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54 ideas

1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
If you know what it is, investigation is pointless. If you don't, investigation is impossible [Armstrong]
     Full Idea: Paradox of Analysis:if we ask what sort of thing an X is, then either we know what an X is or we do not. If we know then there is no need to ask the question. If we do not know then there is no way to begin the investigation. It's pointless or impossible
     From: David M. Armstrong (What is a Law of Nature? [1983], 01.2)
     A reaction: [G.E. Moore is the source of this, somewhere] Plato worried that to get to know something you must already know it. Solving this requires the concept of a 'benign' circularity.
3. Truth / F. Semantic Truth / 2. Semantic Truth
While true-in-a-model seems relative, true-in-all-models seems not to be [Reck/Price]
     Full Idea: While truth can be defined in a relative way, as truth in one particular model, a non-relative notion of truth is implied, as truth in all models.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: [The article is actually discussing arithmetic] This idea strikes me as extremely important. True-in-all-models is usually taken to be tautological, but it does seem to give a more universal notion of truth. See semantic truth, Tarski, Davidson etc etc.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
ZFC set theory has only 'pure' sets, without 'urelements' [Reck/Price]
     Full Idea: In standard ZFC ('Zermelo-Fraenkel with Choice') set theory we deal merely with pure sets, not with additional urelements.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: The 'urelements' would the actual objects that are members of the sets, be they physical or abstract. This idea is crucial to understanding philosophy of mathematics, and especially logicism. Must the sets exist, just as the urelements do?
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
Three types of variable in second-order logic, for objects, functions, and predicates/sets [Reck/Price]
     Full Idea: In second-order logic there are three kinds of variables, for objects, for functions, and for predicates or sets.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: It is interesting that a predicate seems to be the same as a set, which begs rather a lot of questions. For those who dislike second-order logic, there seems nothing instrinsically wicked in having variables ranging over innumerable multi-order types.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
'Analysis' is the theory of the real numbers [Reck/Price]
     Full Idea: 'Analysis' is the theory of the real numbers.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: 'Analysis' began with the infinitesimal calculus, which later built on the concept of 'limit'. A continuum of numbers seems to be required to make that work.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
Mereological arithmetic needs infinite objects, and function definitions [Reck/Price]
     Full Idea: The difficulties for a nominalistic mereological approach to arithmetic is that an infinity of physical objects are needed (space-time points? strokes?), and it must define functions, such as 'successor'.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: Many ontologically austere accounts of arithmetic are faced with the problem of infinity. The obvious non-platonist response seems to be a modal or if-then approach. To postulate infinite abstract or physical entities so that we can add 3 and 2 is mad.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Peano Arithmetic can have three second-order axioms, plus '1' and 'successor' [Reck/Price]
     Full Idea: A common formulation of Peano Arithmetic uses 2nd-order logic, the constant '1', and a one-place function 's' ('successor'). Three axioms then give '1 is not a successor', 'different numbers have different successors', and induction.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: This is 'second-order' Peano Arithmetic, though it is at least as common to formulate in first-order terms (only quantifying over objects, not over properties - as is done here in the induction axiom). I like the use of '1' as basic instead of '0'!
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Set-theory gives a unified and an explicit basis for mathematics [Reck/Price]
     Full Idea: The merits of basing an account of mathematics on set theory are that it allows for a comprehensive unified treatment of many otherwise separate branches of mathematics, and that all assumption, including existence, are explicit in the axioms.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: I am forming the impression that set-theory provides one rather good model (maybe the best available) for mathematics, but that doesn't mean that mathematics is set-theory. The best map of a landscape isn't a landscape.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Structuralism emerged from abstract algebra, axioms, and set theory and its structures [Reck/Price]
     Full Idea: Structuralism has emerged from the development of abstract algebra (such as group theory), the creation of axiom systems, the introduction of set theory, and Bourbaki's encyclopaedic survey of set theoretic structures.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: In other words, mathematics has gradually risen from one level of abstraction to the next, so that mathematical entities like points and numbers receive less and less attention, with relationships becoming more prominent.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / b. Varieties of structuralism
Relativist Structuralism just stipulates one successful model as its arithmetic [Reck/Price]
     Full Idea: Relativist Structuralism simply picks one particular model of axiomatised arithmetic (i.e. one particular interpretation that satisfies the axioms), and then stipulates what the elements, functions and quantifiers refer to.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: The point is that a successful model can be offered, and it doesn't matter which one, like having any sort of aeroplane, as long as it flies. I don't find this approach congenial, though having a model is good. What is the essence of flight?
There are 'particular' structures, and 'universal' structures (what the former have in common) [Reck/Price]
     Full Idea: The term 'structure' has two uses in the literature, what can be called 'particular structures' (which are particular relational systems), but also what can be called 'universal structures' - what particular systems share, or what they instantiate.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §6)
     A reaction: This is a very helpful distinction, because it clarifies why (rather to my surprise) some structuralists turn out to be platonists in a new guise. Personal my interest in structuralism has been anti-platonist from the start.
Pattern Structuralism studies what isomorphic arithmetic models have in common [Reck/Price]
     Full Idea: According to 'pattern' structuralism, what we study are not the various particular isomorphic models of arithmetic, but something in addition to them: a corresponding pattern.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §7)
     A reaction: Put like that, we have to feel a temptation to wield Ockham's Razor. It's bad enough trying to give the structure of all the isomorphic models, without seeking an even more abstract account of underlying patterns. But patterns connect to minds..
There are Formalist, Relativist, Universalist and Pattern structuralism [Reck/Price]
     Full Idea: There are four main variants of structuralism in the philosophy of mathematics - formalist structuralism, relativist structuralism, universalist structuralism (with modal variants), and pattern structuralism.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §9)
     A reaction: I'm not sure where Chihara's later book fits into this, though it is at the nominalist end of the spectrum. Shapiro and Resnik do patterns (the latter more loosely); Hellman does modal universalism; Quine does the relativist version. Dedekind?
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / c. Nominalist structuralism
Formalist Structuralism says the ontology is vacuous, or formal, or inference relations [Reck/Price]
     Full Idea: Formalist Structuralism endorses structural methodology in mathematics, but rejects semantic and metaphysical problems as either meaningless, or purely formal, or as inference relations.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §3)
     A reaction: [very compressed] I find the third option fairly congenial, certainly in preference to rather platonist accounts of structuralism. One still needs to distinguish the mathematical from the non-mathematical in the inference relations.
Maybe we should talk of an infinity of 'possible' objects, to avoid arithmetic being vacuous [Reck/Price]
     Full Idea: It is tempting to take a modal turn, and quantify over all possible objects, because if there are only a finite number of actual objects, then there are no models (of the right sort) for Peano Arithmetic, and arithmetic is vacuously true.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: [compressed; Geoffrey Hellman is the chief champion of this view] The article asks whether we are not still left with the puzzle of whether infinitely many objects are possible, instead of existent.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / d. Platonist structuralism
Universalist Structuralism is based on generalised if-then claims, not one particular model [Reck/Price]
     Full Idea: Universalist Structuralism is a semantic thesis, that an arithmetical statement asserts a universal if-then statement. We build an if-then statement (using quantifiers) into the structure, and we generalise away from any one particular model.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: There remains the question of what is distinctively mathematical about the highly generalised network of inferences that is being described. Presumable the axioms capture that, but why those particular axioms? Russell is cited as an originator.
Universalist Structuralism eliminates the base element, as a variable, which is then quantified out [Reck/Price]
     Full Idea: Universalist Structuralism is eliminativist about abstract objects, in a distinctive form. Instead of treating the base element (say '1') as an ambiguous referring expression (the Relativist approach), it is a variable which is quantified out.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: I am a temperamental eliminativist on this front (and most others) so this is tempting. I am also in love with the concept of a 'variable', which I take to be utterly fundamental to all conceptual thought, even in animals, and not just a trick of algebra.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
The existence of an infinite set is assumed by Relativist Structuralism [Reck/Price]
     Full Idea: Relativist Structuralism must first assume the existence of an infinite set, otherwise there would be no model to pick, and arithmetical terms would have no reference.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: See Idea 10169 for Relativist Structuralism. They point out that ZFC has an Axiom of Infinity.
7. Existence / D. Theories of Reality / 8. Facts / b. Types of fact
Negative facts are supervenient on positive facts, suggesting they are positive facts [Armstrong]
     Full Idea: Negative facts appear to be supervenient upon the positive facts, which suggests that they are nothing more than the positive facts.
     From: David M. Armstrong (What is a Law of Nature? [1983], 10.3)
8. Modes of Existence / A. Relations / 4. Formal Relations / a. Types of relation
Nothing is genuinely related to itself [Armstrong]
     Full Idea: I believe that nothing is genuinely related to itself.
     From: David M. Armstrong (What is a Law of Nature? [1983], 10.7)
8. Modes of Existence / B. Properties / 1. Nature of Properties
All instances of some property are strictly identical [Armstrong]
     Full Idea: A property ...is something which is strictly identical, strictly the same, in all its different instances.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.2)
     A reaction: Some is gravitation one property, or an infinity of properties, for each of its values? What is the same between objects of different mass. I sort of believe in all the masses, but I'm not sure what 'mass' is. Abstraction, say I.
8. Modes of Existence / B. Properties / 6. Categorical Properties
Armstrong holds that all basic properties are categorical [Armstrong, by Ellis]
     Full Idea: I am against Armstrong's strong categoricalism, that is, the thesis that all basic properties are categorical.
     From: report of David M. Armstrong (What is a Law of Nature? [1983]) by Brian Ellis - The Metaphysics of Scientific Realism 3
     A reaction: I certainly agree with this, as I cannot see where the power would come from to get the whole thing off the ground. Armstrong depends on universals to necessitate what happens, which I find very peculiar.
8. Modes of Existence / C. Powers and Dispositions / 7. Against Powers
Actualism means that ontology cannot contain what is merely physically possible [Armstrong]
     Full Idea: Actualism ...debars us from admitting into our ontology the merely possible, not only the merely logically possible, but also the merely physically possible.
     From: David M. Armstrong (What is a Law of Nature? [1983], 01.3)
     A reaction: This is the big metaphysical question for fans (like myself) of 'powers' in nature. Armstrong declares himself an Actualist. I take it as obvious that the actual world contains powers, but how are we to characterise them?
Dispositions exist, but their truth-makers are actual or categorical properties [Armstrong]
     Full Idea: It is not denied that statements attributing dispositions and/or powers to objects are often true. But the truth-makers or ontological ground for such statements must always be found in the actual, or categorical, properties of the objects involved.
     From: David M. Armstrong (What is a Law of Nature? [1983], 01.3)
     A reaction: This is the big debate in the topic of powers. I love powers, but you always think there must be 'something' which has the power. Could reality entirely consist of powers? See Fetzer.
If everything is powers there is a vicious regress, as powers are defined by more powers [Armstrong]
     Full Idea: I believe reducing all universals to powers is involved in vicious regress. The power is what it is by the sort of actualisations it gives rise to in suitable sorts of circumstances. But they themselves can be nothing but powers...
     From: David M. Armstrong (What is a Law of Nature? [1983], 08.3)
     A reaction: [compressed wording] I don't see this problem. Anything postulated as fundamental is going to be baffling. Why are categorical properties superior to powers? Postulate basic powers (or basic empowered stuff), then build up.
8. Modes of Existence / D. Universals / 1. Universals
Universals are just the repeatable features of a world [Armstrong]
     Full Idea: Universals can be brought into the spatio-temporal world, becoming simply the repeatable features of that world.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.2)
     A reaction: I wish Armstrong wouldn't use the word 'universal', which has so much historical baggage. The world obviously has repeatable features, but does that mean that our ontology must include things called 'features'? Hm.
8. Modes of Existence / D. Universals / 2. Need for Universals
Realist regularity theories of laws need universals, to pick out the same phenomena [Armstrong]
     Full Idea: A Realistic version of a Regularity theory of laws will have to postulate universals. How else will it be possible to say that the different instances of a certain uniformity are all instances of objectively the same phenomenon?
     From: David M. Armstrong (What is a Law of Nature? [1983], 02.4)
     A reaction: I disagree. We may (or may not) need properties, but they can be have a range. We just need stable language. We use one word 'red', even when the shade of redness varies. Non-realists presumably refer to sense-data.
8. Modes of Existence / D. Universals / 3. Instantiated Universals
Universals are abstractions from their particular instances [Armstrong, by Lewis]
     Full Idea: Armstrong takes universals generally, and structural universals along with the rest, to be abstractions from their particular instances.
     From: report of David M. Armstrong (What is a Law of Nature? [1983], p.83-4) by David Lewis - Against Structural Universals 'The pictorial'
     A reaction: To me, 'abstracted' implies a process of human psychology, a way of thinking about the instances. I don't see how there can be an 'abstracted' relation which is a part of the external world. That makes his laws of nature human creations.
Past, present and future must be equally real if universals are instantiated [Armstrong]
     Full Idea: Past, present and future I take to be all and equally real. A universal need not be instantiated now.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.2)
     A reaction: This is the price you must pay for saying that you only believe in universals which are instantiated.
Universals are abstractions from states of affairs [Armstrong]
     Full Idea: Universals are abstractions from states of affairs.
     From: David M. Armstrong (What is a Law of Nature? [1983], 7)
     A reaction: I'm getting confused about Armstrong's commitments. He bases his whole theory on the existence of universals (repeatable features), but now says those are 'abstracted' from something else. Abstracted by us?
8. Modes of Existence / E. Nominalism / 6. Mereological Nominalism
A nominalist might avoid abstract objects by just appealing to mereological sums [Reck/Price]
     Full Idea: One way for a nominalist to reject appeal to all abstract objects, including sets, is to only appeal to nominalistically acceptable objects, including mereological sums.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: I'm suddenly thinking that this looks very interesting and might be the way to go. The issue seems to be whether mereological sums should be seen as constrained by nature, or whether they are unrestricted. See Mereology in Ontology...|Intrinsic Identity.
9. Objects / A. Existence of Objects / 5. Individuation / b. Individuation by properties
It is likely that particulars can be individuated by unique conjunctions of properties [Armstrong]
     Full Idea: For each particular it is likely that there exists at least one individuating conjunction of properties, that is, a conjunction of properties such that the particular instantiates this conjunction and nothing else does.
     From: David M. Armstrong (What is a Law of Nature? [1983], 02.3)
     A reaction: Armstrong commits to a famous Leibniz view, but I don't see his grounds for it. There is nothing incoherent about nature churning out perfect replicas of things, such as quarks and electrons. Would we care if two pens were perfectly identical?
9. Objects / F. Identity among Objects / 5. Self-Identity
The identity of a thing with itself can be ruled out as a pseudo-property [Armstrong]
     Full Idea: There is reason to rule out as pseudo-properties such things as the identity of a thing with itself.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.2)
     A reaction: Good on you, David.
10. Modality / B. Possibility / 5. Contingency
The necessary/contingent distinction may need to recognise possibilities as real [Armstrong]
     Full Idea: It may be that the necessary/contingent distinction is tied to a metaphysics which recognises possibility as a real something wider than actuality.
     From: David M. Armstrong (What is a Law of Nature? [1983], 11.2)
     A reaction: Armstrong responds by trying to give an account of possibility in terms of 'combinations' from actuality. I think powers offer a much better strategy.
14. Science / C. Induction / 3. Limits of Induction
Induction aims at 'all Fs', but abduction aims at hidden or theoretical entities [Armstrong]
     Full Idea: Many philosophers of science have distinguished between 'simple induction' - the argument from observed Fs to all Fs - and the argument to hidden or theoretical entities (Peirce's 'abduction').
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.7)
     A reaction: 'Abduction' is (roughly) the same is inference to the best explanation, of which I am a great fan.
14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem
Science suggests that the predicate 'grue' is not a genuine single universal [Armstrong]
     Full Idea: It is plausible to say, on the basis of total science, that 'grue' is a predicate to which no genuine, that is, unitary, universal corresponds.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.7)
Unlike 'green', the 'grue' predicate involves a time and a change [Armstrong]
     Full Idea: The predicate 'grue' involves essential reference to a particular time, which 'green' does not. Also on the 'grue' hypothesis a change occurs in emeralds in a way that change does not occur on the 'green' hypothesis.
     From: David M. Armstrong (What is a Law of Nature? [1983], 04.5)
     A reaction: I'm inclined to think that comparing 'grue' with 'green' is a category mistake. 'Grue' is a behaviour. Armstrong says this is no objection, because Goodman's argument is purely formal.
14. Science / C. Induction / 5. Paradoxes of Induction / b. Raven paradox
The raven paradox has three disjuncts, confirmed by confirming any one of them [Armstrong]
     Full Idea: We could rewrite the generalisation as For all x, ((x is a raven and x is black) v (x is not a raven and x is black) v (x is not a raven and x is not black)). Instances of any one of the three disjuncts will do as confirmation.
     From: David M. Armstrong (What is a Law of Nature? [1983], 04.3)
     A reaction: A nice clarification.
14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
A good reason for something (the smoke) is not an explanation of it (the fire) [Armstrong]
     Full Idea: A good reason for P is not necessarily an explanation of P. The presence of smoke is a good reason for thinking that fire is present. But it is not an explanation of the presence of fire.
     From: David M. Armstrong (What is a Law of Nature? [1983], 04.2)
     A reaction: This may be an equivocation on 'the reason for'. Smoke is a reason for thinking there is a fire, but no one would propose it as a reason for the fire. If the reason for the fire was arson, that would seem to explain it as well.
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
To explain observations by a regular law is to explain the observations by the observations [Armstrong]
     Full Idea: Given the Regularity theory, the explanatory element seems to vanish. For to say that all the observed Fs are Gs because all the Fs are Gs involves explaining the observations in terms of themselves.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.7)
     A reaction: This point cries out, it is so obvious (once spotted). Tigers are ferocious because all tigers are ferocious (see?).
14. Science / D. Explanation / 3. Best Explanation / a. Best explanation
Best explanations explain the most by means of the least [Armstrong]
     Full Idea: The best explanation explains the most by means of the least. Explanation unifies.
     From: David M. Armstrong (What is a Law of Nature? [1983], 05.4)
     A reaction: To get unification, you need to cite the diversity of what is explained, and not the mere quantity. The force of gravity unifies because it applies to such a diversity of things.
18. Thought / E. Abstraction / 1. Abstract Thought
Each subject has an appropriate level of abstraction [Armstrong]
     Full Idea: To every subject, its appropriate level of abstraction.
     From: David M. Armstrong (What is a Law of Nature? [1983], 01.2)
     A reaction: Mathematics rises through many levels of abstraction. Economics can be very concrete or very abstract. It think it is clearer to talk of being 'general', rather than 'abstract'.
23. Ethics / A. Egoism / 2. Hedonism
All inventions of the mind aim at pleasure, and those that don't are worthless [Metrodorus of Lamp., by Plutarch]
     Full Idea: Metrodorus says that all the wonderful, ingenious and brilliant inventions of the mind have been contrived for the sake of pleasure of the flesh or for the sake of looking forward to it, and any accomplishment not leading to this end is worthless.
     From: report of Metrodorus (Lamp) (fragments/reports [c.291 BCE], Fr 6) by Plutarch - 74: Reply to Colotes §1125
     A reaction: It is very hard to think of counterexamples! Would anyone bother to work out the theorems of number theory if they didn't enjoy doing it? Would any sensible person make great sacrifices if they didn't think that increased happiness would result?
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / e. The One
We can't deduce the phenomena from the One [Armstrong]
     Full Idea: No serious and principled deduction of the phenomena from the One has ever been given, or looks likely to be given.
     From: David M. Armstrong (What is a Law of Nature? [1983], 11)
     A reaction: This seems to pick out the best reason why hardly anybody (apart from Jonathan Schaffer) takes the One seriously.
26. Natural Theory / C. Causation / 2. Types of cause
Absences might be effects, but surely not causes? [Armstrong]
     Full Idea: Lacks and absences could perhaps by thought of as effects, but we ought to be deeply reluctant to think of them as causes.
     From: David M. Armstrong (What is a Law of Nature? [1983], 10.4)
     A reaction: Odd. So we allow that they exist (as effects), but then deny that they have any causal powers?
26. Natural Theory / D. Laws of Nature / 1. Laws of Nature
Science depends on laws of nature to study unobserved times and spaces [Armstrong]
     Full Idea: The scientist trying to establish the geography and history of the unobserved portion of the universe must depend upon what he takes to be the laws of the universe.
     From: David M. Armstrong (What is a Law of Nature? [1983], 01.1)
     A reaction: This does seem to be the prime reason why we wish to invoke 'laws', but we could just as well say that we have to rely on induction. Spot patterns, then expect more of the same. Spot necessities? Mathematics is very valuable here, of course.
A universe couldn't consist of mere laws [Armstrong]
     Full Idea: A universe could hardly consist of laws and nothing else.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.4)
     A reaction: Hm. Discuss. How does a universe come into existence, if there are no laws to guide its creation?
26. Natural Theory / D. Laws of Nature / 2. Types of Laws
Oaken conditional laws, Iron universal laws, and Steel necessary laws [Armstrong, by PG]
     Full Idea: Three degress of law: 1) 'Oaken laws' where all Fs that aren't Hs are Gs; 2) 'Iron' laws where all Fs are Gs; and 3) 'Steel' laws where all Fs must be Gs.
     From: report of David M. Armstrong (What is a Law of Nature? [1983], 10.4) by PG - Db (ideas)
     A reaction: [My summary of Armstrong's distinction] One response is to say that all laws are actually Oaken - see Mumfor and Mumford/Lill Anjum. It's all ceteris paribus.
26. Natural Theory / D. Laws of Nature / 3. Laws and Generalities
Newton's First Law refers to bodies not acted upon by a force, but there may be no such body [Armstrong]
     Full Idea: Newton's First Law of Motion tells us what happens to a body which is not acted upon by a force. Yet it may be that the antecedent of the law is never instantiated. It may be that every body that there is, is acted upon by some force.
     From: David M. Armstrong (What is a Law of Nature? [1983], 02.7)
26. Natural Theory / D. Laws of Nature / 4. Regularities / a. Regularity theory
Regularities are lawful if a second-order universal unites two first-order universals [Armstrong, by Lewis]
     Full Idea: Armstrong's theory holds that what makes certain regularities lawful are second-order states of affairs N(F,G) in which the two ordinary first-order universals F and G are related by a certain dyadic second-order universal N.
     From: report of David M. Armstrong (What is a Law of Nature? [1983]) by David Lewis - New work for a theory of universals 'Laws and C'
     A reaction: [see Lewis's footnote] I take the view (from Shoemaker and Ellis) that laws of nature are just plain regularities which arise from the hierarchy of natural kinds. We don't need a commitment to 'universals'.
A naive regularity view says if it never occurs then it is impossible [Armstrong]
     Full Idea: It is a Humean uniformity that no race of ravens is white-feathered. Hence, if the Naive Regularity analysis of law is correct, it is a law that no race of ravens is white-feathered, that is, such a race is physically impossible. A most unwelcome result.
     From: David M. Armstrong (What is a Law of Nature? [1983], 02.6)
     A reaction: Chapters 2-4 of Armstrong are a storming attack on the regularity view of laws of nature, and this idea is particularly nice. Laws must refer to what could happen, not what happens to happen.
26. Natural Theory / D. Laws of Nature / 5. Laws from Universals
The laws of nature link properties with properties [Armstrong]
     Full Idea: There is an utterly natural idea that the laws of nature link properties with properties.
     From: David M. Armstrong (What is a Law of Nature? [1983], 06.3)
     A reaction: Put it this way: given that properties are expressions of invariant powers, the interaction of two properties will (ceteris paribus) be invariant, and laws are just invariances in natural behaviour.
Rather than take necessitation between universals as primitive, just make laws primitive [Maudlin on Armstrong]
     Full Idea: My own view is simple: the laws of nature ought to be accepted as ontologically primitive. …They are preferable in point of familiarity to such necessitation relations between universals.
     From: comment on David M. Armstrong (What is a Law of Nature? [1983]) by Tim Maudlin - The Metaphysics within Physics 1.4
     A reaction: I think you make natures of things primitive, and reduce laws to regularities and universals to resemblances. Job done. Natures are even more 'familiar' as primitives than laws are.
Armstrong has an unclear notion of contingent necessitation, which can't necessitate anything [Bird on Armstrong]
     Full Idea: The two criticisms levelled against Armstrong are that it is unclear what his relation of contingent necessitation is, and that it is unclear how it is able to necessitate anything.
     From: comment on David M. Armstrong (What is a Law of Nature? [1983]) by Alexander Bird - Nature's Metaphysics 3.1.2
     A reaction: I suppose someone has to explore the middle ground between the mere contingencies of Humean regularities and the strong necessities of scientific essentialism. The area doesn't, however, look promising.