: Our deductive practices seem to presuppose the Cut Law. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 2.3) | |
| A reaction: That is, if you don't believe that deductions can be transitive (and thus form a successful chain of implications), then you don't really believe in deduction. It remains a well known fact that you can live without the Cut Law. |
| 18840 | When faced with vague statements, Bivalence is not a compelling principle [Rumfitt] |
| Full Idea: I do not regard Bivalence, when applied to vague statements, as an intuitively compelling principle which we ought to try to preserve. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 8.7) | |
| A reaction: The point of Rumfitt's book is to defend classical logic despite failures of bivalence. He also cites undecidable concepts such as the Continuum Hypothesis. |
| 18802 | In specifying a logical constant, use of that constant is quite unavoidable [Rumfitt] |
| Full Idea: There is no prospect whatever of giving the sense of a logical constant without using that very constant, and much else besides, in the metalinguistic principle that specifies that sense. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) |
| 18800 | Introduction rules give deduction conditions, and Elimination says what can be deduced [Rumfitt] |
| Full Idea: 'Introduction rules' state the conditions under which one may deduce a conclusion whose dominant logical operator is the connective. 'Elimination rules' state what may be deduced from some premises, where the major premise is dominated by the connective. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) | |
| A reaction: So Introduction gives conditions for deduction, and Elimination says what can actually be deduced. If my magic wand can turn you into a frog (introduction), and so I turn you into a frog, how does that 'eliminate' the wand? |
| 18809 | Logical truths are just the assumption-free by-products of logical rules [Rumfitt] |
| Full Idea: Gentzen's way of formalising logic has accustomed people to the idea that logical truths are simply the by-products of logical rules, that arise when all the assumptions on which a conclusion rests have been discharged. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 2.5) | |
| A reaction: This is the key belief of those who favour the natural deduction account of logic. If you really believe in separate logic truths, then you can use them as axioms. |
| 18807 | Monotonicity means there is a guarantee, rather than mere inductive support [Rumfitt] |
| Full Idea: Monotonicity seems to mark the difference between cases in which a guarantee obtains and those where the premises merely provide inductive support for a conclusion. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 2.3) | |
| A reaction: Hence it is plausible to claim that 'non-monotonic logic' is a contradiction in terms. |
| 18842 | Maybe an ordinal is a property of isomorphic well-ordered sets, and not itself a set [Rumfitt] |
| Full Idea: Menzel proposes that an ordinal is something isomorphic well-ordered sets have in common, so while an ordinal can be represented as a set, it is not itself a set, but a 'property' of well-ordered sets. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 9.2) | |
| A reaction: [C.Menzel 1986] This is one of many manoeuvres available if you want to distance mathematics from set theory. |
| 18834 | Infinitesimals do not stand in a determinate order relation to zero [Rumfitt] |
| Full Idea: Infinitesimals do not stand in a determinate order relation to zero: we cannot say an infinitesimal is either less than zero, identical to zero, or greater than zero. ….Infinitesimals are so close to zero as to be theoretically indiscriminable from it. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 7.4) |
| 18846 | Cantor and Dedekind aimed to give analysis a foundation in set theory (rather than geometry) [Rumfitt] |
| Full Idea: One of the motivations behind Cantor's and Dedekind's pioneering explorations in the field was the ambition to give real analysis a new foundation in set theory - and hence a foundation independent of geometry. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 9.6) | |
| A reaction: Rumfitt is inclined to think that the project has failed, although a weaker set theory than ZF might do the job (within limits). |
| 3942 | I do not believe in the existence of anything, if I see no reason to believe it [Berkeley] |
| Full Idea: It is to me a sufficient reason not to believe the existence of anything, if I see no reason for believing it. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.205) | |
| A reaction: This may just be a reasonable application of Ockham's Razor, but I fear that Berkeley painted himself into corner by demanding too many 'reasons' for everything. |
| 3952 | I know that nothing inconsistent can exist [Berkeley] |
| Full Idea: I know that nothing inconsistent can exist. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.224) | |
| A reaction: Fine, but the problem is to assess with confidence what is inconsistent. Human imagination seems to be the test for existence. But what else can we do? |
| 3959 | There is no other substance, in a strict sense, than spirit [Berkeley] |
| Full Idea: There is no other substance, in a strict sense, than spirit. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.257) | |
| A reaction: A nice clear statement of idealism. Why is he so confident of making this assertion. Note the addition, though, of 'in a strict' sense. He is presenting an epistemological claim as if it was an ontological one. |
| 18839 | An object that is not clearly red or orange can still be red-or-orange, which sweeps up problem cases [Rumfitt] |
| Full Idea: A borderline red-orange object satisfies the disjunctive predicate 'red or orange', even though it satisfies neither 'red' or 'orange'. When applied to adjacent bands of colour, the disjunction 'sweeps up' objects which are reddish-orange. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 8.5) | |
| A reaction: Rumfitt offers a formal principle in support of this. There may be a problem with 'adjacent'. Different colour systems will place different colours adjacent to red. In other examples the idea of 'adjacent' may make no sense. Rumfitt knows this! |
| 18838 | The extension of a colour is decided by a concept's place in a network of contraries [Rumfitt] |
| Full Idea: On Sainsbury's picture, a colour has an extension that it has by virtue of its place in a network of contrary colour classifications. Something is determined to be 'red' by being a colour incompatible with orange, yellow, green, blue, indigo and violet. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 8.5) | |
| A reaction: Along with Idea 18839, this gives quite a nice account of vagueness, by requiring a foil to the vague predicate, and using the disjunction of the predicate and its foil to handle anything caught in between them. |
| 18816 | Metaphysical modalities respect the actual identities of things [Rumfitt] |
| Full Idea: The central characteristic mark of metaphysical necessity is that a metaphysical possibility respects the actual identities of things - in a capacious sense of 'thing'. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 3.4) | |
| A reaction: He contrast this with logical necessity, and concludes that some truths are metaphysically but not logically necessary, such as 'Hesperus is identical with Phosphorus'. Personally I like the idea of a 'necessity-maker', so that fits. |
| 18825 | S5 is the logic of logical necessity [Rumfitt] |
| Full Idea: I accept the widely held thesis that S5 is the logic of logical necessity. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 6.4 n16) | |
| A reaction: It seems plausible that S5 is also the logic of metaphysical necessity, but that does not make them the same thing. The two types of necessity have two different grounds. |
| 3946 | A thing is shown to be impossible if a contradiction is demonstrated within its definition [Berkeley] |
| Full Idea: A thing is shown to be impossible when a repugnancy is demonstrated between the ideas comprehended in its definition. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.214) | |
| A reaction: The problem is always that imagination is needed to see the 'repugnancy', and that is relative and limited. |
| 18828 | If two possibilities can't share a determiner, they are incompatible [Rumfitt] |
| Full Idea: Two possibilities are incompatible when no possibility determines both. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 7.1) | |
| A reaction: This strikes me as just the right sort of language for building up a decent metaphysical picture of the world, which needs to incorporate possibilities as well as actualities. |
| 18824 | Since possibilities are properties of the world, calling 'red' the determination of a determinable seems right [Rumfitt] |
| Full Idea: Some philosophers describe the colour scarlet as a determination of the determinable red; since the ways the world might be are naturally taken to be properties of the world, it helps to bear this analogy in mind. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 6.4) | |
| A reaction: This fits nicely with the disposition accounts of modality which I favour. Hence being 'coloured' is a real property of objects, even in the absence of the name of its specific colour. |
| 18821 | Possibilities are like possible worlds, but not fully determinate or complete [Rumfitt] |
| Full Idea: Possibilities are things of the same general character as possible worlds, on one popular conception of the latter. They differ from worlds, though, in that they are not required to be fully determinate or complete. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 6) | |
| A reaction: A rather promising approach to such things, even though a possibility is fairly determinate at its core, but very vague at the edges. It is possible that the UK parliament might be located in Birmingham, for example. Is this world 'complete'? |
| 18831 | Medieval logicians said understanding A also involved understanding not-A [Rumfitt] |
| Full Idea: Mediaeval logicians had a principle, 'Eadem est scientia oppositorum': in order to attain a clear conception of what it is for A to be the case, one needs to attain a conception of what it is for A not to be the case. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 7.2) | |
| A reaction: Presumably 'understanding' has to be a fairly comprehensive grasp of the matter, so understanding the negation sounds like a reasonable requirement for the real thing. |
| 3958 | Since our ideas vary when the real things are said to be unchanged, they cannot be true copies [Berkeley] |
| Full Idea: As our ideas are perpetually varied, without any change in the supposed real things, it necessarily follows that they cannot all be true copies of them. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.239) | |
| A reaction: This seems a good objection to any direct or naïve realist view. Colours get darker as the sun goes down, and objects become blurred as they recede into the distance. |
| 3943 | If existence is perceived directly, by which sense; if indirectly, how is it inferred from direct perception? [Berkeley] |
| Full Idea: Either you perceive the being of matter immediately, or mediately; if immediately, pray inform me by which of the senses you perceive it; if mediately, let me know by what reasonings it is inferred from those things which you perceive immediately. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.208) | |
| A reaction: A problem for strong empiricists, and he is right that existence can't be directly perceived, but it seems a good explanation (for which some reason can be shown), and supports a more rationalist view. |
| 3931 | Sensible objects are just sets of sensible qualities [Berkeley] |
| Full Idea: Sensible things are nothing else but so many sensible qualities. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.154) | |
| A reaction: As it stands this is phenomenalism, but Berkeley eventually votes for idealism. He should acknowledge possible sensations which aren't actually experienced. |
| 5192 | Berkeley did not deny material things; he merely said they must be defined through sensations [Berkeley, by Ayer] |
| Full Idea: Berkeley did not (as we are commonly told) deny the reality of material things. ..What Berkeley discovered was that material things must be defined in terms of sense-contents. | |
| From: report of George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by A.J. Ayer - Language,Truth and Logic Ch.2 | |
| A reaction: This seems to be a rather debatable attempt to claim that Berkeley was a phenomenalist (like Ayer), rather than an idealist. Try ideas 3942, 3944, 3945, 3957, 3959 in this database. |
| 5174 | Berkeley needed a phenomenalist account of the self, as well as of material things [Ayer on Berkeley] |
| Full Idea: The considerations which make it necessary, as Berkeley saw, to give a phenomenalist account of material things, make it necessary also, as Berkeley did not see, to give a phenomenalist account of the self. | |
| From: comment on George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by A.J. Ayer - Language,Truth and Logic Ch.7 | |
| A reaction: Phenomenalism involves 'possible' experiences as well as actual ones. That could add up to quite a rich and stable account of the self, as opposed to Hume's notorious introspection, which only saw an actual shifting 'bundle' of experience. |
| 1103 | 'To be is to be perceived' is a simple confusion of experience with its objects [Russell on Berkeley] |
| Full Idea: Berkeley thinks 'to be is to be perceived', and only God provides continuity. He has simply confused the experience of perception with the thing being perceived. Ideas have content. | |
| From: comment on George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by Bertrand Russell - Problems of Philosophy |
| 6403 | For Berkelely, reality is ideas and a community of minds, including God's [Berkeley, by Grayling] |
| Full Idea: Berkeley's thesis is that reality ultimately consists of a community of minds and their ideas; one of the minds (God) is infinite, and causes most of the ideas. | |
| From: report of George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by A.C. Grayling - Russell Ch.2 | |
| A reaction: I think Russell nicely pinpoints what is wrong with Berekely, which is that he confuses ideas with their contents. If I think about my garden, the garden is real (probably), which is the content, and they idea is just a way of thinking. |
| 3936 | Time is measured by the succession of ideas in our minds [Berkeley] |
| Full Idea: Time is measured by the succession of ideas in our minds. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.172) | |
| A reaction: But we distinguish between subjective time (which flies when you are having fun), and objective time, judged from observation of clocks and nature. |
| 3930 | There is no such thing as 'material substance' [Berkeley] |
| Full Idea: That there is no such thing as what philosophers call 'material substance', I am seriously persuaded. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.150) | |
| A reaction: I'm sorry, but I can't do with this. It confuses epistemology with ontology. Ontology is a matter of judgement; epistemology is the evidence on which we base it. We know sensations; personally I judge that there are material substances. What about you? |
| 3939 | I conceive a tree in my mind, but I cannot prove that its existence can be conceived outside a mind [Berkeley] |
| Full Idea: I may conceive in my own thoughts the idea of a tree, but that is all. And this is far from proving that I can conceive it existing out of the minds of all spirits. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.184) | |
| A reaction: If Berkeley has based a world view on this point, then his mistake is to require a 'proof'. Aristotle explained why you can't prove everything (not to mention Gödel). |
| 3945 | There is nothing in nature which needs the concept of matter to explain it [Berkeley] |
| Full Idea: I challenge you to show me that thing in nature which needs matter to explain or account for it. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.212) | |
| A reaction: I disagree. Physics is a good theory for explaining why we have perceptions. Failing that there is not even a glimmer of an explanation of our experiences. |
| 3947 | Perceptions are ideas, and ideas exist in the mind, so objects only exist in the mind [Berkeley] |
| Full Idea: Wood, fire, water, flesh, iron, are things that I know, and only known because I perceive them by my senses; these are immediately perceived, and so are ideas; ideas cannot exist without the mind; their existence consists therefore in being perceived. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.220) | |
| A reaction: This makes no distinction between an idea and its content. Berkeley fails to grasp the weird concept of intentionality. Trees aren't in my head, just because I think about them! |
| 3933 | Primary qualities (such as shape, solidity, mass) are held to really exist, unlike secondary qualities [Berkeley] |
| Full Idea: Sensible qualities are by philosophers divided into primary and secondary; the former are extension, figure, solidity, gravity, motion and rest, which exist really in bodies. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.169) | |
| A reaction: A crucial distinction, which anti-realists such as Berkeley end up denying. I think it is a good distinction, and philosophers should fight to preserve it. |
| 3934 | A mite would see its own foot as large, though we would see it as tiny [Berkeley] |
| Full Idea: A mite must be supposed to see his own foot as a body of some considerable dimension, though they appear to you scarcely discernible. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.170) | |
| A reaction: Berkeley is confused. Hot is secondary, but temperature is primary. Bigness is secondary, size primay. Midgets and tall people don't disagree over the size of a table. |
| 3935 | The apparent size of an object varies with its distance away, so that can't be a property of the object [Berkeley] |
| Full Idea: As we approach to or recede from an object, the visible extension varies, being at one distance ten or a hundred times greater than at another; doth it not follow that it is not really inherent in the object? | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.171) | |
| A reaction: Berkeley is confused, because he is too literally empirical. Qualities are not self-evidently primary or secondary, but are judged so after comparisons (e.g. with testimony, or with the other senses). |
| 3937 | 'Solidity' is either not a sensible quality at all, or it is clearly relative to our senses [Berkeley] |
| Full Idea: By 'solidity' either you do not mean any sensible quality, and so it is beside our enquiry; or if you do, it must be hardness or resistance, which are plainly relative to our senses. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.173) | |
| A reaction: Berkeley fails to recognise that a quality can have primary and secondary aspects (hot/high temperature). He is right that primary qualities are not directly perceived. They are judgements. |
| 3940 | Distance is not directly perceived by sight [Berkeley] |
| Full Idea: Distance is not properly and immediately perceived by sight. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.186) | |
| A reaction: Interestingly, if secondary qualities are not strictly perceptions of the object, and primary qualities are not directly perceived, then we don't seem to perceive anything at all. Perhaps we should drop the concept of 'perception'? |
| 3957 | Immediate objects of perception, which some treat as appearances, I treat as the real things themselves [Berkeley] |
| Full Idea: Those immediate objects of perception, which, according to you, are only appearances of things, I take to be the real things themselves. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.237) | |
| A reaction: If that is a judgement, which it seems to be, it is a strange one. Realists offer a much better explanation of perceptions. |
| 3953 | Real things and imaginary or dreamed things differ because the latter are much fainter [Berkeley] |
| Full Idea: The difference between real things, and chimeras formed by the imagination, or the visions of a dream, is that the latter are faint and indistinct. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.225) | |
| A reaction: In Hume this becomes 'impressions' and 'ideas'. It does raise the question of WHY some ideas are not as faint as others. |
| 3938 | Geometry is originally perceived by senses, and so is not purely intellectual [Berkeley] |
| Full Idea: Figures and extension, being originally perceived by sense, do not belong to pure intellect. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.176) | |
| A reaction: Is the square root of 169 less 'pure' in my mind if I learn it from laying out bricks instead of by thinking about numbers? Confusion of how you learn with what you learn? |
| 18820 | In English 'evidence' is a mass term, qualified by 'little' and 'more' [Rumfitt] |
| Full Idea: In English, the word 'evidence' behaves as a mass term: we speak of someone's having little evidence for an assertion, and of one thinker's having more evidence than another for a claim. One the other hand, we also speak of 'pieces' of evidence. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 5.2) | |
| A reaction: And having 'more' evidence does not mean having a larger number of pieces of evidence, so it really is like an accumulated mass. |
| 3944 | It is possible that we could perceive everything as we do now, but nothing actually existed. [Berkeley] |
| Full Idea: We might perceive all things just as we do now, though there was no matter in the world. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.209) | |
| A reaction: An old Greek argument. Now we have an explanation of experience, but we wouldn't if nothing existed. Which doesn't prove that anything exists. Is some explanation always preferable to none? Cf. religion. |
| 3932 | A hot hand and a cold hand will have different experiences in the same tepid water [Berkeley] |
| Full Idea: Suppose now one of your hands hot, and the other cold, and that they are both at once put into the same vessel of water, in an intermediate state; will not the water seem cold to one hand, and warm to the other? | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.158) | |
| A reaction: A nice clear example of how some relativism must be acknowledged. It feels hot, but what is its temperature in degrees C? |
| 3948 | Experience tells me that other minds exist independently from my own [Berkeley] |
| Full Idea: It is plain that other minds have an existence exterior to my mind, since I find them by experience to be independent of it. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.220) | |
| A reaction: This is a surprising claim from Berkeley. If trees only exist through their experience in my mind, why don't other minds exist in the same way? |
| 3941 | How can that which is unthinking be a cause of thought? [Berkeley] |
| Full Idea: How can that which is unthinking be a cause of thought? | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.203) | |
| A reaction: Presumably, though, he thinks that thought can cause 'that which is unthinking' to move'. He likes one half of the interaction problem (which supports dualism), but avoids the other half. |
| 5374 | Berkeley probably used 'idea' to mean both the act of apprehension and the thing apprehended [Russell on Berkeley] |
| Full Idea: Berkeley seems to have confused the colour of the thing apprehended with the act of apprehension; probably either of these would have been called an 'idea' be Berkeley. | |
| From: comment on George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by Bertrand Russell - Problems of Philosophy | |
| A reaction: If we are saying that Berkeley's error was entirely verbal, there is a chicken-and-egg problem. He was an idealist, so he wouldn't have thought that there were two separate concepts behind the word 'idea'. Russell merely asserts that there are. |
| 18817 | We understand conditionals, but disagree over their truth-conditions [Rumfitt] |
| Full Idea: It is striking that our understanding of conditionals is not greatly impeded by widespread disagreement about their truth-conditions. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 4.2) | |
| A reaction: Compare 'if you dig there you might find gold' with 'if you dig there you will definitely find gold'. The second but not the first invites 'how do you know that?', implying truth. Two different ifs. |
| 18829 | The truth grounds for 'not A' are the possibilities incompatible with truth grounds for A [Rumfitt] |
| Full Idea: The truth-grounds of '¬A' are precisely those possibilities that are incompatible with any truth-ground of A. | |
| From: Ian Rumfitt (The Boundary Stones of Thought [2015], 7.1) | |
| A reaction: This is Rumfitt's proposal for the semantics of 'not', based on the central idea of a possibility, rather than a possible world. The incompatibility tracks back to an absence of shared grounding. |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| Full Idea: In singing and playing the lyre, a boy will be likely to reveal not only courage and moderation, but also justice. | |
| From: Damon (fragments/reports [c.460 BCE], B4), quoted by (who?) - where? |
| 3954 | Immorality is not in the action, but in the deviation of the will from moral law [Berkeley] |
| Full Idea: Sin or moral turpitude doth not consist in the outward physical action or motion, but in the internal deviation of the will from the laws of reason and religion. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.227) | |
| A reaction: A Kantian view (that the only good thing is a good will). It is a very empiricist (and anti-Greek) view to deny that actions have any intrinsic value. |
| 3950 | There must be a God, because all sensible things must be perceived by him [Berkeley] |
| Full Idea: I immediately and necessarily conclude the being of a God, because all sensible things must be perceived by him. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.198) | |
| A reaction: Daft. This contradicts Berkeley's whole empiricist position, that existence depends on known experience. Who knows whether God is thinking about trees? |
| 3951 | There must be a God, because I and my ideas are not independent [Berkeley] |
| Full Idea: From the dependency I find in myself and my ideas, I do by an act of reason necessarily infer the existence of a God. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.222) | |
| A reaction: No. Hume answered this, by showing how big abstract ideas are built up from experience. This is a future bishop's wish-fulfilment. |
| 3949 | It has been proved that creation is the workmanship of God, from its beauty and usefulness [Berkeley] |
| Full Idea: Divines and philosophers have proved beyond all controversy, from the beauty and usefulness of the several parts of creation, that it was the workmanship of God. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.198) | |
| A reaction: Not convincing. Beauty is probably a sublimation of sexual desire (or an echo of the human mind in the external world, in music), and utility is relative to homo sapiens, I presume. |
| 3956 | People are responsible because they have limited power, though this ultimately derives from God [Berkeley] |
| Full Idea: Thinking rational beings, in the production of motions, have the use of limited powers, ultimately derived from God, but immediately under the direction of their own wills, which is sufficient to entitle them to all the guilt of their own actions. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.228) | |
| A reaction: An episcopal evasion. A classic attempt to have cake and eat it. Either God is in charge or he isn't. |
| 3955 | If sin is not just physical, we don't consider God the origin of sin because he causes physical events [Berkeley] |
| Full Idea: If sin doth not consist of purely physical actions, the making God a cause of all such actions, is not making him the author of sin. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.227) | |
| A reaction: An equivocation. If responsibility resides in consciousness, God is presumably conscious, and we can judge the events he causes. |