72 ideas
| 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? |
| 10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
| Full Idea: Three traditional names for rules are 'Simplification' (P from 'P and Q'), 'Addition' ('P or Q' from P), and 'Disjunctive Syllogism' (Q from 'P or Q' and 'not-P'). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 11004 | Necessity is provability in S4, and true in all worlds in S5 [Read] |
| Full Idea: In S4 necessity is said to be informal 'provability', and in S5 it is said to be 'true in every possible world'. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: It seems that the S4 version is proof-theoretic, and the S5 version is semantic. |
| 11018 | There are fuzzy predicates (and sets), and fuzzy quantifiers and modifiers [Read] |
| Full Idea: In fuzzy logic, besides fuzzy predicates, which define fuzzy sets, there are also fuzzy quantifiers (such as 'most' and 'few') and fuzzy modifiers (such as 'usually'). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) |
| 11011 | Same say there are positive, negative and neuter free logics [Read] |
| Full Idea: It is normal to classify free logics into three sorts; positive free logics (some propositions with empty terms are true), negative free logics (they are false), and neuter free logics (they lack truth-value), though I find this unhelpful and superficial. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) |
| 11020 | Realisms like the full Comprehension Principle, that all good concepts determine sets [Read] |
| Full Idea: Hard-headed realism tends to embrace the full Comprehension Principle, that every well-defined concept determines a set. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.8) | |
| A reaction: This sort of thing gets you into trouble with Russell's paradox (though that is presumably meant to be excluded somehow by 'well-defined'). There are lots of diluted Comprehension Principles. |
| 14187 | If logic is topic-neutral that means it delves into all subjects, rather than having a pure subject matter [Read] |
| Full Idea: The topic-neutrality of logic need not mean there is a pure subject matter for logic; rather, that the logician may need to go everywhere, into mathematics and even into metaphysics. | |
| From: Stephen Read (Formal and Material Consequence [1994], 'Logic') |
| 10986 | Not all validity is captured in first-order logic [Read] |
| Full Idea: We must recognise that first-order classical logic is inadequate to describe all valid consequences, that is, all cases in which it is impossible for the premisses to be true and the conclusion false. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: This is despite the fact that first-order logic is 'complete', in the sense that its own truths are all provable. |
| 10972 | The non-emptiness of the domain is characteristic of classical logic [Read] |
| Full Idea: The non-emptiness of the domain is characteristic of classical logic. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 11024 | Semantics must precede proof in higher-order logics, since they are incomplete [Read] |
| Full Idea: For the realist, study of semantic structures comes before study of proofs. In higher-order logic is has to, for the logics are incomplete. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.9) | |
| A reaction: This seems to be an important general observation about any incomplete system, such as Peano arithmetic. You may dream the old rationalist dream of starting from the beginning and proving everything, but you can't. Start with truth and meaning. |
| 10985 | We should exclude second-order logic, precisely because it captures arithmetic [Read] |
| Full Idea: Those who believe mathematics goes beyond logic use that fact to argue that classical logic is right to exclude second-order logic. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 14188 | Not all arguments are valid because of form; validity is just true premises and false conclusion being impossible [Read] |
| Full Idea: Belief that every valid argument is valid in virtue of form is a myth. ..Validity is a question of the impossibility of true premises and false conclusion for whatever reason, and some arguments are materially valid and the reason is not purely logical. | |
| From: Stephen Read (Formal and Material Consequence [1994], 'Logic') | |
| A reaction: An example of a non-logical reason is the transitive nature of 'taller than'. Conceptual connections are the usual example, as in 'it's red so it is coloured'. This seems to be a defence of the priority of semantic consequence in logic. |
| 14182 | If the logic of 'taller of' rests just on meaning, then logic may be the study of merely formal consequence [Read] |
| Full Idea: In 'A is taller than B, and B is taller than C, so A is taller than C' this can been seen as a matter of meaning - it is part of the meaning of 'taller' that it is transitive, but not of logic. Logic is now seen as the study of formal consequence. | |
| From: Stephen Read (Formal and Material Consequence [1994], 'Reduct') | |
| A reaction: I think I find this approach quite appealing. Obviously you can reason about taller-than relations, by putting the concepts together like jigsaw pieces, but I tend to think of logic as something which is necessarily implementable on a machine. |
| 14183 | Maybe arguments are only valid when suppressed premises are all stated - but why? [Read] |
| Full Idea: Maybe some arguments are really only valid when a suppressed premise is made explicit, as when we say that 'taller than' is a transitive concept. ...But what is added by making the hidden premise explicit? It cannot alter the soundness of the argument. | |
| From: Stephen Read (Formal and Material Consequence [1994], 'Suppress') |
| 10970 | A theory of logical consequence is a conceptual analysis, and a set of validity techniques [Read] |
| Full Idea: A theory of logical consequence, while requiring a conceptual analysis of consequence, also searches for a set of techniques to determine the validity of particular arguments. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10984 | Logical consequence isn't just a matter of form; it depends on connections like round-square [Read] |
| Full Idea: If classical logic insists that logical consequence is just a matter of the form, we fail to include as valid consequences those inferences whose correctness depends on the connections between non-logical terms (such as 'round' and 'square'). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: He suggests that an inference such as 'round, so not square' should be labelled as 'materially valid'. |
| 14184 | In modus ponens the 'if-then' premise contributes nothing if the conclusion follows anyway [Read] |
| Full Idea: A puzzle about modus ponens is that the major premise is either false or unnecessary: A, If A then B / so B. If the major premise is true, then B follows from A, so the major premise is redundant. So it is false or not needed, and contributes nothing. | |
| From: Stephen Read (Formal and Material Consequence [1994], 'Repres') | |
| A reaction: Not sure which is the 'major premise' here, but it seems to be saying that the 'if A then B' is redundant. If I say 'it's raining so the grass is wet', it seems pointless to slip in the middle the remark that rain implies wet grass. Good point. |
| 14186 | Logical connectives contain no information, but just record combination relations between facts [Read] |
| Full Idea: The logical connectives are useful for bundling information, that B follows from A, or that one of A or B is true. ..They import no information of their own, but serve to record combinations of other facts. | |
| From: Stephen Read (Formal and Material Consequence [1994], 'Repres') | |
| A reaction: Anyone who suggests a link between logic and 'facts' gets my vote, so this sounds a promising idea. However, logical truths have a high degree of generality, which seems somehow above the 'facts'. |
| 10973 | A theory is logically closed, which means infinite premisses [Read] |
| Full Idea: A 'theory' is any logically closed set of propositions, ..and since any proposition has infinitely many consequences, including all the logical truths, so that theories have infinitely many premisses. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: Read is introducing this as the essential preliminary to an account of the Compactness Theorem, which relates these infinite premisses to the finite. |
| 11007 | Quantifiers are second-order predicates [Read] |
| Full Idea: Quantifiers are second-order predicates. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) | |
| A reaction: [He calls this 'Frege's insight'] They seem to be second-order in Tarski's sense, that they are part of a metalanguage about the sentence, rather than being a part of the sentence. |
| 10978 | In second-order logic the higher-order variables range over all the properties of the objects [Read] |
| Full Idea: The defining factor of second-order logic is that, while the domain of its individual variables may be arbitrary, the range of the first-order variables is all the properties of the objects in its domain (or, thinking extensionally, of the sets objects). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: The key point is that the domain is 'all' of the properties. How many properties does an object have. You need to decide whether you believe in sparse or abundant properties (I vote for very sparse indeed). |
| 10971 | A logical truth is the conclusion of a valid inference with no premisses [Read] |
| Full Idea: Logical truth is a degenerate, or extreme, case of consequence. A logical truth is the conclusion of a valid inference with no premisses, or a proposition in the premisses of an argument which is unnecessary or may be suppressed. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10988 | Any first-order theory of sets is inadequate [Read] |
| Full Idea: Any first-order theory of sets is inadequate because of the Löwenheim-Skolem-Tarski property, and the consequent Skolem paradox. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: The limitation is in giving an account of infinities. |
| 10974 | Compactness is when any consequence of infinite propositions is the consequence of a finite subset [Read] |
| Full Idea: Classical logical consequence is compact, which means that any consequence of an infinite set of propositions (such as a theory) is a consequence of some finite subset of them. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10975 | Compactness does not deny that an inference can have infinitely many premisses [Read] |
| Full Idea: Compactness does not deny that an inference can have infinitely many premisses. It can; but classically, it is valid if and only if the conclusion follows from a finite subset of them. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10977 | Compactness blocks the proof of 'for every n, A(n)' (as the proof would be infinite) [Read] |
| Full Idea: Compact consequence undergenerates - there are intuitively valid consequences which it marks as invalid, such as the ω-rule, that if A holds of the natural numbers, then 'for every n, A(n)', but the proof of that would be infinite, for each number. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10976 | Compactness makes consequence manageable, but restricts expressive power [Read] |
| Full Idea: Compactness is a virtue - it makes the consequence relation more manageable; but it is also a limitation - it limits the expressive power of the logic. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: The major limitation is that wholly infinite proofs are not permitted, as in Idea 10977. |
| 11014 | Self-reference paradoxes seem to arise only when falsity is involved [Read] |
| Full Idea: It cannot be self-reference alone that is at fault. Rather, what seems to cause the problems in the paradoxes is the combination of self-reference with falsity. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.6) |
| 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. |
| 11025 | Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read] |
| Full Idea: Every potential infinity seems to suggest an actual infinity - e.g. generating successors suggests they are really all there already; cutting the line suggests that the point where the cut is made is already in place. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.8) | |
| A reaction: Finding a new gambit in chess suggests it was there waiting for us, but we obviously invented chess. Daft. |
| 10979 | Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read] |
| Full Idea: Second-order arithmetic is categorical - indeed, there is a single formula of second-order logic whose only model is the standard model ω, consisting of just the natural numbers, with all of arithmetic following. It is nevertheless incomplete. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: This is the main reason why second-order logic has a big fan club, despite the logic being incomplete (as well as the arithmetic). |
| 10980 | Second-order arithmetic covers all properties, ensuring categoricity [Read] |
| Full Idea: Second-order arithmetic can rule out the non-standard models (with non-standard numbers). Its induction axiom crucially refers to 'any' property, which gives the needed categoricity for the models. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10997 | Von Neumann numbers are helpful, but don't correctly describe numbers [Read] |
| Full Idea: The Von Neumann numbers have a structural isomorphism to the natural numbers - each number is the set of all its predecessors, so 2 is the set of 0 and 1. This helps proofs, but is unacceptable. 2 is not a set with two members, or a member of 3. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) |
| 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. |
| 11016 | Would a language without vagueness be usable at all? [Read] |
| Full Idea: We must ask whether a language without vagueness would be usable at all. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) | |
| A reaction: Popper makes a similar remark somewhere, with which I heartily agreed. This is the idea of 'spreading the word' over the world, which seems the right way of understanding it. |
| 11019 | Supervaluations say there is a cut-off somewhere, but at no particular place [Read] |
| Full Idea: The supervaluation approach to vagueness is to construe vague predicates not as ones with fuzzy borderlines and no cut-off, but as having a cut-off somewhere, but in no particular place. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) | |
| A reaction: Presumably you narrow down the gap by supervaluation, then split the difference to get a definite value. |
| 11012 | A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read] |
| Full Idea: A 'supervaluation' says a proposition is true if it is true in all classical extensions of the original partial valuation. Thus 'A or not-A' has no valuation for an empty name, but if 'extended' to make A true or not-true, not-A always has opposite value. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) |
| 11013 | Identities and the Indiscernibility of Identicals don't work with supervaluations [Read] |
| Full Idea: In supervaluations, the Law of Identity has no value for empty names, and remains so if extended. The Indiscernibility of Identicals also fails if extending it for non-denoting terms, where Fa comes out true and Fb false. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) |
| 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? |
| 10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
| Full Idea: The haecceitist (a neologism coined by Duns Scotus, pronounced 'hex-ee-it-ist', meaning literally 'thisness') believes that each thing has an individual essence, a set of properties which are essential to it. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: This seems to be a difference of opinion over whether a haecceity is a set of essential properties, or a bare particular. The key point is that it is unique to each entity. |
| 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. |
| 11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
| Full Idea: The equation of 'necessity' with 'true in every possible world' is known as the S5 conception, corresponding to the strongest of C.I.Lewis's five modal systems. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: Are the worlds naturally, or metaphysically, or logically possible? |
| 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. |
| 10989 | The standard view of conditionals is that they are truth-functional [Read] |
| Full Idea: The standard view of conditionals is that they are truth-functional, that is, that their truth-values are determined by the truth-values of their constituents. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.3) |
| 11017 | Some people even claim that conditionals do not express propositions [Read] |
| Full Idea: Some people even claim that conditionals do not express propositions. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) | |
| A reaction: See Idea 14283, where this appears to have been 'proved' by Lewis, and is not just a view held by some people. |
| 10992 | The point of conditionals is to show that one will accept modus ponens [Read] |
| Full Idea: The point of conditionals is to show that one will accept modus ponens. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.3) | |
| A reaction: [He attributes this idea to Frank Jackson] This makes the point, against Grice, that the implication of conditionals is not conversational but a matter of logical convention. See Idea 21396 for a very different view. |
| 14185 | Conditionals are just a shorthand for some proof, leaving out the details [Read] |
| Full Idea: Truth enables us to carry various reports around under certain descriptions ('what Iain said') without all the bothersome detail. Similarly, conditionals enable us to transmit a record of proof without its detail. | |
| From: Stephen Read (Formal and Material Consequence [1994], 'Repres') | |
| A reaction: This is his proposed Redundancy Theory of conditionals. It grows out of the problem with Modus Ponens mentioned in Idea 14184. To say that there is always an implied 'proof' seems a large claim. |
| 10983 | Knowledge of possible worlds is not causal, but is an ontology entailed by semantics [Read] |
| Full Idea: The modal Platonist denies that knowledge always depends on a causal relation. The reality of possible worlds is an ontological requirement, to secure the truth-values of modal propositions. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: [Reply to Idea 10982] This seems to be a case of deriving your metaphyics from your semantics, of which David Lewis seems to be guilty, and which strikes me as misguided. |
| 10982 | How can modal Platonists know the truth of a modal proposition? [Read] |
| Full Idea: If modal Platonism was true, how could we ever know the truth of a modal proposition? | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: I take this to be very important. Our knowledge of modal truths must depend on our knowledge of the actual world. The best answer seems to involve reference to the 'powers' of the actual world. A reply is in Idea 10983. |
| 10996 | Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read] |
| Full Idea: There are two main forms of actualism: reductionism, which seeks to construct possible worlds out of some more mundane material; and moderate realism, in which the actual concrete world is contrasted with abstract, but none the less real, possible worlds. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: I am a reductionist, as I do not take abstractions to be 'real' (precisely because they have been 'abstracted' from the things that are real). I think I will call myself a 'scientific modalist' - we build worlds from possibilities, discovered by science. |
| 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. |
| 10981 | A possible world is a determination of the truth-values of all propositions of a domain [Read] |
| Full Idea: A possible world is a complete determination of the truth-values of all propositions over a certain domain. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: Even if the domain is very small? Even if the world fitted the logic nicely, but was naturally impossible? |
| 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. |
| 11000 | If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read] |
| Full Idea: If each possible world constitutes a concrete reality, then no object can be present in more than one world - objects may have 'counterparts', but cannot be identical with them. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: This explains clearly why in Lewis's modal realist scheme he needs counterparts instead of rigid designation. Sounds like a slippery slope. If you say 'Humphrey might have won the election', who are you talking about? |
| 20653 | Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson] |
| Full Idea: There are six 'reductive levels' in science: social groups, (multicellular) living things, cells, molecules, atoms, and elementary particles. | |
| From: report of H.Putnam/P.Oppenheim (Unity of Science as a Working Hypothesis [1958]) by Peter Watson - Convergence 10 'Intro' | |
| A reaction: I have the impression that fields are seen as more fundamental that elementary particles. What is the status of the 'laws' that are supposed to govern these things? What is the status of space and time within this picture? |
| 10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
| Full Idea: Ways things might be are real, but only when abstracted from the actual way things are. They are brought out and distinguished by the mind, by abstraction, but are not dependent on mind for their existence. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: To me this just flatly contradicts itself. The idea that the mind can 'bring something out' by its operations, with the result being then accepted as part of reality is nonsense on stilts. What is real is the powers that make the possibilities. |
| 11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
| Full Idea: A problem with compositionality is negative existential propositions. If some of the terms of the proposition are empty, and don't refer, then compositionality implies that the whole will lack meaning too. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) | |
| A reaction: I don't agree. I don't see why compositionality implies holism about sentence-meaning. If I say 'that circular square is a psychopath', you understand the predication, despite being puzzled by the singular term. |
| 10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
| Full Idea: A proposition makes an object out of what is said or expressed by the utterance of a certain sort of sentence, namely, one in the indicative mood which makes sense and doesn't fail in its references. It can then be an object of thought and belief. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.1) | |
| A reaction: Nice, but two objections: I take it to be crucial to propositions that they eliminate ambiguities, and I take it that animals are capable of forming propositions. Read seems to regard them as fictions, but I take them to be brain events. |
| 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. |