103 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. |
| 224 | When questions are doubtful we should concentrate not on objects but on ideas of the intellect [Plato] |
| Full Idea: Doubtful questions should not be discussed in terms of visible objects or in relation to them, but only with reference to ideas conceived by the intellect. | |
| From: Plato (Parmenides [c.364 BCE], 135e) |
| 232 | Opposites are as unlike as possible [Plato] |
| Full Idea: Opposites are as unlike as possible. | |
| From: Plato (Parmenides [c.364 BCE], 159a) |
| 8937 | Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic [Hegel on Plato] |
| Full Idea: Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic. | |
| From: comment on Plato (Parmenides [c.364 BCE]) by Georg W.F.Hegel - Phenomenology of Spirit Pref 71 | |
| A reaction: It is a long way from the analytic tradition of philosophy to be singling out a classic text for its 'artistic' achievement. Eventually we may even look back on, say, Kripke's 'Naming and Necessity' and see it in that light. |
| 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. |
| 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. |
| 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. |
| 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. |
| 13986 | Plato found antinomies in ideas, Kant in space and time, and Bradley in relations [Plato, by Ryle] |
| Full Idea: Plato (in 'Parmenides') shows that the theory that 'Eide' are substances, and Kant that space and time are substances, and Bradley that relations are substances, all lead to aninomies. | |
| From: report of Plato (Parmenides [c.364 BCE]) by Gilbert Ryle - Are there propositions? 'Objections' |
| 14150 | Plato's 'Parmenides' is perhaps the best collection of antinomies ever made [Russell on Plato] |
| Full Idea: Plato's 'Parmenides' is perhaps the best collection of antinomies ever made. | |
| From: comment on Plato (Parmenides [c.364 BCE]) by Bertrand Russell - The Principles of Mathematics §337 |
| 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). |
| 16150 | One is, so numbers exist, so endless numbers exist, and each one must partake of being [Plato] |
| Full Idea: If one is, there must also necessarily be number - Necessarily - But if there is number, there would be many, and an unlimited multitude of beings. ..So if all partakes of being, each part of number would also partake of it. | |
| From: Plato (Parmenides [c.364 BCE], 144a) | |
| A reaction: This seems to commit to numbers having being, then to too many numbers, and hence to too much being - but without backing down and wondering whether numbers had being after all. Aristotle disagreed. |
| 229 | The one was and is and will be and was becoming and is becoming and will become [Plato] |
| Full Idea: The one was and is and will be and was becoming and is becoming and will become. | |
| From: Plato (Parmenides [c.364 BCE], 155d) |
| 21821 | Plato's Parmenides has a three-part theory, of Primal One, a One-Many, and a One-and-Many [Plato, by Plotinus] |
| Full Idea: The Platonic Parmenides is more exact [than Parmenides himself]; the distinction is made between the Primal One, a strictly pure Unity, and a secondary One which is a One-Many, and a third which is a One-and-Many. | |
| From: report of Plato (Parmenides [c.364 BCE]) by Plotinus - The Enneads 5.1.08 | |
| A reaction: Plotinus approves of this three-part theory. Parmenides has the problem that the highest Being contains no movement. By placing the One outside Being you can give it powers which an existent thing cannot have. Cf the concept of God. |
| 221 | Absolute ideas, such as the Good and the Beautiful, cannot be known by us [Plato] |
| Full Idea: The absolute good and the beautiful and all which we conceive to be absolute ideas are unknown to us. | |
| From: Plato (Parmenides [c.364 BCE], 134c) |
| 223 | If you deny that each thing always stays the same, you destroy the possibility of discussion [Plato] |
| Full Idea: If a person denies that the idea of each thing is always the same, he will utterly destroy the power of carrying on discussion. | |
| From: Plato (Parmenides [c.364 BCE], 135c) |
| 227 | You must always mean the same thing when you utter the same name [Plato] |
| Full Idea: You must always mean the same thing when you utter the same name. | |
| From: Plato (Parmenides [c.364 BCE], 147d) |
| 210 | It would be absurd to think there were abstract Forms for vile things like hair, mud and dirt [Plato] |
| Full Idea: Are there abstract ideas for such things as hair, mud and dirt, which are particularly vile and worthless? That would be quite absurd. | |
| From: Plato (Parmenides [c.364 BCE], 130d) |
| 220 | The concept of a master includes the concept of a slave [Plato] |
| Full Idea: Mastership in the abstract is mastership of slavery in the abstract. | |
| From: Plato (Parmenides [c.364 BCE], 133e) |
| 211 | If admirable things have Forms, maybe everything else does as well [Plato] |
| Full Idea: It is troubling that if admirable things have abstract ideas, then perhaps everything else must have ideas as well. | |
| From: Plato (Parmenides [c.364 BCE], 130d) |
| 219 | If absolute ideas existed in us, they would cease to be absolute [Plato] |
| Full Idea: None of the absolute ideas exists in us, because then it would no longer be absolute. | |
| From: Plato (Parmenides [c.364 BCE], 133c) |
| 228 | Greatness and smallness must exist, to be opposed to one another, and come into being in things [Plato] |
| Full Idea: These two ideas, greatness and smallness, exist, do they not? For if they did not exist, they could not be opposites of one another, and could not come into being in things. | |
| From: Plato (Parmenides [c.364 BCE], 149e) |
| 16151 | Plato moves from Forms to a theory of genera and principles in his later work [Plato, by Frede,M] |
| Full Idea: It seems to me that Plato in the later dialogues, beginning with the second half of 'Parmenides', wants to substitute a theory of genera and theory of principles that constitute these genera for the earlier theory of forms. | |
| From: report of Plato (Parmenides [c.364 BCE]) by Michael Frede - Title, Unity, Authenticity of the 'Categories' V | |
| A reaction: My theory is that the later Plato came under the influence of the brilliant young Aristotle, and this idea is a symptom of it. The theory of 'principles' sounds like hylomorphism to me. |
| 218 | Participation is not by means of similarity, so we are looking for some other method of participation [Plato] |
| Full Idea: Participation is not by means of likeness, so we must seek some other method of participation. | |
| From: Plato (Parmenides [c.364 BCE], 133a) |
| 215 | If things partake of ideas, this implies either that everything thinks, or that everything actually is thought [Plato] |
| Full Idea: If all things partake of ideas, must either everything be made of thoughts and everything thinks, or everything is thought, and so can't think? | |
| From: Plato (Parmenides [c.364 BCE], 132c) |
| 212 | The whole idea of each Form must be found in each thing which participates in it [Plato] |
| Full Idea: The whole idea of each form (of beauty, justice etc) must be found in each thing which participates in it. | |
| From: Plato (Parmenides [c.364 BCE], 131a) |
| 213 | Each idea is in all its participants at once, just as daytime is a unity but in many separate places at once [Plato] |
| Full Idea: Just as day is in many places at once, but not separated from itself, so each idea might be in all its participants at once. | |
| From: Plato (Parmenides [c.364 BCE], 131b) |
| 216 | If things are made alike by participating in something, that thing will be the absolute idea [Plato] |
| Full Idea: That by participation in which like things are made like, will be the absolute idea, will it not? | |
| From: Plato (Parmenides [c.364 BCE], 132e) |
| 217 | Nothing can be like an absolute idea, because a third idea intervenes to make them alike (leading to a regress) [Plato] |
| Full Idea: It is impossible for anything to be like an absolute idea, because a third idea will appear to make them alike, and if that is like anything, it will lead to another idea, and so on. | |
| From: Plato (Parmenides [c.364 BCE], 133a) |
| 214 | If absolute greatness and great things are seen as the same, another thing appears which makes them seem great [Plato] |
| Full Idea: If you regard the absolute great and the many great things in the same way, will not another appear beyond, by which all these must appear to be great? | |
| From: Plato (Parmenides [c.364 BCE], 132a) |
| 15851 | Parts must belong to a created thing with a distinct form [Plato] |
| Full Idea: The part would not be the part of many things or all, but of some one character ['ideas'] and of some one thing, which we call a 'whole', since it has come to be one complete [perfected] thing composed [created] of all. | |
| From: Plato (Parmenides [c.364 BCE], 157d) | |
| A reaction: A serious shot by Plato at what identity is. Harte quotes it (125) and shows that 'character' is Gk 'idea', and 'composed' will translate as 'created'. 'Form' links this Platonic passage to Aristotle's hylomorphism. |
| 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. |
| 15846 | In Parmenides, if composition is identity, a whole is nothing more than its parts [Plato, by Harte,V] |
| Full Idea: At the heart of the 'Parmenides' puzzles about composition is the thesis that composition is identity. Considered thus, a whole adds nothing to an ontology that already includes its parts | |
| From: report of Plato (Parmenides [c.364 BCE]) by Verity Harte - Plato on Parts and Wholes 2.5 | |
| A reaction: There has to be more to a unified identity that mere proximity of the parts. When do parts come together, and when do they actually 'compose' something? |
| 15849 | Plato says only a one has parts, and a many does not [Plato, by Harte,V] |
| Full Idea: In 'Parmenides' it is argued that a part cannot be part of a many, but must be part of something one. | |
| From: report of Plato (Parmenides [c.364 BCE], 157c) by Verity Harte - Plato on Parts and Wholes 3.2 | |
| A reaction: This looks like the right way to go with the term 'part'. We presuppose a unity before we even talk of its parts, so we can't get into contradictions and paradoxes about their relationships. |
| 15850 | Anything which has parts must be one thing, and parts are of a one, not of a many [Plato] |
| Full Idea: The whole of which the parts are parts must be one thing composed of many; for each of the parts must be part, not of a many, but of a whole. | |
| From: Plato (Parmenides [c.364 BCE], 157c) | |
| A reaction: This is a key move of metaphysics, and we should hang on to it. The other way madness lies. |
| 13259 | It seems that the One must be composed of parts, which contradicts its being one [Plato] |
| Full Idea: The One must be composed of parts, both being a whole and having parts. So on both grounds the One would thus be many and not one. But it must be not many, but one. So if the One will be one, it will neither be a whole, nor have parts. | |
| From: Plato (Parmenides [c.364 BCE], 137c09), quoted by Kathrin Koslicki - The Structure of Objects 5.2 | |
| A reaction: This is the starting point for Plato's metaphysical discussion of objects. It seems to begin a line of thought which is completed by Aristotle, surmising that only an essential structure can bestow identity on a bunch of parts. |
| 15847 | Two things relate either as same or different, or part of a whole, or the whole of the part [Plato] |
| Full Idea: Everything is surely related to everything as follows: either it is the same or different; or, if it is not the same or different, it would be related as part to whole or as whole to part. | |
| From: Plato (Parmenides [c.364 BCE], 146b) | |
| A reaction: This strikes me as a really helpful first step in trying to analyse the nature of identity. Two things are either two or (actually) one, or related mereologically. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 4363 | The word 'person' is useless in ethics, because what counts as a good or bad self-conscious being? [Hursthouse] |
| Full Idea: An excellent reason for keeping the word 'person' out of ethics is that it is usually so thinly defined that it cannot generate any sense of 'good person'. If a person is just a self-conscious being, what would count as a good or bad one? | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.9 n20) | |
| A reaction: A nice point. Locke's concept of a person (rational self-conscious being) lacks depth and individuality, and Hitler fulfils the criteria as well as any saint. But if Hitler wasn't a 'bad person', what was he bad at being? |
| 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. |
| 4355 | There may be inverse akrasia, where the agent's action is better than their judgement recommends [Hursthouse] |
| Full Idea: There seem to be cases of 'inverse akrasia', in which the course of action actually followed is superior to the course of action recommended by the agent's best judgement. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.7) | |
| A reaction: This must occur, as when an assassin lets his victim off, and then regrets the deed. It strengthens the case against Socrates, and in favour of their being two parts of the soul which compete to motivate our actions. |
| 4325 | Must all actions be caused in part by a desire, or can a belief on its own be sufficient? [Hursthouse] |
| Full Idea: In contemporary philosophy of action, there is a fervid debate about whether any intentional action must be prompted in part by desire, or whether it is possible to be moved to action by a belief alone. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Intro) | |
| A reaction: I want a cool belief to be sufficient to produce an action, because it will permit at least a Kantian dimension to ethics, and make judgement central, and marginalise emotivism, which is the spawn of Satan. |
| 4351 | It is a fantasy that only through the study of philosophy can one become virtuous [Hursthouse] |
| Full Idea: It is a fantasy that only through the study of philosophy can one become virtuous. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.6) | |
| A reaction: I personally believe that philosophy is the best route yet devised to the achievement of virtue, but it is clearly not essential. All the philosophers I meet are remarkably virtuous, but that may be a chicken/egg thing. |
| 4340 | You are not a dishonest person if a tragic dilemma forces you to do something dishonest [Hursthouse] |
| Full Idea: Doing what is, say, dishonest solely in the context of a tragic dilemma does not entail being dishonest, possessing that vice. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.3 n8) | |
| A reaction: This seems right, although it mustn't be thought that the dishonesty is thereby excused. Virtuous people find being dishonest very painful. |
| 4329 | After a moral dilemma is resolved there is still a 'remainder', requiring (say) regret [Hursthouse] |
| Full Idea: When one moral requirement has overriden another in a dilemma, there is still a 'remainder', so that regret, or the recognition of some new requirement, are still appropriate. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.2) | |
| A reaction: This is a powerful point on behalf of virtue ethics. There is a correct way to feel about the application of rules and calculations. Judges sleep well at night, but virtuous people may not. |
| 4330 | Deontologists resolve moral dilemmas by saying the rule conflict is merely apparent [Hursthouse] |
| Full Idea: With respect to resolvable dilemmas, the deontologist's strategy is to argue that the 'conflict' between the two rules which has generated the dilemma is merely apparent. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.2) | |
| A reaction: This assumes that the rules can't conflict (because they come for God, or pure reason), but we might say that there are correct rules which do conflict. Morality isn't physics, or tennis. |
| 4341 | Involuntary actions performed in tragic dilemmas are bad because they mar a good life [Hursthouse] |
| Full Idea: The actions a virtuous agent is forced to in tragic dilemmas fail to be good actions because the doing of them, no matter how unwillingly or involuntarily, mars or ruins a good life. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.3) | |
| A reaction: Of course, only virtuous people have their lives ruined by such things. For the cold or the wicked it is just water off a duck's back. |
| 4358 | Virtue may be neither sufficient nor necessary for eudaimonia [Hursthouse] |
| Full Idea: Some critics say virtue is not necessary for eudaimonia (since the wicked sometimes flourish), and others say it is not sufficient (because virtuous behaviour sometimes ruins a life). | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.8) | |
| A reaction: Both criticisms seem wrong (the wicked don't 'flourish', and complete virtue never ruins lives, except in tragic dilemmas). But it is hard to prove them wrong. |
| 4337 | Teenagers are often quite wise about ideals, but rather stupid about consequences [Hursthouse] |
| Full Idea: Adolescents tend to be much more gormless about consequences than they are about ideals. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.2 n12) | |
| A reaction: Very accurate, I'm afraid. But this cuts both ways. They seem to need education not in virtue, but simply in consequences. |
| 4324 | Animals and plants can 'flourish', but only rational beings can have eudaimonia [Hursthouse] |
| Full Idea: The trouble with 'flourishing' as a translation of 'eudaimonia' is that animals and even plants can flourish, but eudaimonia is possible only for rational beings. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Intro) | |
| A reaction: 'Flourishing' still seems better than 'happy', which is centrally used now to refer to a state of mind, not a situation. 'Well being' seems good, and plants are usually permitted that. |
| 4359 | When it comes to bringing up children, most of us think that the virtues are the best bet [Hursthouse] |
| Full Idea: If you think about bringing up children to prepare them for life, rather than converting the wicked or convincing the moral sceptic, isn't virtue the most reliable bet? | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.8) | |
| A reaction: A very convincing idea. They haven't the imagination to grasp consequences properly, or sufficient abstract thought to grasp principles, or the political cunning to negotiate contracts, but they can grasp ideals of what a good person is like. |
| 4336 | Any strict ranking of virtues or rules gets abandoned when faced with particular cases [Hursthouse] |
| Full Idea: Any codification ranking the virtues, like any codification ranking the rules, is bound to come up against cases where we will want to change the rankings. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.2) | |
| A reaction: This seems right, and yet it feels like a slippery slope. Am I supposed to be virtuous and wise, but have no principles? Infinite flexibility can lead straight to wickedness. Even the wise need something to hang on to. |
| 4334 | Virtue ethics is open to the objection that it fails to show priority among the virtues [Hursthouse] |
| Full Idea: One criticism of virtue ethics is that it lamentably fails to come up with a priority ranking of the virtues. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.2) | |
| A reaction: However, one might refer to man's essential function, or characteristic function, and one might derive the virtues of a good citizen from the nature of a good society. |
| 4361 | Good animals can survive, breed, feel characteristic pleasure and pain, and contribute to the group [Hursthouse] |
| Full Idea: A good social animal is well fitted for 1) individual survival, 2) continuance of its species, 3) characteristic freedom from pain and enjoyment, and 4) good characteristic functioning of its social group. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.9) | |
| A reaction: This feels right, but brings out the characteristic conservativism of virtue theory. A squirrel which can recite Shakespeare turns out to be immoral. |
| 4349 | Virtuous people may not be fully clear about their reasons for action [Hursthouse] |
| Full Idea: Virtue must surely be compatible with a fair amount of inarticulacy about one's reasons for action. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.6) | |
| A reaction: Virtuous people may be unclear, but we are entitled to hope for clarification from moral philosophers. The least we can hope for is some distinction between virtue and vice. |
| 4352 | Performing an act simply because it is virtuous is sufficient to be 'morally motivated' or 'dutiful' [Hursthouse] |
| Full Idea: Acting virtuously, in the way the virtuous agent acts, namely from virtue, is sufficient for being 'morally motivated' or acting 'from a sense of duty'. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.7) | |
| A reaction: Fine, but it invites the question of WHY virtue is motivating, just as one can ask this of maximum happiness, or duty, or even satisfaction of selfish desires. |
| 4353 | If moral motivation is an all-or-nothing sense of duty, how can children act morally? [Hursthouse] |
| Full Idea: If you are inclined to think that 'moral motivation', acting because you think it is right, must be an all-or-nothing matter, its presence determined by the agent's mind at the moment of acting, do, please, remember children. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.7) | |
| A reaction: I agree about the vital importance of remembering children when discussing morality. However, Kantians might legitimately claim that when a child is simply trained to behave well, it has not yet reached the age of true morality. |
| 4346 | The emotions of sympathy, compassion and love are no guarantee of right action or acting well [Hursthouse] |
| Full Idea: The emotions of sympathy, compassion and love are no guarantee of right action or acting well. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.4) | |
| A reaction: This is a critique of Hume, and of utlitarianism. It pushes us either to the concept of duty, or the concept of virtue (independent of right feeling). |
| 4339 | According to virtue ethics, two agents may respond differently, and yet both be right [Hursthouse] |
| Full Idea: According to virtue ethics, in a given situation two different agents may do what is right, what gets a tick of approval, despite the fact that each fails to do what the other did. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.3) | |
| A reaction: You could certainly have great respect for two entirely different decisions about a medical dilemma, if they both showed integrity and good will, even if one had worse consequences than the other. |
| 4354 | Maybe in a deeply poisoned character none of their milder character traits could ever be a virtue [Hursthouse] |
| Full Idea: I am prepare to stick my neck out and say that extreme Nazis or racists (say) have poisoned characters to such an extent that none of their character traits could ever count as a virtue. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.7) | |
| A reaction: Hard to justify, but it is hard to respect a mass murderer because they seem to love their dog or the beauty of music or flowers. They can't possibly appreciate the Platonic Form of love or beauty? |
| 4364 | Being unusually virtuous in some areas may entail being less virtuous in others [Hursthouse] |
| Full Idea: It may well be that being particularly well endowed with respect to some virtues inevitably involves being not very well endowed in others. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.9) | |
| A reaction: Maybe, but this sound a bit like an excuse. Newton wasn't very nice, but Einstein was. I can't believe in a finite reservoir of virtue. |
| 4356 | We are puzzled by a person who can show an exceptional virtue and also behave very badly [Hursthouse] |
| Full Idea: That we have some intuitive belief in the unity of the virtues is shown by our reaction to stories of a person who has shown an exceptional virtue, but also done something morally repellent. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.7) | |
| A reaction: A nice observation, but not enough to establish the unity of virtue. People tend to love all virtue, but it is not obviously impossible to love selected virtues and despise others (e.g. love courage, and despise charity). |
| 4327 | Deontologists do consider consequences, because they reveal when a rule might apply [Hursthouse] |
| Full Idea: Though it is sometimes said that deontologists 'take no account of consequences', this is manifestly false, for many actions we deliberate about only fall under rules or principles when we bring in their predicted consequences. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.1) | |
| A reaction: An important defence of deontology, which otherwise is vulnerable to the 'well-meaning fool' problem. It is no good having a good will, but refusing to think about consequences. |
| 4335 | 'Codifiable' morality give rules for decisions which don't require wisdom [Hursthouse] |
| Full Idea: If morality is strongly 'codifiable', it should consist of rules which provide a decision procedure, and it should be equally applicable by the virtuous and the non-virtuous, without recourse to wisdom. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.2) | |
| A reaction: A key idea. Religions want obedience, and Kant wants morality to be impersonal, and most people want morality which simple uneducated people can follow. And yet how can wisdom ever be irrelevant? |
| 4328 | Preference utilitarianism aims to be completely value-free, or empirical [Hursthouse] |
| Full Idea: There are some forms of utilitarianism which aim to be entirely 'value-free' or empirical, such as those which define happiness in terms of the satisfaction of actual desires or preferences, regardless of their content. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.1) | |
| A reaction: This point makes it clear that preference utilitarianism is a doomed enterprise. For a start I can prefer not to be a utilitarian. You can only maximise something if you value if. Are preferences valuable? |
| 4343 | We are torn between utilitarian and deontological views of lying, depending on the examples [Hursthouse] |
| Full Idea: Utilitarianism says there is nothing intrinsically wrong with lying, but examples of bare-faced lying to increase happiness drive us to deontology; but then examples where telling the truth has appalling consequences drive us back to utilitarianism again. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.3) | |
| A reaction: A nice illustration of why virtue theory suddenly seemed appealing. Deontology can cope, though, by seeing other duties when the consequences are dreadful. |
| 4338 | Deontologists usually accuse utilitarians of oversimplifying hard cases [Hursthouse] |
| Full Idea: Deontologists characteristically maintain that utilitarians have made out a particular hard case to be too simple. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.3) | |
| A reaction: Utilitarianism certainly seems to ignore the anguish of hard dilemmas, but that is supposed to be its appeal. If you think for too long, every dilemma begins to seem hopeless. |
| 4365 | We are distinct from other animals in behaving rationally - pursuing something as good, for reasons [Hursthouse] |
| Full Idea: Our characteristic way of going on, which distinguishes us from all the other species of animals, is a rational way, which is any way we can rightly see as good, as something we have reason to do. | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch10) | |
| A reaction: Some people more than others, and none of us all the time. Romantics see rationality as a restraint on the authentic emotional and animal life. 'Be a good animal'. However, I agree. |
| 222 | Only a great person can understand the essence of things, and an even greater person can teach it [Plato] |
| Full Idea: Only a man of very great natural gifts will be able to understand that everything has a class and absolute essence, and an even more wonderful man can teach this. | |
| From: Plato (Parmenides [c.364 BCE], 135a) |
| 225 | The unlimited has no shape and is endless [Plato] |
| Full Idea: The unlimited partakes neither of the round nor of the straight, because it has no ends nor edges. | |
| From: Plato (Parmenides [c.364 BCE], 137e) |
| 233 | Some things do not partake of the One [Plato] |
| Full Idea: The others cannot partake of the one in any way; they can neither partake of it nor of the whole. | |
| From: Plato (Parmenides [c.364 BCE], 159d) | |
| A reaction: Compare Idea 231 |
| 2062 | The only movement possible for the One is in space or in alteration [Plato] |
| Full Idea: If the One moves it either moves spatially or it is altered, since these are the only motions. | |
| From: Plato (Parmenides [c.364 BCE], 138b) |
| 231 | Everything partakes of the One in some way [Plato] |
| Full Idea: The others are not altogether deprived of the one, for they partake of it in some way. | |
| From: Plato (Parmenides [c.364 BCE], 157c) | |
| A reaction: Compare Idea 233. |
| 4350 | If people are virtuous in obedience to God, would they become wicked if they lost their faith? [Hursthouse] |
| Full Idea: If people perform virtuous actions simply because they are commanded by God, would they cease to perform such actions if they lost their faith in God? | |
| From: Rosalind Hursthouse (On Virtue Ethics [1999], Ch.6) | |
| A reaction: To be consistent, the answer might be 'yes', but that invites the response that only intrinsically evil people need to be Christians. The rest of us can be good without it. |
| 234 | We couldn't discuss the non-existence of the One without knowledge of it [Plato] |
| Full Idea: There must be knowledge of the one, or else not even the meaning of the words 'if the one does not exist' would be known. | |
| From: Plato (Parmenides [c.364 BCE], 160d) |