122 ideas
| 7893 | Our life is the creation of our mind [Anon (Dham)] |
| Full Idea: What we are today comes from our thoughts of yesterday, and our present thoughts build our life of tomorrow: our life is the creation of our mind. | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §1.1) | |
| A reaction: I may adopt this as a second epigraph for the database. This idea records the subjective view, which now comes up against evolutionary psychology. Maybe philosophy is opposed to science, because it is committed to exploring the subjective view? |
| 2546 | Philosophy is a magnificent failure in its attempt to overstep the limits of our knowledge [McGinn] |
| Full Idea: Philosophy marks the limits of human theoretical intelligence. Philosophy is an attempt to overstep our cognitive bounds, a kind of magnificent failure. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.209) | |
| A reaction: No one attempts to overstep boundaries once they are confirmed as such. The magnificent attempts persist because failure is impossible to demonstrate (except, perhaps, by Gödel's Theorem). |
| 17892 | For clear questions posed by reason, reason can also find clear answers [Gödel] |
| Full Idea: I uphold the belief that for clear questions posed by reason, reason can also find clear answers. | |
| From: Kurt Gödel (works [1930]), quoted by Peter Koellner - On the Question of Absolute Undecidability 1.5 | |
| A reaction: [written in 1961] This contradicts the implication normally taken from his much earlier Incompleteness Theorems. |
| 6052 | Definitions identify two concepts, so they presuppose identity [McGinn] |
| Full Idea: Any definition must presuppose the notion of identity precisely because a definition affirms the identity of two concepts. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: McGinn is arguing that identity is fundamental to thought, and this seems persuasive. It may be, though, that while identities are inescapable, definitions are impossible. |
| 10041 | Impredicative Definitions refer to the totality to which the object itself belongs [Gödel] |
| Full Idea: Impredicative Definitions are definitions of an object by reference to the totality to which the object itself (and perhaps also things definable only in terms of that object) belong. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], n 13) |
| 6064 | Regresses are only vicious in the context of an explanation [McGinn] |
| Full Idea: Regresses are only vicious in the context of some explanatory aim, not in themselves. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2 n11) | |
| A reaction: A nice point. It is not quite clear how 'pure' reason could ever be vicious, or charming, or sycophantic. The problem about a vicious regress is precisely that it fails to explain anything. Now benign regresses are something else… (see Idea 2523) |
| 6088 | Truth is a method of deducing facts from propositions [McGinn] |
| Full Idea: Truth is essentially a method of deducing facts from propositions. | |
| From: Colin McGinn (Logical Properties [2000], Ch.5) | |
| A reaction: Very persuasive. McGinn is offering a disquotational account of truth, but in a robust form. Of course, deduction normally takes the form of moving infallibly from one truth to another, but that model of deduction won't fit this particular proposal. |
| 6084 | 'Snow does not fall' corresponds to snow does fall [McGinn] |
| Full Idea: We can say that the proposition that snow does not fall from the sky corresponds to the fact that snow does fall from the sky - in the sense that there is a mapping from fact to proposition. | |
| From: Colin McGinn (Logical Properties [2000], Ch.5) | |
| A reaction: A very nice difficulty for the correspondence theory. It becomes essential to say how the two things correspond before it can offer any sort of account of the truth-relation. |
| 6085 | The idea of truth is built into the idea of correspondence [McGinn] |
| Full Idea: The correspondence theory has an air of triviality, and hence undeniability, but this is because it implicitly builds the idea of truth into the notion of correspondence. | |
| From: Colin McGinn (Logical Properties [2000], Ch.5) | |
| A reaction: If this is accepted, it is a really fatal objection to the theory. Russell tried to use the idea of 'congruency' between beliefs and reality, but that may be open to the same objection. McGinn is claiming that truth is essentially indefinable. |
| 6083 | The coherence theory of truth implies idealism, because facts are just coherent beliefs [McGinn] |
| Full Idea: If 'snow falls from the sky' is true iff it coheres with other beliefs, this is a form of idealism; snow could surely fall from sky even if there were no beliefs in the world to cohere with each other. | |
| From: Colin McGinn (Logical Properties [2000], Ch.5) | |
| A reaction: The coherence theory of truth strikes me as yet another blunder involving a confusion of ontology and epistemology. Of course, idealism may be true, but I have yet to hear a good reason why I should abandon commonsense realism. |
| 21752 | Prior to Gödel we thought truth in mathematics consisted in provability [Gödel, by Quine] |
| Full Idea: Gödel's proof wrought an abrupt turn in the philosophy of mathematics. We had supposed that truth, in mathematics, consisted in provability. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Willard Quine - Forward to Gödel's Unpublished | |
| A reaction: This explains the crisis in the early 1930s, which Tarski's theory appeared to solve. |
| 6086 | Truth is the property of propositions that makes it possible to deduce facts [McGinn] |
| Full Idea: Truth is a property of a proposition from which one can deduce the fact stated by the proposition. | |
| From: Colin McGinn (Logical Properties [2000], Ch.5) | |
| A reaction: This is McGinn's explanation of the disquotational account of truth ('p' is true iff p). The redundancy theorist would reply that you can deduce p from 'p' without mentioning truth, but it remains to ask why this deduction is possible. |
| 6087 | Without the disquotation device for truth, you could never form beliefs from others' testimony [McGinn] |
| Full Idea: Imagine being in a community which had no concept of truth; ..you cannot disquote on p and hence form beliefs about the world as a result of testimony, since you lack the device of disquotation that is the essence of truth. | |
| From: Colin McGinn (Logical Properties [2000], Ch.5) | |
| A reaction: Whether his theory is right or not, the observation that testimony is the really crucial area where we must have a notion of truth is very good. How about 'truth is what turns propositions into beliefs'? |
| 17751 | Gödel proved the completeness of first order predicate logic in 1930 [Gödel, by Walicki] |
| Full Idea: Gödel proved the completeness of first order predicate logic in his doctoral dissertation of 1930. | |
| From: report of Kurt Gödel (Completeness of Axioms of Logic [1930]) by Michal Walicki - Introduction to Mathematical Logic History E.2.2 |
| 17835 | Gödel show that the incompleteness of set theory was a necessity [Gödel, by Hallett,M] |
| Full Idea: Gödel's incompleteness results of 1931 show that all axiom systems precise enough to satisfy Hilbert's conception are necessarily incomplete. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Michael Hallett - Introduction to Zermelo's 1930 paper p.1215 | |
| A reaction: [Hallett italicises 'necessarily'] Hilbert axioms have to be recursive - that is, everything in the system must track back to them. |
| 8679 | We perceive the objects of set theory, just as we perceive with our senses [Gödel] |
| Full Idea: We have something like perception of the objects of set theory, shown by the axioms forcing themselves on us as being true. I don't see why we should have less confidence in this kind of perception (i.e. mathematical intuition) than in sense perception. | |
| From: Kurt Gödel (What is Cantor's Continuum Problem? [1964], p.483), quoted by Michčle Friend - Introducing the Philosophy of Mathematics 2.4 | |
| A reaction: A famous strong expression of realism about the existence of sets. It is remarkable how the ingredients of mathematics spread themselves before the mind like a landscape, inviting journeys - but I think that just shows how minds cope with abstractions. |
| 9942 | Gödel proved the classical relative consistency of the axiom V = L [Gödel, by Putnam] |
| Full Idea: Gödel proved the classical relative consistency of the axiom V = L (which implies the axiom of choice and the generalized continuum hypothesis). This established the full independence of the continuum hypothesis from the other axioms. | |
| From: report of Kurt Gödel (What is Cantor's Continuum Problem? [1964]) by Hilary Putnam - Mathematics without Foundations | |
| A reaction: Gödel initially wanted to make V = L an axiom, but the changed his mind. Maddy has lots to say on the subject. |
| 21716 | In simple type theory the axiom of Separation is better than Reducibility [Gödel, by Linsky,B] |
| Full Idea: In the superior realist and simple theory of types, the place of the axiom of reducibility is not taken by the axiom of classes, Zermelo's Aussonderungsaxiom. | |
| From: report of Kurt Gödel (Russell's Mathematical Logic [1944], p.140-1) by Bernard Linsky - Russell's Metaphysical Logic 6.1 n3 | |
| A reaction: This is Zermelo's Axiom of Separation, but that too is not an axiom of standard ZFC. |
| 9188 | Gödel proved that first-order logic is complete, and second-order logic incomplete [Gödel, by Dummett] |
| Full Idea: Gödel proved the completeness of standard formalizations of first-order logic, including Frege's original one. However, an implication of his famous theorem on the incompleteness of arithmetic is that second-order logic is incomplete. | |
| From: report of Kurt Gödel (works [1930]) by Michael Dummett - The Philosophy of Mathematics 3.1 | |
| A reaction: This must mean that it is impossible to characterise arithmetic fully in terms of first-order logic. In which case we can only characterize the features of abstract reality in general if we employ an incomplete system. We're doomed. |
| 10035 | Mathematical Logic is a non-numerical branch of mathematics, and the supreme science [Gödel] |
| Full Idea: 'Mathematical Logic' is a precise and complete formulation of formal logic, and is both a section of mathematics covering classes, relations, symbols etc, and also a science prior to all others, with ideas and principles underlying all sciences. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], p.447) | |
| A reaction: He cites Leibniz as the ancestor. In this database it is referred to as 'theory of logic', as 'mathematical' seems to be simply misleading. The principles of the subject are standardly applied to mathematical themes. |
| 6051 | In 'x is F and x is G' we must assume the identity of x in the two statements [McGinn] |
| Full Idea: If we say 'for some x, x is F and x is G' we are making tacit appeal to the idea of identity in using 'x' twice here: it has to be the same object that is both F and G. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: This may well be broadened to any utterances whatsoever. The only remaining question is to speculate about whether it is possible to think without identities. The Hopi presumably gave identity to processes rather objects. How does God think? |
| 6055 | Both non-contradiction and excluded middle need identity in their formulation [McGinn] |
| Full Idea: To formulate the law of non-contradiction ('nothing can be both F and non-F') and the law of excluded middle ('everything is either F or it is not-F'), we need the concept of identity (in 'nothing' and 'everything'). | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: Two good examples in McGinn's argument that identity is basic to all thinking. But the argument also works to say that necessity is basic (since both laws claim it) and properties are basic. Let's just declare everything 'basic', and we can all go home. |
| 6059 | Identity is unitary, indefinable, fundamental and a genuine relation [McGinn] |
| Full Idea: I have endorsed four main theses about identity: it is unitary, it is indefinable, it is fundamental, and it is a genuine relation | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: That it is fundamental to our thinking seems certain (but to all possible thought?). That it is a relation looks worth questioning. One might challenge unitary by comparing the identity of numbers, values, electrons and continents. I can't define it. |
| 2544 | Thoughts have a dual aspect: as they seem to introspection, and their underlying logical reality [McGinn] |
| Full Idea: Our thoughts have a kind of duality, corresponding to their surface appearance to introspection and their underlying logical reality. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.147) |
| 6067 | Existential quantifiers just express the quantity of things, leaving existence to the predicate 'exists' [McGinn] |
| Full Idea: What the existential quantifier does is indicate the quantity of things in question - it says that some are; it is left up to the predicate 'exists' to express existence. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: This seems right. The whole quantification business seems like a conjuring trick to conceal the embarrassingly indefinable and 'metaphysical' notion of 'existence'. Cf Idea 7697. |
| 6042 | The quantifier is overrated as an analytical tool [McGinn] |
| Full Idea: The quantifier has been overrated as a tool of logical and linguistic analysis. | |
| From: Colin McGinn (Logical Properties [2000], Pref) | |
| A reaction: I find this proposal quite thrilling. Twentieth century analytical philosophy has been in thrall to logic, giving the upper hand in philosophical discussion to the logicians, who are often not very good at philosophy. |
| 10042 | Reference to a totality need not refer to a conjunction of all its elements [Gödel] |
| Full Idea: One may, on good grounds, deny that reference to a totality necessarily implies reference to all single elements of it or, in other words, that 'all' means the same as an infinite logical conjunction. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], p.455) |
| 6069 | 'Partial quantifier' would be a better name than 'existential quantifier', as no existence would be implied [McGinn] |
| Full Idea: We would do much better to call 'some' the 'partial quantifier' (rather than the 'existential quantifier'), on analogy with the universal quantifier - as neither of them logically implies existence. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: Like McGinn's other suggestions in this chapter, this strikes me as a potentially huge clarification in linguistic analysis. I wait with interest to see whether the philosophical logicians take it up. I bet they don't. |
| 6068 | We need an Intentional Quantifier ("some of the things we talk about.."), so existence goes into the proposition [McGinn] |
| Full Idea: We could introduce an 'intentional quantifier' (Ix) which means 'some of the things we talk about..'; we could then say 'some of the things we talk about are F and exist' (Ix, x is F and x exists). | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: This immediately strikes me as a promising contribution to the analytical toolkit. McGinn is supporting his view that existence is a predicate, and so belongs inside the proposition, not outside. |
| 10620 | Originally truth was viewed with total suspicion, and only demonstrability was accepted [Gödel] |
| Full Idea: At that time (c.1930) a concept of objective mathematical truth as opposed to demonstrability was viewed with greatest suspicion and widely rejected as meaningless. | |
| From: Kurt Gödel (works [1930]), quoted by Peter Smith - Intro to Gödel's Theorems 28.2 | |
| A reaction: [quoted from a letter] This is the time of Ramsey's redundancy account, and before Tarski's famous paper of 1933. It is also the high point of Formalism, associated with Hilbert. |
| 17886 | The limitations of axiomatisation were revealed by the incompleteness theorems [Gödel, by Koellner] |
| Full Idea: The inherent limitations of the axiomatic method were first brought to light by the incompleteness theorems. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Peter Koellner - On the Question of Absolute Undecidability 1.1 |
| 10071 | Second Incompleteness: nice theories can't prove their own consistency [Gödel, by Smith,P] |
| Full Idea: Second Incompleteness Theorem: roughly, nice theories that include enough basic arithmetic can't prove their own consistency. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Peter Smith - Intro to Gödel's Theorems 1.5 | |
| A reaction: On the face of it, this sounds less surprising than the First Theorem. Philosophers have often noticed that it seems unlikely that you could use reason to prove reason, as when Descartes just relies on 'clear and distinct ideas'. |
| 19123 | If soundness can't be proved internally, 'reflection principles' can be added to assert soundness [Gödel, by Halbach/Leigh] |
| Full Idea: Gödel showed PA cannot be proved consistent from with PA. But 'reflection principles' can be added, which are axioms partially expressing the soundness of PA, by asserting what is provable. A Global Reflection Principle asserts full soundness. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Halbach,V/Leigh,G.E. - Axiomatic Theories of Truth (2013 ver) 1.2 | |
| A reaction: The authors point out that this needs a truth predicate within the language, so disquotational truth won't do, and there is a motivation for an axiomatic theory of truth. |
| 17883 | Gödel's Theorems did not refute the claim that all good mathematical questions have answers [Gödel, by Koellner] |
| Full Idea: Gödel was quick to point out that his original incompleteness theorems did not produce instances of absolute undecidability and hence did not undermine Hilbert's conviction that for every precise mathematical question there is a discoverable answer. | |
| From: report of Kurt Gödel (works [1930]) by Peter Koellner - On the Question of Absolute Undecidability Intro | |
| A reaction: The normal simplistic view among philosophes is that Gödel did indeed decisively refute the optimistic claims of Hilbert. Roughly, whether Hilbert is right depends on which axioms of set theory you adopt. |
| 17888 | The undecidable sentence can be decided at a 'higher' level in the system [Gödel] |
| Full Idea: My undecidable arithmetical sentence ...is not at all absolutely undecidable; rather, one can always pass to 'higher' systems in which the sentence in question is decidable. | |
| From: Kurt Gödel (On Formally Undecidable Propositions [1931]), quoted by Peter Koellner - On the Question of Absolute Undecidability 1.1 | |
| A reaction: [a 1931 MS] He says the reals are 'higher' than the naturals, and the axioms of set theory are higher still. The addition of a truth predicate is part of what makes the sentence become decidable. |
| 10621 | Gödel's First Theorem sabotages logicism, and the Second sabotages Hilbert's Programme [Smith,P on Gödel] |
| Full Idea: Where Gödel's First Theorem sabotages logicist ambitions, the Second Theorem sabotages Hilbert's Programme. | |
| From: comment on Kurt Gödel (On Formally Undecidable Propositions [1931]) by Peter Smith - Intro to Gödel's Theorems 36 | |
| A reaction: Neo-logicism (Crispin Wright etc.) has a strategy for evading the First Theorem. |
| 10038 | A logical system needs a syntactical survey of all possible expressions [Gödel] |
| Full Idea: In order to be sure that new expression can be translated into expressions not containing them, it is necessary to have a survey of all possible expressions, and this can be furnished only by syntactical considerations. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], p.448) | |
| A reaction: [compressed] |
| 18062 | Set-theory paradoxes are no worse than sense deception in physics [Gödel] |
| Full Idea: The set-theoretical paradoxes are hardly any more troublesome for mathematics than deceptions of the senses are for physics. | |
| From: Kurt Gödel (What is Cantor's Continuum Problem? [1964], p.271), quoted by Philip Kitcher - The Nature of Mathematical Knowledge 03.4 |
| 10132 | There can be no single consistent theory from which all mathematical truths can be derived [Gödel, by George/Velleman] |
| Full Idea: Gödel's far-reaching work on the nature of logic and formal systems reveals that there can be no single consistent theory from which all mathematical truths can be derived. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.8 |
| 10046 | The generalized Continuum Hypothesis asserts a discontinuity in cardinal numbers [Gödel] |
| Full Idea: The generalized Continuum Hypothesis says that there exists no cardinal number between the power of any arbitrary set and the power of the set of its subsets. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], p.464) |
| 10868 | The Continuum Hypothesis is not inconsistent with the axioms of set theory [Gödel, by Clegg] |
| Full Idea: Gödel proved that the Continuum Hypothesis was not inconsistent with the axioms of set theory. | |
| From: report of Kurt Gödel (What is Cantor's Continuum Problem? [1964]) by Brian Clegg - Infinity: Quest to Think the Unthinkable Ch.15 |
| 13517 | If set theory is consistent, we cannot refute or prove the Continuum Hypothesis [Gödel, by Hart,WD] |
| Full Idea: Gödel proved that (if set theory is consistent) we cannot refute the continuum hypothesis, and Cohen proved that (if set theory is consistent) we cannot prove it either. | |
| From: report of Kurt Gödel (What is Cantor's Continuum Problem? [1964]) by William D. Hart - The Evolution of Logic 10 |
| 17885 | Gödel eventually hoped for a generalised completeness theorem leaving nothing undecidable [Gödel, by Koellner] |
| Full Idea: Eventually Gödel ...expressed the hope that there might be a generalised completeness theorem according to which there are no absolutely undecidable sentences. | |
| From: report of Kurt Gödel (works [1930]) by Peter Koellner - On the Question of Absolute Undecidability Intro | |
| A reaction: This comes as a bit of a shock to those who associate him with the inherent undecidability of reality. |
| 10614 | The real reason for Incompleteness in arithmetic is inability to define truth in a language [Gödel] |
| Full Idea: The concept of truth of sentences in a language cannot be defined in the language. This is the true reason for the existence of undecidable propositions in the formal systems containing arithmetic. | |
| From: Kurt Gödel (works [1930]), quoted by Peter Smith - Intro to Gödel's Theorems 21.6 | |
| A reaction: [from a letter by Gödel] So they key to Incompleteness is Tarski's observations about truth. Highly significant, as I take it. |
| 10072 | First Incompleteness: arithmetic must always be incomplete [Gödel, by Smith,P] |
| Full Idea: First Incompleteness Theorem: any properly axiomatised and consistent theory of basic arithmetic must remain incomplete, whatever our efforts to complete it by throwing further axioms into the mix. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Peter Smith - Intro to Gödel's Theorems 1.2 | |
| A reaction: This is because it is always possible to formulate a well-formed sentence which is not provable within the theory. |
| 3198 | Gödel showed that arithmetic is either incomplete or inconsistent [Gödel, by Rey] |
| Full Idea: Gödel's theorem states that either arithmetic is incomplete, or it is inconsistent. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Georges Rey - Contemporary Philosophy of Mind 8.7 |
| 9590 | Arithmetical truth cannot be fully and formally derived from axioms and inference rules [Gödel, by Nagel/Newman] |
| Full Idea: The vast continent of arithmetical truth cannot be brought into systematic order by laying down a fixed set of axioms and rules of inference from which every true mathematical statement can be formally derived. For some this was a shocking revelation. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by E Nagel / JR Newman - Gödel's Proof VII.C | |
| A reaction: Good news for philosophy, I'd say. The truth cannot be worked out by mechanical procedures, so it needs the subtle and intuitive intelligence of your proper philosopher (Parmenides is the role model) to actually understand reality. |
| 11069 | Gödel's Second says that semantic consequence outruns provability [Gödel, by Hanna] |
| Full Idea: Gödel's Second Incompleteness Theorem says that true unprovable sentences are clearly semantic consequences of the axioms in the sense that they are necessarily true if the axioms are true. So semantic consequence outruns provability. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Robert Hanna - Rationality and Logic 5.3 |
| 10118 | First Incompleteness: a decent consistent system is syntactically incomplete [Gödel, by George/Velleman] |
| Full Idea: First Incompleteness Theorem: If S is a sufficiently powerful formal system, then if S is consistent then S is syntactically incomplete. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.6 | |
| A reaction: Gödel found a single sentence, effectively saying 'I am unprovable in S', which is neither provable nor refutable in S. |
| 10122 | Second Incompleteness: a decent consistent system can't prove its own consistency [Gödel, by George/Velleman] |
| Full Idea: Second Incompleteness Theorem: If S is a sufficiently powerful formal system, then if S is consistent then S cannot prove its own consistency | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.6 | |
| A reaction: This seems much less surprising than the First Theorem (though it derives from it). It was always kind of obvious that you couldn't use reason to prove that reason works (see, for example, the Cartesian Circle). |
| 10611 | There is a sentence which a theory can show is true iff it is unprovable [Gödel, by Smith,P] |
| Full Idea: The original Gödel construction gives us a sentence that a theory shows is true if and only if it satisfies the condition of being unprovable-in-that-theory. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Peter Smith - Intro to Gödel's Theorems 20.5 |
| 10867 | 'This system can't prove this statement' makes it unprovable either way [Gödel, by Clegg] |
| Full Idea: An approximation of Gödel's Theorem imagines a statement 'This system of mathematics can't prove this statement true'. If the system proves the statement, then it can't prove it. If the statement can't prove the statement, clearly it still can't prove it. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Brian Clegg - Infinity: Quest to Think the Unthinkable Ch.15 | |
| A reaction: Gödel's contribution to this simple idea seems to be a demonstration that formal arithmetic is capable of expressing such a statement. |
| 10039 | Some arithmetical problems require assumptions which transcend arithmetic [Gödel] |
| Full Idea: It has turned out that the solution of certain arithmetical problems requires the use of assumptions essentially transcending arithmetic. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], p.449) | |
| A reaction: A nice statement of the famous result, from the great man himself, in the plainest possible English. |
| 10043 | Mathematical objects are as essential as physical objects are for perception [Gödel] |
| Full Idea: Classes and concepts may be conceived of as real objects, ..and are as necessary to obtain a satisfactory system of mathematics as physical bodies are necessary for a satisfactory theory of our sense perceptions, with neither case being about 'data'. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], p.456) | |
| A reaction: Note that while he thinks real objects are essential for mathematics, be may not be claiming the same thing for our knowledge of logic. If logic contains no objects, then how could mathematics be reduced to it, as in logicism? |
| 10271 | Basic mathematics is related to abstract elements of our empirical ideas [Gödel] |
| Full Idea: Evidently the 'given' underlying mathematics is closely related to the abstract elements contained in our empirical ideas. | |
| From: Kurt Gödel (What is Cantor's Continuum Problem? [1964], Suppl) | |
| A reaction: Yes! The great modern mathematical platonist says something with which I can agree. He goes on to hint at a platonic view of the structure of the empirical world, but we'll let that pass. |
| 10045 | Impredicative definitions are admitted into ordinary mathematics [Gödel] |
| Full Idea: Impredicative definitions are admitted into ordinary mathematics. | |
| From: Kurt Gödel (Russell's Mathematical Logic [1944], p.464) | |
| A reaction: The issue is at what point in building an account of the foundations of mathematics (if there be such, see Putnam) these impure definitions should be ruled out. |
| 8747 | Realists are happy with impredicative definitions, which describe entities in terms of other existing entities [Gödel, by Shapiro] |
| Full Idea: Gödel defended impredicative definitions on grounds of ontological realism. From that perspective, an impredicative definition is a description of an existing entity with reference to other existing entities. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Stewart Shapiro - Thinking About Mathematics 5.3 | |
| A reaction: This is why constructivists must be absolutely precise about definition, where realists only have to do their best. Compare building a car with painting a landscape. |
| 6070 | Existence is a primary quality, non-existence a secondary quality [McGinn] |
| Full Idea: Existence is like a primary quality; non-existence is like a secondary quality. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2 n29) | |
| A reaction: Since McGinn thinks existence really is a property, and hence, presumably, a predicate, I don't quite see why he uses the word "like". A nicely pithy and thought-provoking remark. |
| 6062 | Existence can't be analysed as instantiating a property, as instantiation requires existence [McGinn] |
| Full Idea: Paraphrasing existence statements into statements about the instantiation of a property does not establish that existence is not a predicate, since the notion of instantiation must be taken to have existence built into it. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: Thank you, Colin McGinn! This now strikes me as so obvious that it is astonishing that for the whole of the twentieth century no one seems to have said it. For a century philosophers had swept the ontological dirt under the mat. |
| 6065 | We can't analyse the sentence 'something exists' in terms of instantiated properties [McGinn] |
| Full Idea: The problems of the orthodox view are made vivid by analysis of the sentence 'something exists'; this is meaningful and true, but what property are we saying is instantiated here? | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: A very nice point. McGinn claims that existence is a property, a very generalised one. Personally I don't think anyone is even remotely clear what a property is, so the whole discussion is a bit premature. Must properties have causal powers? |
| 22427 | To explain object qualities, primary qualities must be more than mere sources of experience [McGinn] |
| Full Idea: In order that we have available an explanation of the qualities of objects we need to be able to conceive primary qualities as consisting in something other than powers to produce experiences. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6 n 52) | |
| A reaction: I suppose if the qualities are nothing more than the source of the experiences, that is Kant's noumenon. Nothing more could be said. The seems to be a requirement for tacit inference here. We infer the interior of the tomato. |
| 6082 | If causal power is the test for reality, that will exclude necessities and possibilities [McGinn] |
| Full Idea: Whether my body weight is necessary or contingent makes no difference at all to my causal powers, so modality is epiphenomenal; if you took causal potential as a test of reality you would have to declare modes unreal. | |
| From: Colin McGinn (Logical Properties [2000], Ch.4) | |
| A reaction: We could try analysing modality into causal terms, as Lewis proposes with quantification across worlds, or as Quine proposes by reduction to natural regularities. I am not sure what it would mean to declare that modes are 'real'. |
| 6075 | Facts are object-plus-extension, or property-plus-set-of-properties, or object-plus-property [McGinn] |
| Full Idea: A fact may be an object and an extension (Quine's view), or a property and a set of properties, or an object and a property; the view I favour is the third one, which seems the most natural. | |
| From: Colin McGinn (Logical Properties [2000], Ch.3) | |
| A reaction: Personally I tend to use the word 'fact' in a realist and non-linguistic way. There must be innumerable inexpressible facts, such as the single pattern made by all the particles of the universe. McGinn seems to be talking of 'atomic facts'. See Idea 6111. |
| 18892 | Suppose a world where I'm from different gametes; add my gametes; which one is more me? [McGinn] |
| Full Idea: It seems essential that you come from your gametes. Suppose (for reductio) that I come from Nixon's actual gametes. Now add my actual gametes to that possible world, and suppose they become an adult. Which has the stronger title to be me? | |
| From: Colin McGinn (On the Necessity of Origin [1976], p.132), quoted by Nathan Salmon - Reference and Essence (1st edn) 7.25.5 | |
| A reaction: [See Nathan Salmon 1981:209] Feels like the Ship of Theseus. You say 'that's Theseus Ship', until the rival ship appears around the headland. Confusion. If Nixon's gametes can produce McGinn, the second gametes could produce a Nixon! Then what? |
| 12019 | McGinn falsely claims necessity of origin is a special case of the necessity of identity [Forbes,G on McGinn] |
| Full Idea: McGinn assimilates the origin relation among organisms to the identity relation, so that the necessity of origin becomes a special case of the necessity of identity. We argue that this assimilation is illegitimate. | |
| From: comment on Colin McGinn (On the Necessity of Origin [1976]) by Graeme Forbes - The Metaphysics of Modality 6.1 | |
| A reaction: Not sure about this. I have long suspected what McGinn suspects. Once you have identified the organism with a particular origin, it hardly seems surprising that this particular origin has become inescapable. |
| 6058 | Identity propositions are not always tautological, and have a key epistemic role [McGinn] |
| Full Idea: Identity propositions are not always analytic or a priori (as Frege long ago taught us) so there is nothing trivial about such propositions; the claim of redundancy ignores the epistemic role that the concept of identity plays. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: He is referring to Frege's Morning Star/Evening Star distinction (Idea 4972). Wittgenstein wanted to eliminate our basic metaphysics by relabelling it as analytic or tautological, but his project failed. Long live metaphysics! |
| 6053 | Identity is as basic as any concept could ever be [McGinn] |
| Full Idea: Identity has a universality and basicness that is hard to overstate; concepts don't get more basic than this - or more indispensable. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: I agree with this. It seems to me to follow that the natural numbers are just as basic, because they are entailed by the separateness of the identities of things. And the whole of mathematics is the science of the patterns within these numbers. |
| 6043 | Type-identity is close similarity in qualities [McGinn] |
| Full Idea: Two things are said to be type-identical when they are similar enough to be declared qualitatively identical. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: A simple point which brings out the fact that type-identity is unlikely to be any sort of true identity (unless there is absolutely no different at all between two electrons, say). |
| 6045 | It is best to drop types of identity, and speak of 'identity' or 'resemblance' [McGinn] |
| Full Idea: It would be better to drop talk of 'numerical' and 'qualitative' identity altogether, speaking instead simply of identity and resemblance. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1 n4) | |
| A reaction: This is the kind of beautifully simple proposal I pay analytical philosophers to come up with. I will attempt in future to talk either of 'identity' (which is strict), or 'resemblance' (which comes in degrees). |
| 6044 | Qualitative identity is really numerical identity of properties [McGinn] |
| Full Idea: A statement of so-called qualitative identity is really a statement of numerical identity (that is, identity tout court) about the properties of the objects in question - assuming that there are genuine universals. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: We might agree that two cars are type-identical, even though (under the microscope) we decided that none of their properties were absolutely identical. |
| 6046 | Qualitative identity can be analysed into numerical identity of the type involved [McGinn] |
| Full Idea: We can analyse qualitative identity in terms of numerical identity, by saying that x and y are type-identical if there is a single type T that x and y both are, i.e. they both exemplify the same type. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: This just seems to shift the problem onto the words 'are' and 'exemplify'. This takes us back to the problem of things 'partaking' of Plato's Forms. Better to say that qualitative identity isn't identity - it is resemblance (see Idea 6045). |
| 6054 | Sherlock Holmes does not exist, but he is self-identical [McGinn] |
| Full Idea: Sherlock Holmes does not exist, but he is self-identical (he is certainly not indentical to Dr Watson). | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: Most significant. Identity does not entail existence; identity is necessary for existence (I think) but not sufficient. But the notion of existence might be prior to the notion of identity, and the creation of Holmes be parasitic on real existence. |
| 6066 | Existence is a property of all objects, but less universal than self-identity, which covers even conceivable objects [McGinn] |
| Full Idea: Existence is a property universal to all objects that exist, somewhat like self-identity, but less universal, because self-identity holds of all conceivable objects, not merely those that happen to exist. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: This is a splendidly defiant response to the Kantian slogan that 'existence is not a predicate', and I find McGinn persuasive. I can still not find anyone to explain to me exactly what a property is, so I will reserve judgement. |
| 6047 | All identity is necessary, though identity statements can be contingently true [McGinn] |
| Full Idea: All identity is necessary, although there can be contingently true identity statements - those that contain non-rigid designators. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1 n5) | |
| A reaction: A nice case of the need to keep epistemology and ontology separate. An example might be 'The Prime Minister wears a wig', where 'Prime Minister' may not be a rigid designator. 'Winston wears a wig' will be necessary, if true (which it wasn't). |
| 6048 | Leibniz's Law is so fundamental that it almost defines the concept of identity [McGinn] |
| Full Idea: Leibniz's Law, which a defender of relative identity might opt to reject, is so fundamental to the notion of identity that rejecting it amounts to changing the subject. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1 n8) | |
| A reaction: The Law here is the 'indiscernibility of identicals'. I agree with McGinn, and anyone who loses their grip on this notion of identity strikes me as losing all grip on reality, and threatening their own sanity (well, call it their 'philosophical sanity'). |
| 6049 | Leibniz's Law says 'x = y iff for all P, Px iff Py' [McGinn] |
| Full Idea: Leibniz's Law says 'x = y iff for all P, Px iff Py'. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: That is, two things are the same if when we say that one thing (x) has a property (P), then we are saying that the other thing (y) also has the property. A usefully concise statement of the Law. |
| 6050 | Leibniz's Law presupposes the notion of property identity [McGinn] |
| Full Idea: Leibniz's Law presupposes the notion of property identity. | |
| From: Colin McGinn (Logical Properties [2000], Ch.1) | |
| A reaction: A very important observation, because it leads to recognition of the way in which basic concepts and categories of thought interconnect. Which is more metaphysically basic, identity or properties? It is not easy to say… |
| 6080 | Modality is not objects or properties, but the type of binding of objects to properties [McGinn] |
| Full Idea: Modality has a special ontological category: it consists neither in objects (possible worlds theory) nor in properties (predicate modifier view), but items I have called 'modes', ..which can be hard/soft/rigid/pliable binding of objects to properties. | |
| From: Colin McGinn (Logical Properties [2000], Ch.4) | |
| A reaction: As so often, McGinn is very persuasive. Essentially he is proposing that modality is adverbial. He associates the middle view with David Wiggins. |
| 6079 | If 'possible' is explained as quantification across worlds, there must be possible worlds [McGinn] |
| Full Idea: If we replace modal words like 'possible' with quantification across worlds, clearly the notion of 'world' must exclude impossible worlds, otherwise 'possibly p' will be true if 'p' holds in an impossible world. | |
| From: Colin McGinn (Logical Properties [2000], Ch.4) | |
| A reaction: The point here, of course, is that the question is being begged of what 'possible' and 'impossible' actually mean. |
| 6171 | Beliefs are states of the head that explain behaviour, and also items with referential truth-conditions [McGinn] |
| Full Idea: We view beliefs both as states of the head explanatory of behaviour, and as items possessed of referential truth-conditions. | |
| From: Colin McGinn (The Structure of Content [1982]), quoted by Mark Rowlands - Externalism Ch.6 | |
| A reaction: McGinn wants to build a two-part account of meaning on this point, which Rowlands resists. Hume just wanted to define belief by a feeling, but it seems obvious that truth must also be involved. |
| 7898 | The world is just the illusion of an appearance [Anon (Dham)] |
| Full Idea: When a man considers this world as a bubble of froth, and as the illusion of an appearance, then the king of death has no power over him. | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §13.170) | |
| A reaction: Strictly, of course, this says you can 'consider' things this way. Perhaps we could substitute 'pretends', but the world's great religions don't go in for that sort of thing. Berkeley would be shocked to learn he was approaching Buddhism. |
| 22413 | Being red simply consists in looking red [McGinn] |
| Full Idea: What we should claim is that being red consists in looking red. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: A very nice simple account. There is more to being square than looking square (which may not even guarantee that it is square). That's the primary/secondary distinction in a nut shell. But red things don't look red in the dark. Sufficient, not necessary. |
| 22415 | Relativity means differing secondary perceptions are not real disagreements [McGinn] |
| Full Idea: Relativity permits differences in the perceived secondary qualities not to imply genuine disagreement, whereas perceived differences of primary qualities imply that at least one perceiver is in error. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: An example of 'relativity' is colour blindness. Sounds good, but what of one perceiver seeing a square as square, and another seeing it obliquely as a parallelogram? The squareness then seems more like a theory than a perception. |
| 22416 | Phenomenalism is correct for secondary qualities, so scepticism is there impossible [McGinn] |
| Full Idea: We might say that scepticism is ruled out for secondary qualities because (roughly) phenomenalism is correct for them; but phenomenalism is not similarly correct for primary qualities, and scepticism cannot get a foothold. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: An odd idea, if phenomenalism says that reality consists entirely of phenomena. I should think phenomenalism is a commitment to the absence of primary qualities. |
| 22422 | Maybe all possible sense experience must involve both secondary and primary qualities [McGinn] |
| Full Idea: The inseparability thesis about perception says that for any actual and possible sense the content of experiences delivered by that sense must be both of secondary qualities and of primary qualities. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: That would mean that all possible experience must have a mode of presentation, and also must be 'of' something independent of experience. So a yellow after-image would not count as an 'experience'? |
| 22428 | You understood being red if you know the experience involved; not so with thngs being square [McGinn] |
| Full Idea: To grasp what it is to be red is to know the kind of sensory experience red things produce; ...but it is not true that to grasp what it is to be square one needs to know what kinds of sensory experience square things produce. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 8) | |
| A reaction: Are any experiences involved in the understanding of squareness? We don't know squareness by a priori intuition (do we?). To grasp squareness if may be necessary to have a variety of experiences of it. Or to grasp that it is primary. |
| 22414 | You don't need to know how a square thing looks or feels to understand squareness [McGinn] |
| Full Idea: To grasp what it is for something to be square it is not constitutively necessary to know how square things look or feel, since what it is to be square does not involve any such relation to experience. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: You could even describe squareness verbally, unlike redness. It seems crucial that almost any sense (such as bat echoes) can communicate primary qualities, but secondary qualities are tied to a sense, and wouldn't exist without it. |
| 22423 | Touch doesn't provide direct experience of primary qualities, because touch feels temperature [McGinn] |
| Full Idea: Bennett's claim that touch provides experience of primary qualities without experience of any secondary qualities strikes me as false, because tactile experience includes felt temperature, which is a dispositional secondary quality. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: [J.Bennett 1971 pp. 90-4] Fair point. What about shape and texture? We experience forces, but the shape is assembled in imagination rather than in experience. So do we meet primary qualities directly in forces, such as acceleration? No secondary quality? |
| 22426 | We can perceive objectively, because primary qualities are not mind-created [McGinn] |
| Full Idea: I hold that experience succeeds in representing the world objectively, since primary quality perceptual content is not contributed by the mind. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: My new example of a direct perception of a primary quality is acceleration in a lift. What would we say to one passenger who denied feeling the acceleration? It took an effort to see that mind contributes to secondary qualities (so make more effort?). |
| 22412 | Lockean secondary qualities (unlike primaries) produce particular sensory experiences [McGinn] |
| Full Idea: In the Lockean tradition, secondary qualities are defined as those whose instantiation in an object consists in a power or disposition of the object to produce sensory experiences in perceivers of a certain phenomenological character. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: Primary qualities are said to lack such dispositions. Not sure about these definitions. Primaries offer no experiences? With these definitions, comparing them would be a category mistake. I take it primaries reflect reality and secondaries do not. |
| 22421 | Could there be a mind which lacked secondary quality perception? [McGinn] |
| Full Idea: Can we form a conception of a type of mind whose representations are free of secondary quality perceptions? | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: Nice question. Minds must have experiences, and there has to be a 'way' or 'mode' for those experiences. A mind which directly grasped the primary quality of sphericity would seem to be visionary rather than sensual or experiential. |
| 22424 | Secondary qualities contain information; their variety would be superfluous otherwise [McGinn] |
| Full Idea: Surely we learn something about an object when we discover its secondary qualities? ...If secondary quality experience were informationally inert, its variety would be something of a puzzle. Why not employ the same medium for all primary informaton? | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: This is important. We can't just focus on the primary qualities, and ignore the secondary. But diverse colours draw attention to information, which can then be translated into neutral data, as in spectroscopic analysis. Locke agrees with this. |
| 22425 | The utility theory says secondary qualities give information useful to human beings [McGinn] |
| Full Idea: Secondary quality perception, according to the utility theory, gives information about the relation between the perceptual object and the perceiver's needs and interests. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: Almost the only example I can think of is whether fruit is ripe or rotten. ...Also 'bad' smells. We recognise aggressive animal noises, but that is not the same as dangerous (e.g. rustling snake). Divine design is behind this theory, I think. |
| 7629 | We see objects 'directly' by representing them [McGinn] |
| Full Idea: My view is that we see objects 'directly' by representing them in visual experience. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], Ch.8 n1) | |
| A reaction: [Quoted by Maund] This rejects both inference in perception and sense-data, while retaining the notion of representation. It is a view which has gained a lot of support. But how can it be direct if it represents? Photographs can't do that. |
| 6081 | Necessity and possibility are big threats to the empiricist view of knowledge [McGinn] |
| Full Idea: It is clear that modality is a prima-facie threat to the usual kind of naturalistic-causal-empiricist theory of knowledge. | |
| From: Colin McGinn (Logical Properties [2000], Ch.4) | |
| A reaction: This is why modern empiricists spend of a lot of energy on trying to analyse counterfactuals and laws of nature. Rationalists are much happier to assert necessities a priori, but then they often don't have much basis for their claims. |
| 6071 | Scepticism about reality is possible because existence isn't part of appearances [McGinn] |
| Full Idea: Scepticism about the external world is possible because you can never build existence into the appearances, so it must always be inferred or assumed. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: When McGinn's claim that existence is a very universal property begins to produce interesting observations like this, I think we should take it very seriously. |
| 4691 | If all mental life were conscious, we would be unable to see things, or to process speech [McGinn] |
| Full Idea: If there were nothing more to our mind than our conscious awareness, then we would be unable to see anything or to process speech. | |
| From: Colin McGinn (The Making of a Philosopher [2002], Ch. 6) | |
| A reaction: A vital point. Traditional dualism has left us a simplistic exaggeration of the role of consciousness, and the misapprehension that most of what we do is conscious - which it clearly isn't, once you think about it. |
| 2539 | Mental modules for language, social, action, theory, space, emotion [McGinn] |
| Full Idea: The prevailing view in cognitive psychology is that the mind consists of separate faculties, each with a certain cognitive task: linguistic, social, practical, theoretical, abstract, spatial and emotional. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.40) | |
| A reaction: 'Faculties' are not quite the same as 'modules', and this list mostly involves more higher-order activities than a modules list (e.g. Idea 2495). The idea that emotion is a 'faculty' sounds old-fashioned. |
| 2545 | Free will is mental causation in action [McGinn] |
| Full Idea: Free will is mental causation in action. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.167) |
| 2543 | Brains aren't made of anything special, suggesting panpsychism [McGinn] |
| Full Idea: All matter must contain the potential to underlie consciousness, since there is nothing special about the matter that composes brain tissue. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.100) | |
| A reaction: This seems to me one of the most basic assumptions which we should all make about the mind. The mind is made of the brain, and the brain is made of food. However, there must be something 'special' about the brain. |
| 3192 | Basic logic can be done by syntax, with no semantics [Gödel, by Rey] |
| Full Idea: Gödel in his completeness theorem for first-order logic showed that a certain set of syntactically specifiable rules was adequate to capture all first-order valid arguments. No semantics (e.g. reference, truth, validity) was necessary. | |
| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Georges Rey - Contemporary Philosophy of Mind 8.2 | |
| A reaction: This implies that a logic machine is possible, but we shouldn't raise our hopes for proper rationality. Validity can be shown for purely algebraic arguments, but rationality requires truth as well as validity, and that needs propositions and semantics. |
| 7388 | McGinn invites surrender, by saying it is hopeless trying to imagine conscious machines [Dennett on McGinn] |
| Full Idea: McGinn invites his readers to join him in surrender: It's just impossible to imagine how software could make a conscious robot. Don't even try, he says. Other philosophical experiments (involving China) "work" by dissuading readers from imagining. | |
| From: comment on Colin McGinn (The Problem of Consciousness [1991]) by Daniel C. Dennett - Consciousness Explained 14.1 | |
| A reaction: I agree with Dennett. If you don't try to imagine how robots might do it, you are also denied the right to try to imagine how brains might manage it. Admittedly this is hard, but good imagination needs study, effort, discussion, time, information... |
| 2540 | Examining mind sees no brain; examining brain sees no mind [McGinn] |
| Full Idea: You can look into your mind until you burst and not discover neurons and synapses, and you can stare at someone's brain from dawn till dusk and not perceive the consciousness that is so apparent to the person whose brain it is. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.47) | |
| A reaction: This is a striking symmetry of ignorance, though hardly enough to justify McGinn's pessimism about understanding the mind. 'When you are in the grass you can't see the whole of England; if you can see the whole of England, you won't see the grass'. |
| 3185 | Multiple realisability rules out hidden essences and experts as the source of water- and gold-concepts [McGinn] |
| Full Idea: The multiple realisability emphasised by functionalists rules out the hidden essences (and the 'deferential' move in semantics) that one finds in the cases, for example, of "water" and "gold" emphasised by Kripke and Putnam. | |
| From: Colin McGinn (The Problem of Consciousness [1991], p.132) | |
| A reaction: Presumably if they are 'hidden', then the people to whom we 'defer' for our concepts can't actually know about the essences we are supposed to be discussing. You can mean essences without knowing them. Cf. Loch Ness Monster. |
| 22420 | The indexical perspective is subjective, incorrigible and constant [McGinn] |
| Full Idea: I attribute three properties to the indexical perspective: it is subjective, incorrigible, and constant. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 5) | |
| A reaction: That is as good an idea as any for summarising the view (associated with John Perry) that the indexical perspective is an indispensable feature of reality. For a good attack on this, which I favour, see Cappelen and Dever. |
| 18410 | Indexical thought is in relation to my self-consciousness [McGinn] |
| Full Idea: Very roughly, we can say that to think of something indexically is to think of it in relation to me, as I am presented to myself in self-consciousness. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: So it is characterised relationally, which doesn't mean it has a distinctive intrinsic character. If I'm lost, and I overhear someone say 'Peter is in Hazlemere', I get the same relational information (in a different mode) without the indexicality. |
| 22417 | Indexicals do not figure in theories of physics, because they are not explanatory causes [McGinn] |
| Full Idea: Indexicals are like secondary qualities in not figuring in causal explanations of the interactions of objects: physics omits them not because they are relative and egocentric, but because they do not constitute explanatory predicates of a causal theory. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: They are outside explanatory physics, but not outside explanation. The object moved because a force acted on it; or the object moved because I wanted it moved. |
| 18402 | Indexical concepts are indispensable, as we need them for the power to act [McGinn] |
| Full Idea: The present suggestion is that indexical concepts are ineliminable because without them agency would be impossible: when I imagine myself divested of indexical thoughts employing only centreless mental representations, I am deprived of the power to act. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: A nice clear statement of the view developed by Perry and Lewis. I agree with Cappelen and Dever that it is entirely wrong, and that indexical thought is entirely eliminable, and nothing special. |
| 4690 | If meaning is speaker's intentions, it can be reduced to propositional attitudes, and philosophy of mind [McGinn] |
| Full Idea: The importance of Grice's analysis of speaker meaning is that it offers the prospect of analysing the whole phenomenon of linguistic meaning in terms of propositional attitudes… thus turning semantics into a department of the philosophy of mind. | |
| From: Colin McGinn (The Making of a Philosopher [2002], Ch. 5) | |
| A reaction: Although meaning being truth conditions is the most cited theory, the reduction of semantics to an aspect of mind also seems almost orthodox now. But how do the symbols 'represent' the attitudes? |
| 6077 | Semantics should not be based on set-membership, but on instantiation of properties in objects [McGinn] |
| Full Idea: Semantics should not employ the relationship of set-membership between objects and extensions, but rather the relation of instantiation between objects and properties. | |
| From: Colin McGinn (Logical Properties [2000], Ch.3) | |
| A reaction: At least this means that philosophers won't be required to read fat books on set theory, but they will have to think very carefully about 'instantiation'. A good start is the ideas on 'Partaking' of Platonic Forms in this database (in 'Universals'). |
| 2547 | There is information if there are symbols which refer, and which can combine into a truth or falsehood [McGinn] |
| Full Idea: There is information in a system if there are symbols in it that refer to things and that together form strings that can be true or false. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.225) | |
| A reaction: We can also directly apprehend information by perception. Are facts identical with correct information? Can a universal generalisation be information? |
| 6074 | Clearly predicates have extensions (applicable objects), but are the extensions part of their meaning? [McGinn] |
| Full Idea: We are taught that predicates have extensions - the class of objects of which the predicate is true - which seems hard to deny; but a stronger claim is also made - that extensions are semantically relevant features of predicates. | |
| From: Colin McGinn (Logical Properties [2000], Ch.3) | |
| A reaction: He cites Quine as a spokesman for this view. McGinn is going on to challenge it, by defending universals. It seems to fit in with other externalist theories of concepts and meanings, none of which seems very appealing to me. |
| 22418 | I can know indexical truths a priori, unlike their non-indexical paraphrases [McGinn] |
| Full Idea: I know the truth of the sentence 'I am here now' a priori, but I do not know a priori 'McGinn is in London on 15th Nov 1981'. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 3) | |
| A reaction: I'm not convinced that I can grasp the concepts of 'here' and 'now' (i.e. space and time) by purely a priori means. But he certainly shows that you can't glibly dismiss indexicals by paraphrasing them in that way. |
| 7894 | Hate is conquered by love [Anon (Dham)] |
| Full Idea: Hate is not conquered by hate: hate is conquered by love. This is the law eternal. | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §1.5) | |
| A reaction: [N.B. This thought was not invented by Jesus] The challenge to this view might be the tit-for-tat strategy of game theory, which says that hate is actually conquered by a combination of hate and love, judiciously applied. |
| 7899 | Even divine pleasure will not satisfy the wise, as it is insatiable, and leads to pain [Anon (Dham)] |
| Full Idea: Since a shower of gold coins could not satisfy craving desires and the end of all pleasure is pain, how could a wise man find satisfaction even in the pleasures of the gods? | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §14.186) | |
| A reaction: I'm never sure how so many ancient thinkers arrived at this implausible view. They seem to think that no one knows when to stop, and that every drink leads to hangover. What is actually wrong with moderate sensible pleasure? |
| 7896 | The foolish gradually fill with evil, like a slowly-filled water-jar [Anon (Dham)] |
| Full Idea: The falling of drops of water will in time fill a water-jar. Even so the foolish man becomes full of evil, although he gather it little by little. | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §9.121) | |
| A reaction: This coincides closely with Aristotle's view of moral education. Maybe a wise man can maintain one small vice. Not all slopes are slippery. |
| 7897 | The wise gradually fill with good, like a slowly-filled water-jar [Anon (Dham)] |
| Full Idea: The falling of drops of water will in time fill a water-jar. Even so the wise man becomes full of good, although he gather it little by little. | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §9.122) | |
| A reaction: Again, this is like Aristotle's proposal of how to educate people in virtue. In my experience, there is no guarantee that small acts of politeness and charity will eventually guarantee goodness of character. Thought is also needed. |
| 7895 | Don't befriend fools; either find superior friends, or travel alone [Anon (Dham)] |
| Full Idea: If on the great journey of life a man cannot find one who is better or at least as good as himself, let him joyfully travel alone: a fool cannot help him on his journey. | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §5.61) | |
| A reaction: This is a slightly disturbing aspect of Buddhism, possibly leading to contradiction. It urges friendship and love, but the finest people will have virtually no friends, and solitude is presented as a finer state than friendship. |
| 2542 | Causation in the material world is energy-transfer, of motion, electricity or gravity [McGinn] |
| Full Idea: Causation in the material world works by energy transfer of some sort: transfer of motion, of electrical energy, of gravitational force. | |
| From: Colin McGinn (The Mysterious Flame [1999], p.92) |
| 6072 | If Satan is the most imperfect conceivable being, he must have non-existence [McGinn] |
| Full Idea: Satan cannot exist because he is the most imperfect conceivable being, and existence is one of the perfections. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: The logic of this seems right to me. Presumably the theologians would hastily deny this as a definition of Satan; he must have some positive qualities (like power) in order to enact his supreme moral imperfections. NIce, though. |
| 6073 | I think the fault of the Ontological Argument is taking the original idea to be well-defined [McGinn] |
| Full Idea: My own suspicion about the Ontological Argument is that the fault lies in taking notions like 'the most perfect, impressive and powerful being conceivable' to be well-defined. | |
| From: Colin McGinn (Logical Properties [2000], Ch.2) | |
| A reaction: I'm tempted to put it more strongly: the single greatest challenge for the theist with intellectual integrity is to give a clear and coherent definition of God. There must be no internal contradictions, and it must be within the bounds of possibility. |
| 7900 | Speak the truth, yield not to anger, give what you can to him who asks [Anon (Dham)] |
| Full Idea: Speak the truth, yield not to anger, give what you can to him who asks: these three steps lead you to the gods | |
| From: Anon (Dham) (The DhammaPada [c.250 BCE], §17.224) | |
| A reaction: I don't recall either the Old or New Testament, or the Koran, placing great emphasis on speaking the truth. The injunction to give is not so simple. Give to greedy children, to alcoholics, to criminals, to the rich, to fools, to yourself? |