44 ideas
| 9550 | We only know relational facts about the empty set, but nothing intrinsic [Chihara] |
| Full Idea: Everything we know about the empty set is relational; we know that nothing is the membership relation to it. But what do we know about its 'intrinsic properties'? | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 01.5) | |
| A reaction: Set theory seems to depend on the concept of the empty set. Modern theorists seem over-influenced by the Quine-Putnam view, that if science needs it, we must commit ourselves to its existence. |
| 9562 | In simple type theory there is a hierarchy of null sets [Chihara] |
| Full Idea: In simple type theory, there is a null set of type 1, a null set of type 2, a null set of type 3..... (Quine has expressed his distaste for this). | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 07.4) | |
| A reaction: It is bad enough trying to individuate the unique null set, without whole gangs of them drifting indistinguishably through the logical fog. All rational beings should share Quine's distaste, even if Quine is wrong. |
| 9572 | Realists about sets say there exists a null set in the real world, with no members [Chihara] |
| Full Idea: In the Gödelian realistic view of set theory the statement that there is a null set as the assertion of the existence in the real world of a set that has no members. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 11.6) | |
| A reaction: It seems to me obvious that such a claim is nonsense on stilts. 'In the beginning there was the null set'? |
| 9573 | The null set is a structural position which has no other position in membership relation [Chihara] |
| Full Idea: In the structuralist view of sets, in structures of a certain sort the null set is taken to be a position (or point) that will be such that no other position (or point) will be in the membership relation to it. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 11.6) | |
| A reaction: It would be hard to conceive of something having a place in a structure if nothing had a relation to it, so is the null set related to singeton sets but not there members. It will be hard to avoid Platonism here. Set theory needs the null set. |
| 9551 | What is special about Bill Clinton's unit set, in comparison with all the others? [Chihara] |
| Full Idea: What is it about the intrinsic properties of just that one unit set in virtue of which Bill Clinton is related to just it and not to any other unit sets in the set-theoretical universe? | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 01.5) | |
| A reaction: If we all kept pet woodlice, we had better not hold a wood louse rally, or we might go home with the wrong one. My singleton seems seems remarkably like yours. Could we, perhaps, swap, just for a change? |
| 9549 | The set theorist cannot tell us what 'membership' is [Chihara] |
| Full Idea: The set theorist cannot tell us anything about the true relationship of membership. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 01.5) | |
| A reaction: If three unrelated objects suddenly became members of a set, it is hard to see how the world would have changed, except in the minds of those thinking about it. |
| 9571 | ZFU refers to the physical world, when it talks of 'urelements' [Chihara] |
| Full Idea: ZFU set theory talks about physical objects (the urelements), and hence is in some way about the physical world. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 11.5) | |
| A reaction: This sounds a bit surprising, given that the whole theory would appear to be quite unaffected if God announced that idealism is true and there are no physical objects. |
| 18151 | Could we replace sets by the open sentences that define them? [Chihara, by Bostock] |
| Full Idea: Chihara proposes to replace all sets by reference to the open sentences that define them. | |
| From: report of Charles Chihara (Ontology and the Vicious Circle Principle [1973]) by David Bostock - Philosophy of Mathematics 9.B.4 | |
| A reaction: This depends on predicativism, because that stipulates the definitions will be available (cos if it ain't definable it ain't there). Chihara went on to define the open sentences in terms of the possibility of uttering them. Cf. propositional functions. |
| 8758 | We could talk of open sentences, instead of sets [Chihara, by Shapiro] |
| Full Idea: Chihara's programme is to replace talk of sets with talk of open sentences. Instead of speaking of the set of all cats, we talk about the open sentence 'x is a cat'. | |
| From: report of Charles Chihara (Constructibility and Mathematical Existence [1990]) by Stewart Shapiro - Thinking About Mathematics 9.2 | |
| A reaction: As Shapiro points out, this is following up Russell's view that sets should be replaced with talk of properties. Chihara is expressing it more linguistically. I'm in favour of any attempt to get rid of sets. |
| 9563 | A pack of wolves doesn't cease when one member dies [Chihara] |
| Full Idea: A pack of wolves is not thought to go out of existence just because some member of the pack is killed. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 07.5) | |
| A reaction: The point is that the formal extensional notion of a set doesn't correspond to our common sense notion of a group or class. Even a highly scientific theory about wolves needs a loose notion of a wolf pack. |
| 9561 | The mathematics of relations is entirely covered by ordered pairs [Chihara] |
| Full Idea: Everything one needs to do with relations in mathematics can be done by taking a relation to be a set of ordered pairs. (Ordered triples etc. can be defined as order pairs, so that <x,y,z> is <x,<y,z>>). | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 07.2) | |
| A reaction: How do we distinguish 'I own my cat' from 'I love my cat'? Or 'I quite like my cat' from 'I adore my cat'? Nevertheless, this is an interesting starting point for a discussion of relations. |
| 9552 | Sentences are consistent if they can all be true; for Frege it is that no contradiction can be deduced [Chihara] |
| Full Idea: In first-order logic a set of sentences is 'consistent' iff there is an interpretation (or structure) in which the set of sentences is true. ..For Frege, though, a set of sentences is consistent if it is not possible to deduce a contradiction from it. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 02.1) | |
| A reaction: The first approach seems positive, the second negative. Frege seems to have a higher standard, which is appealing, but the first one seems intuitively right. There is a possible world where this could work. |
| 9553 | Analytic geometry gave space a mathematical structure, which could then have axioms [Chihara] |
| Full Idea: With the invention of analytic geometry (by Fermat and then Descartes) physical space could be represented as having a mathematical structure, which could eventually lead to its axiomatization (by Hilbert). | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 02.3) | |
| A reaction: The idea that space might have axioms seems to be pythagoreanism run riot. I wonder if there is some flaw at the heart of Einstein's General Theory because of this? |
| 10192 | We can replace existence of sets with possibility of constructing token sentences [Chihara, by MacBride] |
| Full Idea: Chihara's 'constructability theory' is nominalist - mathematics is reducible to a simple theory of types. Instead of talk of sets {x:x is F}, we talk of open sentences Fx defining them. Existence claims become constructability of sentence tokens. | |
| From: report of Charles Chihara (A Structural Account of Mathematics [2004]) by Fraser MacBride - Review of Chihara's 'Structural Acc of Maths' p.81 | |
| A reaction: This seems to be approaching the problem in a Fregean way, by giving an account of the semantics. Chihara is trying to evade the Quinean idea that assertion is ontological commitment. But has Chihara retreated too far? How does he assert existence? |
| 10265 | Chihara's system is a variant of type theory, from which he can translate sentences [Chihara, by Shapiro] |
| Full Idea: Chihara's system is a version of type theory. Translate thus: replace variables of sets of type n with level n variables over open sentences, replace membership/predication with satisfaction, and high quantifiers with constructability quantifiers. | |
| From: report of Charles Chihara (Constructibility and Mathematical Existence [1990]) by Stewart Shapiro - Philosophy of Mathematics 7.4 |
| 8759 | We can replace type theory with open sentences and a constructibility quantifier [Chihara, by Shapiro] |
| Full Idea: Chihara's system is similar to simple type theory; he replaces each type with variables over open sentences, replaces membership (or predication) with satisfaction, and replaces quantifiers over level 1+ variables with constructability quantifiers. | |
| From: report of Charles Chihara (Constructibility and Mathematical Existence [1990]) by Stewart Shapiro - Thinking About Mathematics 9.2 | |
| A reaction: This is interesting for showing that type theory may not be dead. The revival of supposedly dead theories is the bread-and-butter of modern philosophy. |
| 10264 | Introduce a constructibility quantifiers (Cx)Φ - 'it is possible to construct an x such that Φ' [Chihara, by Shapiro] |
| Full Idea: Chihara has proposal a modal primitive, a 'constructability quantifier'. Syntactically it behaves like an ordinary quantifier: Φ is a formula, and x a variable. Then (Cx)Φ is a formula, read as 'it is possible to construct an x such that Φ'. | |
| From: report of Charles Chihara (Constructibility and Mathematical Existence [1990]) by Stewart Shapiro - Philosophy of Mathematics 7.4 | |
| A reaction: We only think natural numbers are infinite because we see no barrier to continuing to count, i.e. to construct new numbers. We accept reals when we know how to construct them. Etc. Sounds promising to me (though not to Shapiro). |
| 9559 | If a successful theory confirms mathematics, presumably a failed theory disconfirms it? [Chihara] |
| Full Idea: If mathematics shares whatever confirmation accrues to the theories using it, would it not be reasonable to suppose that mathematics shares whatever disconfirmation accrues to the theories using it? | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 05.8) | |
| A reaction: Presumably Quine would bite the bullet here, although maths is much closer to the centre of his web of belief, and so far less likely to require adjustment. In practice, though, mathematics is not challenged whenever an experiment fails. |
| 9566 | No scientific explanation would collapse if mathematical objects were shown not to exist [Chihara] |
| Full Idea: Evidently, no scientific explanations of specific phenomena would collapse as a result of any hypothetical discovery that no mathematical objects exist. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 09.1) | |
| A reaction: It is inconceivable that anyone would challenge this claim. A good model seems to be drama; a play needs commitment from actors and audience, even when we know it is fiction. The point is that mathematics doesn't collapse either. |
| 4938 | Prior to language, concepts are universals created by self-mapping of brain activity [Edelman/Tononi] |
| Full Idea: Before language is present, concepts depend on the brain's ability to construct 'universals' through higher-order mapping of the activity of the brain's own perceptual and motor maps. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.15) | |
| A reaction: It should be of great interest to philosophers that one can begin to give a neuro-physiological account of universals. A physical system can be ordered as a database, and universals are the higher branches of a tree-structure of information. |
| 4934 | Cultures have a common core of colour naming, based on three axes of colour pairs [Edelman/Tononi] |
| Full Idea: We seem to have a set of colour axes (red-green, blue-yellow, and light-dark). Color naming in different cultures tend to have universal categories based on these axes, with a few derived or composite categories (e.g. orange, purple, pink, brown, grey). | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.13) | |
| A reaction: This confirms my view of all supposed relativism: that there are degrees of cultural and individual relativism possible, but it is daft to think this goes all the way down, as nature has 'joints', and our minds are part of nature. |
| 4924 | A conscious human being rapidly reunifies its mind after any damage to the brain [Edelman/Tononi] |
| Full Idea: It seems that after a massive stroke or surgical resection, a conscious human being is rapidly "resynthesised" or reunified within the limits of a solipsistic universe that, to outside appearances, is warped and restricted. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch. 3) | |
| A reaction: Note that there are two types of 'unity of mind'. This comment refers to the unity of seeing oneself as a single person, rather than the smooth unbroken quality of conscious experience. I presume that there is no point in a mind without the first unity. |
| 4932 | A conscious state endures for about 100 milliseconds, known as the 'specious present' [Edelman/Tononi] |
| Full Idea: The 'specious present' (William James), a rough estimate of the duration of a single conscious state, is of the order of 100 milliseconds, meaning that conscious states can change very rapidly. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.12) | |
| A reaction: A vital feature of our subjective experience of time. I wonder what the figure is for a fly? It suggests that conscious experience really is like a movie film, composed of tiny independent 'frames' of very short duration. |
| 4931 | Consciousness is a process (of neural interactions), not a location, thing, property, connectivity, or activity [Edelman/Tononi] |
| Full Idea: Consciousness is neither a thing, nor a simple property. ..The conscious 'dynamic core' of the brain is a process, not a thing or a place, and is defined in terms of neural interactions, not in terms of neural locations, connectivity or activity. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.12) | |
| A reaction: This must be of great interest to philosophers. Edelman is adamant that it is not any specific neurons. The nice question is: what would it be like to have your brain slowed down? Presumably we would experience steps in the process. Is he a functionalist? |
| 4923 | The three essentials of conscious experience are privateness, unity and informativeness [Edelman/Tononi] |
| Full Idea: The fundamental aspects of conscious experience that are common to all its phenomenological manifestations are: privateness, unity, and informativeness. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch. 3) | |
| A reaction: Interesting, coming from neuroscientists. The list strikes me as rather passive. It is no use having good radar if you can't make decisions. Privacy and unity are overrated. Who gets 'informed'? Personal identity must be basic. |
| 4941 | Consciousness can create new axioms, but computers can't do that [Edelman/Tononi] |
| Full Idea: Conscious human thought can create new axioms, which a computer cannot do. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.17) | |
| A reaction: A nice challenge for the artificial intelligence community! I don't understand their confidence in making this assertion. Nothing in Gödel's Theorem seems to prevent the reassignment of axioms, and Quine implies that it is an easy and trivial game. |
| 4930 | Consciousness arises from high speed interactions between clusters of neurons [Edelman/Tononi] |
| Full Idea: Our hypothesis is that the activity of a group of neurons can contribute directly to conscious experience if it is part of a functional cluster, characterized by strong interactions among a set of neuronal groups over a period of hundreds of milliseconds. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.12) | |
| A reaction: This is their 'dynamic core' hypothesis. It doesn't get at the Hard Questions about consciousness, but this is a Nobel prize winner hot on the trail of the location of the action. It gives support to functionalism, because the neurons vary. |
| 4929 | Dreams and imagery show the brain can generate awareness and meaning without input [Edelman/Tononi] |
| Full Idea: Dreaming and imagery are striking phenomenological demonstrations that the adult brain can spontaneously and intrinsically produce consciousness and meaning without any direct input from the periphery. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.11) | |
| A reaction: This offers some support for Searle's claim that brain's produce 'intrinsic' (rather than 'derived') intentionality. Of course, one can have a Humean impressions/ideas theory about how the raw material got there. We SEE meaning in our experiences. |
| 4940 | Physicists see information as a measure of order, but for biologists it is symbolic exchange between animals [Edelman/Tononi] |
| Full Idea: Physicists may define information as a measure of order in a far-from-equilibrium state, but it is best seen as a biological concept which emerged in evolution with animals that were capable of mutual symbolic exchange. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.17) | |
| A reaction: The physicists' definition seems to open the road to the possibility of non-conscious intentionality (Dennett), where the biological view seems to require consciousness of symbolic meanings (Searle). Tree-rings contain potential information? |
| 4935 | The sensation of red is a point in neural space created by dimensions of neuronal activity [Edelman/Tononi] |
| Full Idea: The pure sensation of red is a particular neural state identified by a point within the N-dimensional neural space defined by the integrated activity of all the group of neurons that constitute the dynamic core. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.13) | |
| A reaction: This hardly answers the Hard Question (why experience it? why that experience?), but it is interesting to see a neuroscientist fishing for an account of qualia. He says three types of neuron firing generate the dimensions of the 'space'. |
| 4936 | The self is founded on bodily awareness centred in the brain stem [Edelman/Tononi] |
| Full Idea: Structures in the brain stem map the state of the body and its relation to the environment, on the basis of signals with proprioceptive, kinesthetic, somatosensory and autonomic components. We may call these the dimensions of the proto-self. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.13) | |
| A reaction: It seems to me that there is no free will, but moral responsibility depends on the existence of a Self, and philosophers had better fight for it (are you listening, Hume?). Fortunately neuroscientists seem to endorse it fairly unanimously. |
| 4939 | A sense of self begins either internally, or externally through language and society [Edelman/Tononi] |
| Full Idea: Two extreme views on the development of the self are 'internalist' and 'externalist'. The first starts with a baby's subjective experience, and increasing differentiation as self-consciousness develops. The externalist view requires language and society. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.15) | |
| A reaction: Edelman rightly warns against this simple dichotomy, but if I have to vote, it is for internalism. I take a sense of self as basic to any mind, even a slug's. What is a mind for, if not to look after the creature? Self makes sensation into mind. |
| 4925 | Brains can initiate free actions before the person is aware of their own decision [Edelman/Tononi] |
| Full Idea: Libet concluded that the cerebral initiation of a spontaneous, freely voluntary act can begin unconsciously, that is, before there is any recallable awareness that a decision to act has already been initiated cerebrally. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch. 6) | |
| A reaction: We should accept this result. 'Free will' was always a bogus metaphysical concept (invented, I think, because God had to be above natural laws). A person is the source of responsibility, and is the controller of the brain, but not entirely conscious. |
| 4933 | Consciousness is a process, not a thing, as it maintains unity as its composition changes [Edelman/Tononi] |
| Full Idea: The conscious 'dynamic core' of the brain can maintain its unity over time even if its composition may be constantly changing, which is the signature of a process as opposed to a thing. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.12) | |
| A reaction: This is the functionalists' claim that the mind is 'multiply realisable', since different neurons can maintain the same process. 'Process' strikes me as a much better word than 'function'. These theories capture passive mental life better than active. |
| 4928 | Brain complexity balances segregation and integration, like a good team of specialists [Edelman/Tononi] |
| Full Idea: A theoretical analysis of complexity suggests that neuronal complexity strikes an optimum balance between segregation and integration, which fits the view of the brain as a collection of specialists who talk to each other a lot. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.11) | |
| A reaction: This is a theoretical point, but comes from a leading neuroscientist, and seems to endorse Fodor's modularity proposal. For a philosopher, one of the issues here is how to reconcile the segregation with the Cartesian unity and personal identity of a mind. |
| 4927 | Information-processing views of the brain assume the existence of 'information', and dubious brain codes [Edelman/Tononi] |
| Full Idea: So-called information-processing views of the brain have been criticized because they typically assume the existence in the world of previously defined information, and often assume the existence of precise neural codes for which there is no evidence. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.11) | |
| A reaction: Fodor is the target here. Searle is keen that 'intrinsic intentionality' is required to see something as 'information'. It is hard to see how anything acquires significance as it flows through a mechanical process. |
| 4922 | Consciousness involves interaction with persons and the world, as well as brain functions [Edelman/Tononi] |
| Full Idea: We emphatically do not identify consciousness in its full range as arising solely in the brain, since we believe that higher brain functions require interactions both with the world and with other persons. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Pref) | |
| A reaction: Would you gradually lose higher brain functions if you lived entirely alone? Intriguingly, this sounds like a neuroscientist asserting the necessity for broad content in order to understand the brain. |
| 5793 | Concepts and generalisations result from brain 'global mapping' by 'reentry' [Edelman/Tononi, by Searle] |
| Full Idea: When you get maps all over the brain signalling to each other by reentry you have what Edelman calls 'global mapping', and this allows the system not only to have perceptual categories and generalisation, but also to coordinate perception and action. | |
| From: report of G Edelman / G Tononi (Consciousness: matter becomes imagination [2000]) by John Searle - The Mystery of Consciousness Ch.3 | |
| A reaction: This is the nearest we have got to a proper scientific account of thought (as opposed to untested speculation about Turing machines). Something like this account must be right. A concept is a sustained process, not a static item. |
| 4926 | Concepts arise when the brain maps its own activities [Edelman/Tononi] |
| Full Idea: We propose that concepts arise from the mapping by the brain itself of the activity of the brain's own areas and regions. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch. 9) | |
| A reaction: Yes. One should add that the brain appears to be physically constructed with the logic of a filing system, which would mean that our concepts were labels for files within the system. Nature generates some of the files, and thinking creates the others. |
| 9568 | I prefer the open sentences of a Constructibility Theory, to Platonist ideas of 'equivalence classes' [Chihara] |
| Full Idea: What I refer to as an 'equivalence class' (of line segments of a particular length) is an open sentence in my Constructibility Theory. I just use this terminology of the Platonist for didactic purposes. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 09.10) | |
| A reaction: This is because 'equivalence classes' is committed to the existence of classes, which is Quinean Platonism. I am with Chihara in wanting a story that avoids such things. Kit Fine is investigating similar notions of rules of construction. |
| 9547 | Mathematical entities are causally inert, so the causal theory of reference won't work for them [Chihara] |
| Full Idea: Causal theories of reference seem doomed to failure for the case of reference to mathematical entities, since such entities are evidently causally inert. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], 01.3) | |
| A reaction: Presumably you could baptise a fictional entity such as 'Polonius', and initiate a social causal chain, with a tradition of reference. You could baptise a baby in absentia. |
| 4937 | Systems that generate a sense of value are basic to the primitive brain [Edelman/Tononi] |
| Full Idea: Early and central in the development of the brain are the dimensions provided by value systems indicating salience for the entire organism. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.13) | |
| A reaction: This doesn't quite meet Hume's challenge to find values in the whole of nature, but it matches Charles Taylor's claim that for humans values are knowable a priori. Conditional values can be facts of the whole of nature. "If there is life, x has value..". |
| 6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |
| Full Idea: Hermarchus said that animal killing is justified by considerations of human safety and nourishment and by animals' inability to form contractual relations of justice with us. | |
| From: report of Hermarchus (fragments/reports [c.270 BCE]) by David A. Sedley - Hermarchus | |
| A reaction: Could the last argument be used to justify torturing animals? Or could we eat a human who was too brain-damaged to form contracts? |
| 9574 | 'Gunk' is an individual possessing no parts that are atoms [Chihara] |
| Full Idea: An 'atomless gunk' is defined to be an individual possessing no parts that are atoms. | |
| From: Charles Chihara (A Structural Account of Mathematics [2004], App A) | |
| A reaction: [Lewis coined it] If you ask what are a-toms made of and what are ideas made of, the only answer we can offer is that the a-toms are made of gunk, and the ideas aren't made of anything, which is still bad news for the existence of ideas. |