34 ideas
| 23367 | Even pointing a finger should only be done for a reason [Epictetus] |
| Full Idea: Philosophy says it is not right even to stretch out a finger without some reason. | |
| From: Epictetus (fragments/reports [c.57], 15) | |
| A reaction: The key point here is that philosophy concerns action, an idea on which Epictetus is very keen. He rather despise theory. This idea perfectly sums up the concept of the wholly rational life (which no rational person would actually want to live!). |
| 19066 | Philosophy aims to understand the world, through ordinary experience and science [Dummett] |
| Full Idea: Philosophy is an attempt to understand the world, as it is revealed to us both in our ordinary experience and by the discoveries and theories of science. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.311) | |
| A reaction: I don't see a sharp division between 'ordinary' and 'scientific'. I really like this idea, first because it makes 'understanding' central, and second because it wants both revelations. In discussing matter and time, there is too much emphasis on science. |
| 12249 | 'Animal' is a genus and 'rational' is a specific difference [Oderberg] |
| Full Idea: The standard classification holds that 'animal' is a genus and 'rational' is a specific difference. | |
| From: David S. Oderberg (Real Essentialism [2007], 3.5) | |
| A reaction: My understanding of 'difference' would take it down to the level of the individual, so the question is - which did Aristotle believe in. Not all commentators agree with Oderberg, and Wedin thinks the individual substance is paramount. |
| 12242 | Definition distinguishes one kind from another, and individuation picks out members of the kind [Oderberg] |
| Full Idea: To define something just means to set forth its limits in such a way that one can distinguish it from all other things of a different kind. To distinguish it from all other things of the same kind belongs to the theory of 'individuation'. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.4) | |
| A reaction: I take Aristotle to have included individuation as part of his understanding of definition. Are tigers a kind, or are fierce tigers a kind, and is my tiger one-of-a-kind? |
| 19067 | A successful proof requires recognition of truth at every step [Dummett] |
| Full Idea: For a demonstration to be cogent it is necessary that the passage from step to step involve a recognition of truth at each line. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.313) | |
| A reaction: Dummett cited Quine (esp. 1970) as having an almost entirely syntactic view of logic. Rumfitt points out that logic can move validly from one falsehood to another. Even a 'proof' might detour into falsehood, but it would not be a 'canonical' proof! |
| 19060 | Truth-tables are dubious in some cases, and may be a bad way to explain connective meaning [Dummett] |
| Full Idea: It is arguable whether two-valued truth tables give correct meanings for certain sentential operators, and even whether they constitute legitimate explanations of any possible sentential operators. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: See 'Many-valued logic' for examples of non-binary truth tables. Presumably logicians should aspire to make their semantics precise, as well as their syntax. |
| 11066 | Deduction is justified by the semantics of its metalanguage [Dummett, by Hanna] |
| Full Idea: For Dummett the semantics of the metalanguage is the external and objective source of the justification of deduction. | |
| From: report of Michael Dummett (The Justification of Deduction [1973]) by Robert Hanna - Rationality and Logic 3.4 | |
| A reaction: This is offered as an answer to the Lewis Carroll problem that justifying deduction seems to need deduction, thus leading to a regress. [There is a reply to Dummett by Susan Haack] |
| 19058 | Syntactic consequence is positive, for validity; semantic version is negative, with counterexamples [Dummett] |
| Full Idea: A plausible account is that the syntactic notion of consequence is for positive results, that some form of argument is valid; the semantic notion is required for negative results, that some argument is invalid, because a counterexample can be found. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.292) | |
| A reaction: This rings true for the two strategies of demonstration, the first by following the rules in steps, the second by using your imagination (or a tableau) to think up problems. |
| 19063 | Beth trees show semantics for intuitionistic logic, in terms of how truth has been established [Dummett] |
| Full Idea: Beth trees give a semantics for intuitionistic logic, by representing sentence meaning in terms of conditions under which it is recognised to have been established as true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) |
| 19059 | In standard views you could replace 'true' and 'false' with mere 0 and 1 [Dummett] |
| Full Idea: Nothing is lost, on this view, if in the standard semantic treatment of classical sentential logic, we replace the standard truth-values 'true' and 'false' by the numbers 0 and 1. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: [A long context will explain 'on this view'] He is discussing the relationship of syntactic and semantic consequence, and goes on to criticise simple binary truth-table accounts of connectives. Semantics on a computer would just be 0 and 1. |
| 19062 | Classical two-valued semantics implies that meaning is grasped through truth-conditions [Dummett] |
| Full Idea: The standard two-valued semantics for classical logic involves a conception under which to grasp the meaning of a sentence is to apprehend the conditions under which it is, or is not, true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) | |
| A reaction: The idea is that you only have to grasp the truth tables for sentential logic, and that needs nothing more than knowing whether a sentence is true or false. I'm not sure where the 'conditions' creep in, though. |
| 19065 | Soundness and completeness proofs test the theory of meaning, rather than the logic theory [Dummett] |
| Full Idea: A proof of soundess or completeness is a test, not so much of the logical theory to which it applies, but of the theory of meaning which underlies the semantics. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.310) | |
| A reaction: These two types of proof concern how the syntax and the semantics match up, so this claim sounds plausible, though I tend to think of them as more like roadworthiness tests for logic, checking how well they function. |
| 12238 | The Aristotelian view is that numbers depend on (and are abstracted from) other things [Oderberg] |
| Full Idea: The Aristotelian account of numbers is that their existence depends on the existence of things that are not numbers, ..since numbers are abstractions from the existence of things. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.2) | |
| A reaction: This is the deeply unfashionable view to which I am attached. The problem is the status of transfinite, complex etc numbers. They look like fictions to me. |
| 12254 | Being is substantial/accidental, complete/incomplete, necessary/contingent, possible, relative, intrinsic.. [Oderberg] |
| Full Idea: Being is heterogeneous: there is substantial being, accidental being, complete being, incomplete being, necessary being, contingent being, possible being, absolute being, relative being, intrinsic being, extrinsic being, and so on. | |
| From: David S. Oderberg (Real Essentialism [2007], 5.3) | |
| A reaction: Dependent being? Oderberg is giving the modern scholastic view. Personally I take 'being' to be univocal, even if it can be qualified in all sorts of ways. I don't believe we actually have any grasp at all of different ways to exist. |
| 12253 | If tropes are in space and time, in what sense are they abstract? [Oderberg] |
| Full Idea: If tropes are in space and time, in what sense are they abstract? | |
| From: David S. Oderberg (Real Essentialism [2007], 4.5) | |
| A reaction: I take this to be a conclusive objection to claims for any such thing to be abstract. See, for example, Dummett's claim that the Equator is an abstract object. |
| 12256 | We need to distinguish the essential from the non-essential powers [Oderberg] |
| Full Idea: We need a theory of essence to help us distinguish between the powers that do and do not belong to the essence of a thing. | |
| From: David S. Oderberg (Real Essentialism [2007], 6.3) | |
| A reaction: I take this to be a very good reason for searching for the essence of things, though the need to distinguish does not guarantee that there really is something to distinguish. Maybe powers just come and go. A power is essential in you but not in me? |
| 12252 | Empiricists gave up 'substance', as unknowable substratum, or reducible to a bundle [Oderberg] |
| Full Idea: The demise of 'substance' was wholly due to mistaken notions, mainly from the empiricists, by which it was conceived either as an unknowable featureless substratum, or as dispensable in favour of some or other bundle theory. | |
| From: David S. Oderberg (Real Essentialism [2007], 4.4) | |
| A reaction: There seems to be a view that the notion of substance is essential to explaining how we understand the world. I am inclined to think that if we accept the notion of essence we can totally dispense with the notion of substance. |
| 12241 | Essences are real, about being, knowable, definable and classifiable [Oderberg, by PG] |
| Full Idea: Real essences are objectively real, they concern being, they are knowable, they are definable, and they are classifiable. | |
| From: report of David S. Oderberg (Real Essentialism [2007], 1.4) by PG - Db (ideas) | |
| A reaction: This is a lovely summary (spread over two pages) of what essentialism is all about. It might be added that they are about unity and identity. The fact that they are intrinsically classifiable seems to mislead some people into a confused view. |
| 12244 | Nominalism is consistent with individual but not with universal essences [Oderberg] |
| Full Idea: Nominalism is consistent with belief in individual essences, but real essentialism postulates essences as universals (quiddities). Nominalists are nearly always empiricists, though the converse may not be the case. | |
| From: David S. Oderberg (Real Essentialism [2007], 2.1) | |
| A reaction: This is where I part company with Oderberg. I want to argue that the nominalist/individualist view is more in tune with what Aristotle believed (though he spotted a dilemma here). Only individual essences explain individual behaviour. |
| 12240 | Essentialism is the main account of the unity of objects [Oderberg] |
| Full Idea: Real essentialism, more than any other ontological theory, stresses and seeks to explain the unity of objects. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.3) | |
| A reaction: A key piece in the jigsaw I am beginning to assemble. If explanation is the aim, and essence the key to explanation, then explaining unity is the part of it that connects with other metaphysics, about identity and so on. 'Units' breed numbers. |
| 12247 | Essence is not explanatory but constitutive [Oderberg] |
| Full Idea: Essence is not reducible to explanatory relations, ...and fundamentally the role of essence is not explanatory but constitutive. | |
| From: David S. Oderberg (Real Essentialism [2007], 3.1) | |
| A reaction: Effectively, this asserts essence as part of 'pure' metaphysics, but I like impure metaphysics, as the best explanation of the things we can know. Hence we can speculate about constitution only by means of explanation. Constitution is active. |
| 12258 | Properties are not part of an essence, but they flow from it [Oderberg] |
| Full Idea: A substance is constituted by its essence, and properties are a species of accident. No property of a thing is part of a thing's essence, though properties flow from the essence. | |
| From: David S. Oderberg (Real Essentialism [2007], 7.2) | |
| A reaction: I'm not sure I understand this. How can you know of something which has no properties? I'm wondering if the whole notion of a 'property' should be eliminated from good metaphysics. |
| 12257 | Could we replace essence with collections of powers? [Oderberg] |
| Full Idea: Why not do away with talk of essences and replace it with talk of powers pure and simple, or reduce essences to collections of powers? But then what unites the powers, and could a power be lost, and is there entailment between the powers? | |
| From: David S. Oderberg (Real Essentialism [2007], 6.3) | |
| A reaction: [He cites Bennett and Hacker 2003 for this view] The point would seem to be that in addition to the powers, there are also identity and unity and kind-membership to be explained. Oderberg says the powers flow from the essence. |
| 12236 | Leibniz's Law is an essentialist truth [Oderberg] |
| Full Idea: Leibniz's Law is an essentialist truth. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: That is, if two things must have identical properties because they are the same thing, this is because those properties are essential to the thing. Otherwise two things could be the same, even though one of them lacked a non-identifying property. |
| 12250 | Bodies have act and potency, the latter explaining new kinds of existence [Oderberg] |
| Full Idea: The fundamental thesis of real essentialism is that every finite material body has a twofold composition, being a compound of act and potency. ...Reality can take on new kinds of existence because there is a principle of potentiality inherent in reality. | |
| From: David S. Oderberg (Real Essentialism [2007], 4.1) | |
| A reaction: I take from this remark that the 'powers' discussed by Molnar and other scientific essentialists is roughly the same as 'potentiality' identified by Aristotle. |
| 12234 | Realism about possible worlds is circular, since it needs a criterion of 'possible' [Oderberg] |
| Full Idea: Any realist theory of possible worlds will be circular in its attempt to illuminate modality, for there has to be some criterion of what counts as a possible world. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: Seems right. At the very least, if we are going to rule out contradictory worlds as impossible (and is there a more obvious criterion?), we already need to understand 'impossible' in order to state that rule. |
| 12235 | Necessity of identity seems trivial, because it leaves out the real essence [Oderberg] |
| Full Idea: The necessity of identity carries the appearance of triviality, because it is the eviscerated contemporary essentialist form of a foundational real essentialist truth to the effect that every object has its own nature. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: I like this. Writers like Mackie and Forbes have to put the 'trivial' aspects of essence to one side, without ever seeing why there is such a problem. Real substantial essences have necessity of identity as a side-effect. |
| 12237 | Rigid designation has at least three essentialist presuppositions [Oderberg] |
| Full Idea: The rigid designator approach to essentialism has essentialist assumptions. ..The necessity of identity is built into the very conception of a rigid designator,..and Leibniz's Law is presupposed...and necessity of origin presupposes sufficiency of origin. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: [compressed. He cites Salmon 1981:196 for the last point] This sounds right. You feel happy to 'rigidly designate' something precisely because you think there is something definite and stable which can be designated. |
| 19061 | An explanation is often a deduction, but that may well beg the question [Dummett] |
| Full Idea: An explanation is often a deductive argument, with the fact needing explaining as its conclusion. ...But the conclusion is usually given in advance, and we may only believe the premisses because they plausibly explain the conclusion. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.296) | |
| A reaction: [compressed (Dummett's wordy prose cries out for it!)] I suppose this works better in mathematics, which is central to Dummett's interests. In the real world the puzzle is not usually logically implied by its explanation. |
| 19064 | Holism is not a theory of meaning; it is the denial that a theory of meaning is possible [Dummett] |
| Full Idea: In the sense of giving a model for the content of a sentence, its representative power, holism is not a theory of meaning; it is the denial that a theory of meaning is possible. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.309) | |
| A reaction: This will obviously be because sentences just don't have meaning in isolation, so their meaning can't be given in terms of the sentences. |
| 12245 | Essence is the source of a thing's characteristic behaviour [Oderberg] |
| Full Idea: In the traditional terminology, function follows essence. Essence just is the principle from which flows the characteristic behaviour of a thing. | |
| From: David S. Oderberg (Real Essentialism [2007], 2.1) | |
| A reaction: Hence essence must be identified if the behaviour is to be explained, and a successful identification of essence is the terminus of our explanations. But the essences must go down to the micro-level. Explain non-characteristic behaviour? |
| 12246 | What makes Parmenidean reality a One rather than a Many? [Oderberg] |
| Full Idea: Even if there were no multiplicity in unity - only a Parmenidean 'block' - still the question would arise as to what gave the amorphous lump its unity; by virtue of what would it be one rather than many? | |
| From: David S. Oderberg (Real Essentialism [2007], 3.1) | |
| A reaction: Which is prior, division or unification? If it was divided, he would ask what divided it. One of them must be primitive, so why not unity? If one big Unity is primitive, why could not lots of unities be primitive? Etc. |
| 12239 | The real essentialist is not merely a scientist [Oderberg] |
| Full Idea: It is incorrect to hold that the job of the real essentialist just is the job of the scientist. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.3) | |
| A reaction: Presumably scientific essentialism, while being firmly a branch of metaphysics, is meant to clarify the activities of science, and thereby be of some practical use. You can't beat knowing what it is you are trying to do. |
| 12243 | The reductionism found in scientific essentialism is mistaken [Oderberg] |
| Full Idea: The reductionism found in scientific essentialism is mistaken. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.4) | |
| A reaction: Oderberg's point is that essence doesn't just occur at the bottom of the hierarchy of kinds, but can exist on a macro-level, and need not be a concealed structure, as we see in the essence of a pile of stones. |