75 ideas
| 13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
| Full Idea: We are all post-Kantians, ...because Kant set an agenda for philosophy that we are still working through. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) | |
| A reaction: Hart says that the main agenda is set by Kant's desire to defend the principle of sufficient reason against Hume's attack on causation. I would take it more generally to be the assessment of metaphysics, and of a priori knowledge. |
| 13477 | The problems are the monuments of philosophy [Hart,WD] |
| Full Idea: The real monuments of philosophy are its problems. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) | |
| A reaction: Presumably he means '....rather than its solutions'. No other subject would be very happy with that sort of claim. Compare Idea 8243. A complaint against analytic philosophy is that it has achieved no consensus at all. |
| 13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
| Full Idea: By now, no education in abstract pursuits is adequate without some familiarity with sets. | |
| From: William D. Hart (The Evolution of Logic [2010], 10) | |
| A reaction: A heart-sinking observation for those who aspire to study metaphysics and modality. The question is, what will count as 'some' familiarity? Are only professional logicians now allowed to be proper philosophers? |
| 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? |
| 13469 | Tarski showed how we could have a correspondence theory of truth, without using 'facts' [Hart,WD] |
| Full Idea: It is an ancient and honourable view that truth is correspondence to fact; Tarski showed us how to do without facts here. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) | |
| A reaction: This is a very interesting spin on Tarski, who certainly seems to endorse the correspondence theory, even while apparently inventing a new 'semantic' theory of truth. It is controversial how far Tarski's theory really is a 'correspondence' theory. |
| 13504 | Truth for sentences is satisfaction of formulae; for sentences, either all sequences satisfy it (true) or none do [Hart,WD] |
| Full Idea: We explain truth for sentences in terms of satisfaction of formulae. The crux here is that for a sentence, either all sequences satisfy it or none do (with no middle ground). For formulae, some sequences may satisfy it and others not. | |
| From: William D. Hart (The Evolution of Logic [2010], 4) | |
| A reaction: This is the hardest part of Tarski's theory of truth to grasp. |
| 13503 | A first-order language has an infinity of T-sentences, which cannot add up to a definition of truth [Hart,WD] |
| Full Idea: In any first-order language, there are infinitely many T-sentences. Since definitions should be finite, the agglomeration of all the T-sentences is not a definition of truth. | |
| From: William D. Hart (The Evolution of Logic [2010], 4) | |
| A reaction: This may be a warning shot aimed at Davidson's extensive use of Tarski's formal account in his own views on meaning in natural language. |
| 13500 | Conditional Proof: infer a conditional, if the consequent can be deduced from the antecedent [Hart,WD] |
| Full Idea: A 'conditional proof' licenses inferences to a conditional from a deduction of its consequent from its antecedent. | |
| From: William D. Hart (The Evolution of Logic [2010], 4) | |
| A reaction: That is, a proof can be enshrined in an arrow. |
| 13502 | ∃y... is read as 'There exists an individual, call it y, such that...', and not 'There exists a y such that...' [Hart,WD] |
| Full Idea: When a quantifier is attached to a variable, as in '∃(y)....', then it should be read as 'There exists an individual, call it y, such that....'. One should not read it as 'There exists a y such that...', which would attach predicate to quantifier. | |
| From: William D. Hart (The Evolution of Logic [2010], 4) | |
| A reaction: The point is to make clear that in classical logic the predicates attach to the objects, and not to some formal component like a quantifier. |
| 13456 | Set theory articulates the concept of order (through relations) [Hart,WD] |
| Full Idea: It is set theory, and more specifically the theory of relations, that articulates order. | |
| From: William D. Hart (The Evolution of Logic [2010]) | |
| A reaction: It would seem that we mainly need set theory in order to talk accurately about order, and about infinity. The two come together in the study of the ordinal numbers. |
| 13497 | Nowadays ZFC and NBG are the set theories; types are dead, and NF is only useful for the whole universe [Hart,WD] |
| Full Idea: The theory of types is a thing of the past. There is now nothing to choose between ZFC and NBG (Neumann-Bernays-Gödel). NF (Quine's) is a more specialized taste, but is a place to look if you want the universe. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) |
| 13443 | ∈ relates across layers, while ⊆ relates within layers [Hart,WD] |
| Full Idea: ∈ relates across layers (Plato is a member of his unit set and the set of people), while ⊆ relates within layers (the singleton of Plato is a subset of the set of people). This distinction only became clear in the 19th century. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) | |
| A reaction: Getting these two clear may be the most important distinction needed to understand how set theory works. |
| 13442 | Without the empty set we could not form a∩b without checking that a and b meet [Hart,WD] |
| Full Idea: Without the empty set, disjoint sets would have no intersection, and we could not form a∩b without checking that a and b meet. This is an example of the utility of the empty set. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) | |
| A reaction: A novice might plausibly ask why there should be an intersection for every pair of sets, if they have nothing in common except for containing this little puff of nothingness. But then what do novices know? |
| 13493 | In the modern view, foundation is the heart of the way to do set theory [Hart,WD] |
| Full Idea: In the second half of the twentieth century there emerged the opinion that foundation is the heart of the way to do set theory. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) | |
| A reaction: It is foundation which is the central axiom of the iterative conception of sets, where each level of sets is built on previous levels, and they are all 'well-founded'. |
| 13495 | Foundation Axiom: an nonempty set has a member disjoint from it [Hart,WD] |
| Full Idea: The usual statement of Foundation is that any nonempty set has a member disjoint from it. This phrasing is ordinal-free and closer to the primitives of ZFC. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) |
| 13461 | We can choose from finite and evident sets, but not from infinite opaque ones [Hart,WD] |
| Full Idea: When a set is finite, we can prove it has a choice function (∀x x∈A → f(x)∈A), but we need an axiom when A is infinite and the members opaque. From infinite shoes we can pick a left one, but from socks we need the axiom of choice. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) | |
| A reaction: The socks example in from Russell 1919:126. |
| 13462 | With the Axiom of Choice every set can be well-ordered [Hart,WD] |
| Full Idea: It follows from the Axiom of Choice that every set can be well-ordered. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) | |
| A reaction: For 'well-ordered' see Idea 13460. Every set can be ordered with a least member. |
| 13516 | If we accept that V=L, it seems to settle all the open questions of set theory [Hart,WD] |
| Full Idea: It has been said (by Burt Dreben) that the only reason set theorists do not generally buy the view that V = L is that it would put them out of business by settling their open questions. | |
| From: William D. Hart (The Evolution of Logic [2010], 10) | |
| A reaction: Hart says V=L breaks with the interative conception of sets at level ω+1, which is countable is the constructible view, but has continuum many in the cumulative (iterative) hierarch. The constructible V=L view is anti-platonist. |
| 13441 | Naïve set theory has trouble with comprehension, the claim that every predicate has an extension [Hart,WD] |
| Full Idea: 'Comprehension' is the assumption that every predicate has an extension. Naïve set theory is the theory whose axioms are extensionality and comprehension, and comprehension is thought to be its naivety. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) | |
| A reaction: This doesn't, of course, mean that there couldn't be a more modest version of comprehension. The notorious difficulty come with the discovery of self-referring predicates which can't possibly have extensions. |
| 13494 | The iterative conception may not be necessary, and may have fixed points or infinitely descending chains [Hart,WD] |
| Full Idea: That the iterative sets suffice for most of ZFC does not show they are necessary, nor is it evident that the set of operations has no fixed points (as 0 is a fixed point for square-of), and no infinitely descending chains (like negative integers). | |
| From: William D. Hart (The Evolution of Logic [2010], 3) | |
| A reaction: People don't seem to worry that they aren't 'necessary', and further measures are possible to block infinitely descending chains. |
| 13457 | A 'partial ordering' is irreflexive and transitive; the sets are ordered, but not the subsets [Hart,WD] |
| Full Idea: We say that a binary relation R 'partially orders' a field A just in case R is irreflexive (so that nothing bears R to itself) and transitive. When the set is {a,b}, its subsets {a} and {b} are incomparable in a partial ordering. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) |
| 13458 | A partial ordering becomes 'total' if any two members of its field are comparable [Hart,WD] |
| Full Idea: A partial ordering is a 'total ordering' just in case any two members of its field are comparable, that is, either a is R to b, or b is R to a, or a is b. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) | |
| A reaction: See Idea 13457 for 'partial ordering'. The three conditions are known as the 'trichotomy' condition. |
| 13460 | 'Well-ordering' must have a least member, so it does the natural numbers but not the integers [Hart,WD] |
| Full Idea: A total order 'well-orders' its field just in case any nonempty subset B of its field has an R-least member, that is, there is a b in B such that for any a in B different from b, b bears R to a. So less-than well-orders natural numbers, but not integers. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) | |
| A reaction: The natural numbers have a starting point, but the integers are infinite in both directions. In plain English, an order is 'well-ordered' if there is a starting point. |
| 13490 | Von Neumann defines α<β as α∈β [Hart,WD] |
| Full Idea: One of the glories of Von Neumann's theory of numbers is to define α < β to mean that α ∈ β. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) |
| 13481 | Maybe sets should be rethought in terms of the even more basic categories [Hart,WD] |
| Full Idea: Some have claimed that sets should be rethought in terms of still more basic things, categories. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) | |
| A reaction: [He cites F.William Lawvere 1966] It appears to the the context of foundations for mathematics that he has in mind. |
| 13506 | The universal quantifier can't really mean 'all', because there is no universal set [Hart,WD] |
| Full Idea: All the main set theories deny that there is a set of which everything is a member. No interpretation has a domain with everything in it. So the universal quantifier never gets to mean everything all at once; 'all' does not mean all. | |
| From: William D. Hart (The Evolution of Logic [2010], 4) | |
| A reaction: Could you have an 'uncompleted' universal set, in the spirit of uncompleted infinities? In ordinary English we can talk about 'absolutely everything' - we just can't define a set of everything. Must we 'define' our domain? |
| 13512 | Modern model theory begins with the proof of Los's Conjecture in 1962 [Hart,WD] |
| Full Idea: The beginning of modern model theory was when Morley proved Los's Conjecture in 1962 - that a complete theory in a countable language categorical in one uncountable cardinal is categorical in all. | |
| From: William D. Hart (The Evolution of Logic [2010], 9) |
| 13505 | Model theory studies how set theory can model sets of sentences [Hart,WD] |
| Full Idea: Modern model theory investigates which set theoretic structures are models for which collections of sentences. | |
| From: William D. Hart (The Evolution of Logic [2010], 4) | |
| A reaction: So first you must choose your set theory (see Idea 13497). Then you presumably look at how to formalise sentences, and then look at the really tricky ones, many of which will involve various degrees of infinity. |
| 13511 | Model theory is mostly confined to first-order theories [Hart,WD] |
| Full Idea: There is no developed methematics of models for second-order theories, so for the most part, model theory is about models for first-order theories. | |
| From: William D. Hart (The Evolution of Logic [2010], 9) |
| 13513 | Models are ways the world might be from a first-order point of view [Hart,WD] |
| Full Idea: Models are ways the world might be from a first-order point of view. | |
| From: William D. Hart (The Evolution of Logic [2010], 9) |
| 13496 | First-order logic is 'compact': consequences of a set are consequences of a finite subset [Hart,WD] |
| Full Idea: First-order logic is 'compact', which means that any logical consequence of a set (finite or infinite) of first-order sentences is a logical consequence of a finite subset of those sentences. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) |
| 13484 | Berry's Paradox: we succeed in referring to a number, with a term which says we can't do that [Hart,WD] |
| Full Idea: Berry's Paradox: by the least number principle 'the least number denoted by no description of fewer than 79 letters' exists, but we just referred to it using a description of 77 letters. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) | |
| A reaction: I struggle with this. If I refer to 'an object to which no human being could possibly refer', have I just referred to something? Graham Priest likes this sort of idea. |
| 13482 | The Burali-Forti paradox is a crisis for Cantor's ordinals [Hart,WD] |
| Full Idea: The Burali-Forti Paradox was a crisis for Cantor's theory of ordinal numbers. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) |
| 13507 | The machinery used to solve the Liar can be rejigged to produce a new Liar [Hart,WD] |
| Full Idea: In effect, the machinery introduced to solve the liar can always be rejigged to yield another version the liar. | |
| From: William D. Hart (The Evolution of Logic [2010], 4) | |
| A reaction: [He cites Hans Herzberger 1980-81] The machinery is Tarski's device of only talking about sentences of a language by using a 'metalanguage'. |
| 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. |
| 13459 | The less-than relation < well-orders, and partially orders, and totally orders the ordinal numbers [Hart,WD] |
| Full Idea: We can show (using the axiom of choice) that the less-than relation, <, well-orders the ordinals, ...and that it partially orders the ordinals, ...and that it totally orders the ordinals. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) |
| 13491 | The axiom of infinity with separation gives a least limit ordinal ω [Hart,WD] |
| Full Idea: The axiom of infinity with separation yields a least limit ordinal, which is called ω. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) |
| 13463 | There are at least as many infinite cardinals as transfinite ordinals (because they will map) [Hart,WD] |
| Full Idea: Since we can map the transfinite ordinals one-one into the infinite cardinals, there are at least as many infinite cardinals as transfinite ordinals. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) |
| 13492 | Von Neumann's ordinals generalise into the transfinite better, because Zermelo's ω is a singleton [Hart,WD] |
| Full Idea: It is easier to generalize von Neumann's finite ordinals into the transfinite. All Zermelo's nonzero finite ordinals are singletons, but if ω were a singleton it is hard to see how if could fail to be the successor of its member and so not a limit. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) |
| 13446 | 19th century arithmetization of analysis isolated the real numbers from geometry [Hart,WD] |
| Full Idea: The real numbers were not isolated from geometry until the arithmetization of analysis during the nineteenth century. | |
| From: William D. Hart (The Evolution of Logic [2010], 1) |
| 13509 | We can establish truths about infinite numbers by means of induction [Hart,WD] |
| Full Idea: Mathematical induction is a way to establish truths about the infinity of natural numbers by a finite proof. | |
| From: William D. Hart (The Evolution of Logic [2010], 5) | |
| A reaction: If there are truths about infinities, it is very tempting to infer that the infinities must therefore 'exist'. A nice, and large, question in philosophy is whether there can be truths without corresponding implications of existence. |
| 13474 | Euclid has a unique parallel, spherical geometry has none, and saddle geometry has several [Hart,WD] |
| Full Idea: There is a familiar comparison between Euclid (unique parallel) and 'spherical' geometry (no parallel) and 'saddle' geometry (several parallels). | |
| From: William D. Hart (The Evolution of Logic [2010], 2) |
| 13471 | Mathematics makes existence claims, but philosophers usually say those are never analytic [Hart,WD] |
| Full Idea: The thesis that no existence proposition is analytic is one of the few constants in philosophical consciences, but there are many existence claims in mathematics, such as the infinity of primes, five regular solids, and certain undecidable propositions. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) |
| 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. |
| 13488 | Mass words do not have plurals, or numerical adjectives, or use 'fewer' [Hart,WD] |
| Full Idea: Jespersen calls a noun a mass word when it has no plural, does not take numerical adjectives, and does not take 'fewer'. | |
| From: William D. Hart (The Evolution of Logic [2010], 3) | |
| A reaction: Jespersen was a great linguistics expert. |
| 12253 | If tropes are in space and time, in what sense are they abstract? [Oderberg] |
| Full Idea: If tropes are in space and time, in what sense are they abstract? | |
| From: David S. Oderberg (Real Essentialism [2007], 4.5) | |
| A reaction: I take this to be a conclusive objection to claims for any such thing to be abstract. See, for example, Dummett's claim that the Equator is an abstract object. |
| 12256 | We need to distinguish the essential from the non-essential powers [Oderberg] |
| Full Idea: We need a theory of essence to help us distinguish between the powers that do and do not belong to the essence of a thing. | |
| From: David S. Oderberg (Real Essentialism [2007], 6.3) | |
| A reaction: I take this to be a very good reason for searching for the essence of things, though the need to distinguish does not guarantee that there really is something to distinguish. Maybe powers just come and go. A power is essential in you but not in me? |
| 12252 | Empiricists gave up 'substance', as unknowable substratum, or reducible to a bundle [Oderberg] |
| Full Idea: The demise of 'substance' was wholly due to mistaken notions, mainly from the empiricists, by which it was conceived either as an unknowable featureless substratum, or as dispensable in favour of some or other bundle theory. | |
| From: David S. Oderberg (Real Essentialism [2007], 4.4) | |
| A reaction: There seems to be a view that the notion of substance is essential to explaining how we understand the world. I am inclined to think that if we accept the notion of essence we can totally dispense with the notion of substance. |
| 12241 | Essences are real, about being, knowable, definable and classifiable [Oderberg, by PG] |
| Full Idea: Real essences are objectively real, they concern being, they are knowable, they are definable, and they are classifiable. | |
| From: report of David S. Oderberg (Real Essentialism [2007], 1.4) by PG - Db (ideas) | |
| A reaction: This is a lovely summary (spread over two pages) of what essentialism is all about. It might be added that they are about unity and identity. The fact that they are intrinsically classifiable seems to mislead some people into a confused view. |
| 12244 | Nominalism is consistent with individual but not with universal essences [Oderberg] |
| Full Idea: Nominalism is consistent with belief in individual essences, but real essentialism postulates essences as universals (quiddities). Nominalists are nearly always empiricists, though the converse may not be the case. | |
| From: David S. Oderberg (Real Essentialism [2007], 2.1) | |
| A reaction: This is where I part company with Oderberg. I want to argue that the nominalist/individualist view is more in tune with what Aristotle believed (though he spotted a dilemma here). Only individual essences explain individual behaviour. |
| 12240 | Essentialism is the main account of the unity of objects [Oderberg] |
| Full Idea: Real essentialism, more than any other ontological theory, stresses and seeks to explain the unity of objects. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.3) | |
| A reaction: A key piece in the jigsaw I am beginning to assemble. If explanation is the aim, and essence the key to explanation, then explaining unity is the part of it that connects with other metaphysics, about identity and so on. 'Units' breed numbers. |
| 12247 | Essence is not explanatory but constitutive [Oderberg] |
| Full Idea: Essence is not reducible to explanatory relations, ...and fundamentally the role of essence is not explanatory but constitutive. | |
| From: David S. Oderberg (Real Essentialism [2007], 3.1) | |
| A reaction: Effectively, this asserts essence as part of 'pure' metaphysics, but I like impure metaphysics, as the best explanation of the things we can know. Hence we can speculate about constitution only by means of explanation. Constitution is active. |
| 12258 | Properties are not part of an essence, but they flow from it [Oderberg] |
| Full Idea: A substance is constituted by its essence, and properties are a species of accident. No property of a thing is part of a thing's essence, though properties flow from the essence. | |
| From: David S. Oderberg (Real Essentialism [2007], 7.2) | |
| A reaction: I'm not sure I understand this. How can you know of something which has no properties? I'm wondering if the whole notion of a 'property' should be eliminated from good metaphysics. |
| 12257 | Could we replace essence with collections of powers? [Oderberg] |
| Full Idea: Why not do away with talk of essences and replace it with talk of powers pure and simple, or reduce essences to collections of powers? But then what unites the powers, and could a power be lost, and is there entailment between the powers? | |
| From: David S. Oderberg (Real Essentialism [2007], 6.3) | |
| A reaction: [He cites Bennett and Hacker 2003 for this view] The point would seem to be that in addition to the powers, there are also identity and unity and kind-membership to be explained. Oderberg says the powers flow from the essence. |
| 12236 | Leibniz's Law is an essentialist truth [Oderberg] |
| Full Idea: Leibniz's Law is an essentialist truth. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: That is, if two things must have identical properties because they are the same thing, this is because those properties are essential to the thing. Otherwise two things could be the same, even though one of them lacked a non-identifying property. |
| 12250 | Bodies have act and potency, the latter explaining new kinds of existence [Oderberg] |
| Full Idea: The fundamental thesis of real essentialism is that every finite material body has a twofold composition, being a compound of act and potency. ...Reality can take on new kinds of existence because there is a principle of potentiality inherent in reality. | |
| From: David S. Oderberg (Real Essentialism [2007], 4.1) | |
| A reaction: I take from this remark that the 'powers' discussed by Molnar and other scientific essentialists is roughly the same as 'potentiality' identified by Aristotle. |
| 12234 | Realism about possible worlds is circular, since it needs a criterion of 'possible' [Oderberg] |
| Full Idea: Any realist theory of possible worlds will be circular in its attempt to illuminate modality, for there has to be some criterion of what counts as a possible world. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: Seems right. At the very least, if we are going to rule out contradictory worlds as impossible (and is there a more obvious criterion?), we already need to understand 'impossible' in order to state that rule. |
| 12235 | Necessity of identity seems trivial, because it leaves out the real essence [Oderberg] |
| Full Idea: The necessity of identity carries the appearance of triviality, because it is the eviscerated contemporary essentialist form of a foundational real essentialist truth to the effect that every object has its own nature. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: I like this. Writers like Mackie and Forbes have to put the 'trivial' aspects of essence to one side, without ever seeing why there is such a problem. Real substantial essences have necessity of identity as a side-effect. |
| 12237 | Rigid designation has at least three essentialist presuppositions [Oderberg] |
| Full Idea: The rigid designator approach to essentialism has essentialist assumptions. ..The necessity of identity is built into the very conception of a rigid designator,..and Leibniz's Law is presupposed...and necessity of origin presupposes sufficiency of origin. | |
| From: David S. Oderberg (Real Essentialism [2007], 1.1) | |
| A reaction: [compressed. He cites Salmon 1981:196 for the last point] This sounds right. You feel happy to 'rigidly designate' something precisely because you think there is something definite and stable which can be designated. |
| 7630 | Ryle's dichotomy between knowing how and knowing that is too simplistic [Maund] |
| Full Idea: There is a convincing claim that we need to leave behind Ryle's dichotomy between knowing how and knowing that as being too simplistic. | |
| From: Barry Maund (Perception [2003], Ch. 2) | |
| A reaction: [John Campbell is mentioned as source of this idea] I find this proposal immediately appealing. I was taught that riding a bicycle shows the division, as hardly anyone knows the theory, but I am sure children need some propositional information. |
| 13480 | Fregean self-evidence is an intrinsic property of basic truths, rules and definitions [Hart,WD] |
| Full Idea: The conception of Frege is that self-evidence is an intrinsic property of the basic truths, rules, and thoughts expressed by definitions. | |
| From: William D. Hart (The Evolution of Logic [2010], p.350) | |
| A reaction: The problem is always that what appears to be self-evident may turn out to be wrong. Presumably the effort of arriving at a definition ought to clarify and support the self-evident ingredient. |
| 13476 | The failure of key assumptions in geometry, mereology and set theory throw doubt on the a priori [Hart,WD] |
| Full Idea: In the case of the parallels postulate, Euclid's fifth axiom (the whole is greater than the part), and comprehension, saying was believing for a while, but what was said was false. This should make a shrewd philosopher sceptical about a priori knowledge. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) | |
| A reaction: Euclid's fifth is challenged by infinite numbers, and comprehension is challenged by Russell's paradox. I can't see a defender of the a priori being greatly worried about these cases. No one ever said we would be right - in doing arithmetic, for example. |
| 7632 | Perception is sensation-then-concept, or direct-concepts, or sensation-saturated-in-concepts [Maund] |
| Full Idea: Three forms of (cognitive) direct realism are: two stages - non-conceptual sensory experience, then a non-sensory conceptual state; directly acquiring non-sensuous conceptual states; and sensuous states saturated with concepts. | |
| From: Barry Maund (Perception [2003], Ch. 3) | |
| A reaction: [First: Reid, Dretske, Evans, Sellars. Second: Armstrong, Heil, Pitcher, Clark. Third: Kant, McDowell, Strawson, McGinn, Searle]. I find the first one plausible, because of the ambiguity in language, and because unusual experiences separate them. |
| 7635 | Sense-data have an epistemological purpose (foundations) and a metaphysical purpose (explanation) [Maund] |
| Full Idea: Sense-data have an epistemological purpose (to serve as foundations on which the edifice of knowledge is to be constructed), and a metaphysical purpose (to provide an accurate account of the phenomenology of perceptual experience). | |
| From: Barry Maund (Perception [2003], Ch. 6) | |
| A reaction: This is very important, because there is a real danger (e.g. in Russell) that the epistemological convenience of sense-data for giving reliability in knowledge means that we are too quick in making the assumption that they actually exist. |
| 7638 | One thesis says we are not aware of qualia, but only of objects and their qualities [Maund] |
| Full Idea: The representationalist/intentionalist thesis about perception is that we are not aware of the intrinsic qualities of experience in normal perception; we are instead aware of those objects and their qualities that are specified in the content. | |
| From: Barry Maund (Perception [2003], Ch. 9) | |
| A reaction: If secondary qualities are in the mind, not in objects, how come people always thought they were in objects? Answer: because this thesis is right? The primary mode of the mind is projected outwards, though we can introspect about colours. [Dretske] |
| 7642 | The Myth of the Given claims that thought is rationally supported by non-conceptual experiences [Maund] |
| Full Idea: The so-called 'myth of the given' is the view that conceptual content can be rationally supported by experiences construed as states with non-conceptual content. | |
| From: Barry Maund (Perception [2003], Ch.10) | |
| A reaction: The myth is attacked by Sellars and McDowell, the latter claiming that concepts must be embedded in the experiences. Maybe only realism is required to make the Given work. The experiences are definitely of something, and off we go... |
| 7640 | Mountains are adverbial modifications of the earth, but still have object-characteristics [Maund] |
| Full Idea: Metaphysically, mountains are only adverbial modifications of the Earth's belt. They have no existence independent of being part of the earth. Yet for all that, they have some rather strong 'object'-characteristics. | |
| From: Barry Maund (Perception [2003], Ch.10) | |
| A reaction: The point being that you don't give up all the advantages of a sense-data view if you switch to adverbialism. I'm not convinced by the analogy, but we can only be aware of adverbial qualities if they have causal powers. |
| 7641 | Adverbialism tries to avoid sense-data and preserve direct realism [Maund] |
| Full Idea: The two primary motivations of the adverbialist analysis are thought to be to avoid commitment to sensory particulars such as sense-data, and to allow us to hold on to a version of direct realism. | |
| From: Barry Maund (Perception [2003], Ch.10) | |
| A reaction: Maund says that the adverbialist's fears about indirect/representative theories are unfounded. My feeling is that neither account will do the job properly once we get a better account of consciousness. Maybe adverbialism is only for secondary qualities. |
| 7637 | Thought content is either satisfaction conditions, or exercise of concepts [Maund, by PG] |
| Full Idea: The content of thought can either be expressed as satisfaction conditions (e.g. truth-conditions for beliefs), or as the exercise of at least two concepts. | |
| From: report of Barry Maund (Perception [2003], Ch. 8) by PG - Db (ideas) | |
| A reaction: I think I favour the first view, because not all conjunctions of concepts would count as thoughts (e.g. rhubarb-plus-contradiction). A bunch of concepts becomes a thought when it connects in some way to reality? |
| 13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
| Full Idea: A Fregean concept is a function that assigns to each object a truth value. So instead of the colour green, the concept GREEN assigns truth to each green thing, but falsity to anything else. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) | |
| A reaction: This would seem to immediately hit the renate/cordate problem, if there was a world in which all and only the green things happened to be square. How could Frege then distinguish the green from the square? Compare Idea 8245. |
| 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. |