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All the ideas for 'poems', 'Scientific Essentialism' and 'Thinking About Logic'

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78 ideas

1. Philosophy / E. Nature of Metaphysics / 4. Metaphysics as Science
Ontology should give insight into or an explanation of the world revealed by science [Ellis]
     Full Idea: A good ontology should provide insight into, or offer some kind of explanation of, the salient general features of the world that has been revealed to us by science.
     From: Brian Ellis (Scientific Essentialism [2001], Intro)
     A reaction: I think I agree with this. The difficulty is that the most fundamental level revealed by science is a quantum one, so if you take a reductionist view then your ontology is both crazy, and resting on things which are not understood.
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
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)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / a. Systems of modal logic
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.
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
Real possibility and necessity has the logic of S5, which links equivalence classes of worlds of the same kind [Ellis]
     Full Idea: The logic of real possibilities and necessities is just S5. This is because the accessibility relation for real possibilities links possible worlds of the same natural kind, which is an equivalence class.
     From: Brian Ellis (Scientific Essentialism [2001], 7.06)
     A reaction: Most people, except Nathan Salmon, agree with this. With full accessibility, you seem to take epistemological problems out of the system, and just focus on reality.
4. Formal Logic / E. Nonclassical Logics / 4. Fuzzy Logic
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)
4. Formal Logic / E. Nonclassical Logics / 6. Free Logic
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)
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / c. Logical sets
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.
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
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.
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
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)
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
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.
5. Theory of Logic / A. Overview of Logic / 8. Logic of Mathematics
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)
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
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)
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'.
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
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.
5. Theory of Logic / G. Quantification / 1. Quantification
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.
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
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).
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
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)
5. Theory of Logic / I. Semantics of Logic / 5. Extensionalism
Humean conceptions of reality drive the adoption of extensional logic [Ellis]
     Full Idea: A Humean conception of reality lies behind, and motivates, the development of extensional logics with extensional semantics.
     From: Brian Ellis (Scientific Essentialism [2001], 8.04)
     A reaction: His proposal seems to be that it rests on the vision of a domain of separated objects. The alternative view seems to be that it is mathematics, with its absolute equality between 'objects', which drives extensionalism.
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
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.
5. Theory of Logic / K. Features of Logics / 6. Compactness
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)
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)
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)
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.
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
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)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
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.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
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).
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)
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / g. Von Neumann numbers
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)
7. Existence / D. Theories of Reality / 10. Vagueness / d. Vagueness as linguistic
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.
7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness
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.
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)
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)
8. Modes of Existence / B. Properties / 1. Nature of Properties
The extension of a property is a contingent fact, so cannot be the essence of the property [Ellis]
     Full Idea: The extension of a property in any given world is just a contingent fact about that world; its extension is not the essence of the property.
     From: Brian Ellis (Scientific Essentialism [2001], 2.07)
     A reaction: The Quinean idea, common among logicians, that a predicate is just a set defined for some model, may be useful in the logic, but is preposterous as an account of what a property actually is in nature, even if the set covers possible worlds.
8. Modes of Existence / B. Properties / 5. Natural Properties
There is no property of 'fragility', as things are each fragile in a distinctive way [Ellis]
     Full Idea: There is no natural property of 'fragility'; glasses, parchments, ecosystems and spiders' webs are fragile in their own ways, but they have nothing intrinsic or structural in common.
     From: Brian Ellis (Scientific Essentialism [2001], 3.06)
     A reaction: This is important (and, I think, correct) because we are inclined to say that something is 'intrinsically' fragile, but that still isn't enough to identify a true property. Ellis wants universals to be involved, and even a nominalist must sort-of agree.
8. Modes of Existence / B. Properties / 6. Categorical Properties
Typical 'categorical' properties are spatio-temporal, such as shape [Ellis]
     Full Idea: The paradigmatically 'categorical' properties are spatio-temporal, depending on how things are distributed in space and time. Shape is the obvious example. ...Other examples are number, size and configuration.
     From: Brian Ellis (Scientific Essentialism [2001], 1.09)
     A reaction: I'm finding it very frustrating that this concept is much discussed in current philosophy of science (e.g. by Bird), but it is exceedingly hard to pin down any exact account of these 'categorical' properties, or even why they are so-called.
The property of 'being an electron' is not of anything, and only electrons could have it [Ellis]
     Full Idea: There is no property of being an electron. It could only be instantiated by electrons, so it does not seem genuine. And what is the thing that supposedly instantiates the property of being an electron?
     From: Brian Ellis (Scientific Essentialism [2001], 75,92), quoted by Stephen Mumford - Laws in Nature 7.3
     A reaction: I agree entirely. Bird launches an excellent attack on categorial properties.
8. Modes of Existence / B. Properties / 10. Properties as Predicates
'Being a methane molecule' is not a property - it is just a predicate [Ellis]
     Full Idea: In my view 'being a methane molecule' is not a property name, but a predicate that is constructed out of a natural kind name, and so pretends to name a property.
     From: Brian Ellis (Scientific Essentialism [2001], 2.03)
     A reaction: I can't tell you how strongly I agree with this. How long have you got? This is so incredibly right that... You get the idea. He observes that such properties cannot be instantiated 'in' anything.
8. Modes of Existence / C. Powers and Dispositions / 1. Powers
Causal powers must necessarily act the way they do [Ellis]
     Full Idea: There can be no question of a causal power's acting one way in one world and another way in a different world.
     From: Brian Ellis (Scientific Essentialism [2001], 1.12)
     A reaction: Perhaps the very core idea of scientific essentialism. It doesn't feel quite right that when you ask for the source of this necessity, you are only told that it is necessary for the very identity of a power. The truth is that it is a primitive of nature.
Causal powers are often directional (e.g. centripetal, centrifugal, circulatory) [Ellis]
     Full Idea: Causal powers are often directional. For example, they may be centripetal, centrifugal, or circulatory.
     From: Brian Ellis (Scientific Essentialism [2001], 3.11)
     A reaction: The examples all seem to raise a few questions, about whether the directionality arises from the context, rather than from the intrinsic power.
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
Basic powers may not be explained by structure, if at the bottom level there is no structure [Ellis]
     Full Idea: It may be that the most fundamental things have no structure, and therefore no structure in virtue of which they have the powers they have.
     From: Brian Ellis (Scientific Essentialism [2001], Intro)
     A reaction: Maybe the world has inexplicable powers, so there is a God? It seems obvious that there will be no explanation of the 'lowest level' of reality, and also obvious (to me and Leibniz, anyway) that this lowest level has to be active.
Maybe dispositions can be explained by intrinsic properties or structures [Ellis]
     Full Idea: One view is that there must be an intrinsic property or structure in virtue of which a given thing has the behavioural disposition in question.
     From: Brian Ellis (Scientific Essentialism [2001], 3.06)
     A reaction: [He cites Prior, Pargetter,Jackson 1982] A key question in the metaphysics of nature - whether dispositions should be taken as primitive, or whether we should try to explain them in other terms. I take powers and dispositions to be prior to properties.
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / a. Dispositions
The most fundamental properties of nature (mass, charge, spin ...) all seem to be dispositions [Ellis]
     Full Idea: The properties of the most fundamental things in nature, including mass, charge, spin, and the like, would all appear to be dispositional.
     From: Brian Ellis (Scientific Essentialism [2001], 3.05)
     A reaction: This goes with the Leibnizian claim that the most fundamental features of nature must be active in character.
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / b. Dispositions and powers
A causal power is a disposition to produce forces [Ellis]
     Full Idea: A causal power is a disposition of something to produce forces of a certain kind.
     From: Brian Ellis (Scientific Essentialism [2001], 3.09)
     A reaction: Hence when Leibniz was putting all his emphasis on the origin of the forces in nature, he was referring to exactly what we mean by 'powers'. From Ellis's formulation, I take powers to be more basic than dispositions. Does he realise this?
Powers are dispositions of the essences of kinds that involve them in causation [Ellis]
     Full Idea: The causal powers of an object are the dispositional properties of that object that are the real essences of the natural kinds of processes that involve that object in the role of cause.
     From: Brian Ellis (Scientific Essentialism [2001], 3.11)
     A reaction: This is Ellis's formal definition at the end of his discussion of causal powers. He only seems to allow powers to the kind rather than to the individual. How do we account for the causal powers of unique genius? I say the powers are the essences.
8. Modes of Existence / D. Universals / 1. Universals
There are 'substantive' (objects of some kind), 'dynamic' (events of some kind) and 'property' universals [Ellis]
     Full Idea: Three categories of universals: 'substantive' universals have instances that are members of natural kinds of objects or substances; 'dynamic' universals are kinds of events or processes; 'property' universals are tropes of real properties or relations.
     From: Brian Ellis (Scientific Essentialism [2001], 1.01)
     A reaction: I would want to distinguish real properties from relations. It is important to remember that an object can traditionally instantiate a universal, and that they aren't just properties.
Universals are all types of natural kind [Ellis]
     Full Idea: The various kinds of universals are all natural kinds of one sort or another.
     From: Brian Ellis (Scientific Essentialism [2001], 1.01)
     A reaction: This doesn't sound right. What about the universals of mathematics, or universals which are a matter of social or linguistic convention? I think Ellis is trying to hijack the word 'universal' in response to Armstrong's more idealistic account.
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
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.
9. Objects / D. Essence of Objects / 3. Individual Essences
Scientific essentialism doesn't really need Kripkean individual essences [Ellis]
     Full Idea: My current view is that individual essences (about which Kripke's essentialism has a lot to say) do not matter much from the point of view of a scientific essentialist.
     From: Brian Ellis (Scientific Essentialism [2001], Intro)
     A reaction: [Kripke parenthesis on p.54] Presumably this is because science is only committed to dealing in generalities, and so natural kinds are needed for such things. I'm inclined to regard individual essences as prior in the pure ontology of the thing.
9. Objects / D. Essence of Objects / 15. Against Essentialism
The old idea that identity depends on essence and behaviour is rejected by the empiricists [Ellis]
     Full Idea: The old Aristotelian idea that the identity of a thing might depend on its essential nature, which would dispose it to behave in certain ways, is firmly rejected by empiricists.
     From: Brian Ellis (Scientific Essentialism [2001], 1.10)
     A reaction: Ellis is accusing empiricists of having a falsely passive concept of objects. This dispute is best captured in the disagreement between Locke and Leibniz on the subject.
10. Modality / A. Necessity / 2. Nature of Necessity
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?
10. Modality / A. Necessity / 3. Types of Necessity
Necessities are distinguished by their grounds, not their different modalities [Ellis]
     Full Idea: Strictly speaking, the distinction between two brands of necessity is one of grounds, rather than modality.
     From: Brian Ellis (Scientific Essentialism [2001], 1.06)
     A reaction: This idea I associate with Kit Fine. I like it, because it allows 'necessity' to be a univocal concept, which seems right to me. The types of necessity arise from types of things which already occur in our ontology.
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
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)
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.
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.
10. Modality / C. Sources of Modality / 6. Necessity from Essence
Individual essences necessitate that individual; natural kind essences necessitate kind membership [Ellis]
     Full Idea: There are necessities grounded in the individual real essences of things, and necessities grounded in the natural kind essences of things. In the first case, without the property it isn't that individual, and in the second it isn't a member of that kind.
     From: Brian Ellis (Scientific Essentialism [2001], Intro)
     A reaction: This is the distinction we must hang onto to avoid a huge amount of confusion in this territory. I just say that ceasing to be that individual will presumably entail ceasing to be that kind, but not necessarily vice versa, so individual essences rule.
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
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.
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
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.
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
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.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / c. Worlds as propositions
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?
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
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?
14. Science / C. Induction / 3. Limits of Induction
If events are unconnected, then induction cannot be solved [Ellis]
     Full Idea: If one believes, as Hume did, that all events are loose and separate, then the problem of induction is probably insoluble.
     From: Brian Ellis (Scientific Essentialism [2001], 8.09)
     A reaction: This points to the essentialist solution of induction - that we can genuinely derive inductive truths if we can inductively identify the essences which give rise to the necessities of further cases. I take that to be a correct account.
14. Science / D. Explanation / 2. Types of Explanation / c. Explanations by coherence
Good explanations unify [Ellis]
     Full Idea: An acceptable explanation must have some unifying power.
     From: Brian Ellis (Scientific Essentialism [2001], 3.11)
     A reaction: There is a tension here, between the particular and the general. If I say 'why did the building collapse' and you say 'gravity', you have certainly got a unifying explanation, but we want something narrower.
14. Science / D. Explanation / 2. Types of Explanation / i. Explanations by mechanism
Explanations of particular events are not essentialist, as they don't reveal essential structures [Ellis]
     Full Idea: Explanations of particular events in history, geology, or evolution, are causal explanations, requiring belief in some causal mechanisms. But they are not essentialist explanations because they do not seek to lay bare the essential structure of anything.
     From: Brian Ellis (Scientific Essentialism [2001], 4.05)
     A reaction: The explanation might be two-stage, as when we explain an earthquake by a plate boundary rupture, which is in turn explained by a theory of plate techtonics. The relationship between mechanistic and essentialist explanation needs study.
14. Science / D. Explanation / 2. Types of Explanation / k. Explanations by essence
To give essentialist explanations there have to be natural kinds [Ellis]
     Full Idea: There can be no essentialist explanations constructed in any field where the subject matter is not naturally divided into kinds.
     From: Brian Ellis (Scientific Essentialism [2001], Intro)
     A reaction: A crux. I like individual essences, such as the character of a particular person. However, Ellis may be right, since while we may identify an individual essence as the source of a behaviour, we may not then be able to give any 'explanation'.
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
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.
15. Nature of Minds / C. Capacities of Minds / 6. Idealisation
The point of models in theories is not to idealise, but to focus on what is essential [Ellis]
     Full Idea: Most model theories abstract from reality in order to focus on the essential nature of some kind of process or system of relations. ... The point of idealizing in this case is not to simplify, but to eliminate what is not essential.
     From: Brian Ellis (Scientific Essentialism [2001], 4.03)
     A reaction: I like this idea a lot. It is where scientific essentialism cashes out in actual scientific practice. Ellis's example is the idealised Carnot heat engine, which never can exist, but which captures what is essential about the process.
19. Language / C. Assigning Meanings / 4. Compositionality
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.
19. Language / D. Propositions / 1. Propositions
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.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
Nomos is king [Pindar]
     Full Idea: Nomos is king.
     From: Pindar (poems [c.478 BCE], S 169), quoted by Thomas Nagel - The Philosophical Culture
     A reaction: This seems to be the earliest recorded shot in the nomos-physis wars (the debate among sophists about moral relativism). It sounds as if it carries the full relativist burden - that all that matters is what has been locally decreed.
26. Natural Theory / B. Natural Kinds / 3. Knowing Kinds
There might be uninstantiated natural kinds, such as transuranic elements which have never occurred [Ellis]
     Full Idea: There are reasons to believe that there are natural kinds that might never be instantiated, such as a transuranic element, capable of existing for some fraction of a second, but which has never actually existed anywhere.
     From: Brian Ellis (Scientific Essentialism [2001], 2.05)
     A reaction: He cautiously claims that kinds are ontologically prior to their individual members. I would say that there is no natural kind of the type that he describes. He says you have at least some grounds for predicting what kinds are possible.
26. Natural Theory / B. Natural Kinds / 4. Source of Kinds
Natural kinds are distinguished by resting on essences [Ellis]
     Full Idea: Natural kinds are distinguished from other sorts of things by their associations with essential properties and real essences.
     From: Brian Ellis (Scientific Essentialism [2001], 1.02)
     A reaction: I don't think I agree with this. I rest my notion of natural kind on the elementary realising that to know all about this kind you only have to examine one sample of it, as in the Upanishads. The source of such a phenomenon is an open question.
26. Natural Theory / B. Natural Kinds / 7. Critique of Kinds
If there are borderline cases between natural kinds, that makes them superficial [Ellis]
     Full Idea: There cannot be any borderline cases between the real essences of different natural kinds because, if there were, the distinctions between the kinds would be superficial, like the blue/green distinction.
     From: Brian Ellis (Scientific Essentialism [2001], 1.05)
     A reaction: His particular target here is biological natural kinds, in which he doesn't believe, because they blur across time, in the evolutionary process. Personally I am inclined to relax the notion of a natural kind, otherwise they are too basic to explain.
26. Natural Theory / D. Laws of Nature / 1. Laws of Nature
Laws don't exist in the world; they are true of the world [Ellis]
     Full Idea: Laws are not things that exist in the world; they are things that are true of the world.
     From: Brian Ellis (Scientific Essentialism [2001], 3.09)
     A reaction: I'm happy with this formulation. The one to get rid of is the idea of laws which could precede creation of the universe, and survive its demise. That might be possible, but we have absolutely no grounds for the claim. Humeans ought to agree.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / a. Scientific essentialism
A proton must have its causal role, because without it it wouldn't be a proton [Ellis]
     Full Idea: I assume it is metaphysically impossible for a proton to have a different causal role, ...which is plausible because a proton would appear to have no identity at all apart from its role in causal processes.
     From: Brian Ellis (Scientific Essentialism [2001], Intro)
     A reaction: This seems to be a key idea in scientific essentialism, which links essentialism of identity with essentialism in the laws of nature. Could a proton become not-quite-a-proton?
What is most distinctive of scientific essentialism is regarding processes as natural kinds [Ellis]
     Full Idea: What is most distinctive of the scientific version of essentialism is that scientific essentialists are realists about natural kinds of processes, as well as natural kinds of objects and substances.
     From: Brian Ellis (Scientific Essentialism [2001], 1.11)
     A reaction: I'm not sure whether other scientific essentialists would agree with this, but I am happy to go along with it. A process like melting or sublimation seems to be a standard widespread phenomenon which is always intrinsically the same, as kinds must be.
Scientific essentialism is more concerned with explanation than with identity (Locke, not Kripke) [Ellis]
     Full Idea: Scientific essentialism is less concerned with questions of identity, and more with questions of explanation, than is the essentialism of Aristotle or of Kripke. It is closest to the kind of essentialism described by Locke.
     From: Brian Ellis (Scientific Essentialism [2001], 1.12)
     A reaction: Locke is popularly held to be anti-essentialist, but that is only because of his epistemological problems. I think Ellis is here misreading Aristotle, and I would ally Aristotle, Locke (cautiously), Leibniz, Ellis and Fine against Kripkeans on this one.
The ontological fundamentals are dispositions, and also categorical (spatio-temporal and structural) properties [Ellis]
     Full Idea: We do not claim, as some do, that fundamental dispositional properties are the ontological basis of all properties. On the contrary, there are equally fundamental categorical properties - for example, spatio-temporal relations and structures.
     From: Brian Ellis (Scientific Essentialism [2001], 3.09)
     A reaction: The source of disagreement between Bird and Ellis. Bird denies the existence of 'categorical properties'. I think I am with Bird. Space and time are as much part of the given as the elements, and then categorical properties result from dispositions.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / b. Scientific necessity
A primary aim of science is to show the limits of the possible [Ellis]
     Full Idea: Scientific essentialists hold that one of the primary aims of science is to define the limits of the possible.
     From: Brian Ellis (Scientific Essentialism [2001], 7.06)
     A reaction: I like this. It breaks down into the study of modal profiles, and it can work for abstracta as well as for the physical world. It even covers the study of character, and you could say that it is the subject matter of Jane Austen.