43 ideas
| 5333 | Philosophy needs wisdom about who we are, as well as how we ought to be [Flanagan] |
| Full Idea: Any good philosophy will need to offer wisdom about who we are as well as about how we ought to be. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 14) | |
| A reaction: This sop should be accepted gratefully by fans of bioethics, who seem inclined to think that describing 'how we are' is all that needs to be said. Maybe the key wisdom lies in the relationship between the 'is' and the 'ought' of human nature. |
| 22026 | Philosophy is homesickness - the urge to be at home everywhere [Novalis] |
| Full Idea: Philosophy is actually homesickness - the urge to be everywhere at home. | |
| From: Novalis (General Draft [1799], 45) | |
| A reaction: The idea of home [heimat] is powerful in German culture. The point of romanticism was seen as largely concerning restless souls like Byron and his heroes, who do not feel at home. Hence ironic detachment. |
| 5334 | We resist science partly because it can't provide ethical wisdom [Flanagan] |
| Full Idea: The inability of science to provide ethical wisdom is partly responsible for our resistance to the scientific image. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 14) | |
| A reaction: This seems right. A.J. Ayer, for example, declared "I believe in science", and his account of ethics was vacuously nihilistic. A description of the mechanisms of moral life is not the same as ethical wisdom. |
| 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| From: report of Kurt Gödel (On Formally Undecidable Propositions [1931]) by Willard Quine - Forward to Gödel's Unpublished | |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. |
| 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. |
| 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. |
| 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. |
| 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 |
| 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. |
| 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. |
| 5340 | Explanation does not entail prediction [Flanagan] |
| Full Idea: Explanation does not entail prediction. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 73n) | |
| A reaction: Presumably the inverse of this is also true, as we might be able to predict through pure induction, without knowing why something happened. We predict that smoking is likely to cause cancer. Complex things might be explicable but unpredictable. |
| 5346 | In the 17th century a collisionlike view of causation made mental causation implausible [Flanagan] |
| Full Idea: In the seventeenth century the dominant idea that causation is collisionlike made mental causation almost impossible to envision. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.136) | |
| A reaction: Interesting. This makes Descartes' interaction theory look rather bold, and Leibniz's and Malebranche's rejection of it understandable. Personally I still think of causation as collisionlike, except that the collisions are of very very tiny objects. |
| 5341 | Only you can have your subjective experiences because only you are hooked up to your nervous system [Flanagan] |
| Full Idea: It is easy to explain why certain brain events are uniquely experienced by you subjectively: only you are properly hooked up to your own nervous system to have your own experiences. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 87) | |
| A reaction: This is in reply to Nagel's oft quoted claim that mind can only be understood as "what it is like to be" that mind. I agree with Flanagan, and it is nice illustration of how philosophers can confuse themselves with high-sounding questions. |
| 19591 | Desire for perfection is an illness, if it turns against what is imperfect [Novalis] |
| Full Idea: An absolute drive toward perfection and completeness is an illness, as soon as it shows itself to be destructive and averse toward the imperfect, the incomplete. | |
| From: Novalis (General Draft [1799], 33) | |
| A reaction: Deep and true! Novalis seems to be a particularist - hanging on to the fine detail of life, rather than being immersed in the theory. These are the philosophers who also turn to literature. |
| 5351 | We only have a sense of our self as continuous, not as exactly the same [Flanagan] |
| Full Idea: We only have a sense of our self as continuous, but not as exactly the same. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.178) | |
| A reaction: Russell said this too, and it seems to me to be right. Personal identity is far too imprecise for me to assert that I remember my ten-year-old self as being identical to me now. Only physical objects like teddy bears can pass that test. |
| 5353 | The self is an abstraction which magnifies important aspects of autobiography [Flanagan] |
| Full Idea: The self is an abstraction from the story of a person's life that isolates and magnifies the experiences, traits and aspirations that are assigned importance. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.240) | |
| A reaction: Personally I am inclined to see personal identity as the central controller of brain activity, the aspect of the biological machine which keeps all the mental events focused on what matters, which is health, safety and happiness. |
| 5354 | We are not born with a self; we develop a self through living [Flanagan] |
| Full Idea: It is a bad mistake to think we are born with a self; the self develops, and acquiring it requires living in the world. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.260) | |
| A reaction: I think this is wrong. He is mistaking a complex cultural concept of the self as the subject for autobiography etc. for the basic biological self which even small animals must have if their brains are to serve any useful purpose in their lives. |
| 5349 | For Buddhists a fixed self is a morally dangerous illusion [Flanagan] |
| Full Idea: According to Buddhism, the idea of a permanent, constant self is an illusion, and a morally dangerous one. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.161) | |
| A reaction: We are familiar with the idea that it might be an illusion, but I am unconvinced by 'morally dangerous'. If you drop both free will and personal identity, I can't see any sort of focus for moral life left, but I am willing to be convinced. |
| 5338 | Normal free will claims control of what I do, but a stronger view claims control of thought and feeling [Flanagan] |
| Full Idea: The standard view of free will is that I have something like complete control over what I do. A stronger view (not widely held) is that I also have complete control over what I think and what I feel. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 60n) | |
| A reaction: To claim free control of feelings looks optimistic, but it does look as if we can decide to think about something, such as a philosophical problem. Deciding what to say comes somewhere between thought and action. |
| 5344 | Free will is held to give us a whole list of desirable capacities for living [Flanagan] |
| Full Idea: Free will is said to give us self-control, self-expression, individuality, reasons-sensitivity, rational deliberation, rational accountability, moral accountability, the capacity to do otherwise, unpredictability, and political freedom. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.104) | |
| A reaction: Nice list. His obvious challenge is to either say we can live happily without some of these things, or else show how we can have them without 'free will'. Personally I agree with Flanagan that we meet the challenge. |
| 5332 | People believe they have free will that circumvents natural law, but only an incorporeal mind could do this [Flanagan] |
| Full Idea: Most people believe we have free will, and that this consists in the ability to circumvent natural law. The trouble is that the only device ever philosophically invented that can do this sort of job is an incorporeal soul or mind. | |
| From: Owen Flanagan (The Problem of the Soul [2002], Pref) | |
| A reaction: I think this is exactly right. We currently have a western world full of people who have rejected dualism, but still cling on to free will, because they think morality depends on it. I think morality depends on personal identity, but not on free will. |
| 5345 | We only think of ourselves as having free will because we first thought of God that way [Flanagan] |
| Full Idea: It is unimaginable to me that, despite the feeling that we control what we do, such a strong conception of ourselves as unmoved movers would have been added to our self-image unless we had first conceived of God along these lines. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.107) | |
| A reaction: I think this is right, though there are signs in fifth century Greece of contradictory evidence. The 'unmoved mover' seems unformulated before Plato's 'Laws' (idea 1423), but there is an implied belief in free will a hundred years earlier. |
| 5343 | People largely came to believe in dualism because it made human agents free [Flanagan] |
| Full Idea: I would say that that my consciousness doesn't seem either physical or non-physical, ..but the belief that the mind is non-physical partly took hold because that fits well with thinking of human agents as free. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.102) | |
| A reaction: I think this is right. I personally think there is no such thing as free will, and that belief in it has been the single greatest delusion amongst philosophers (and others) for the last two thousand years. Dualism has now gone, and free will is next. |
| 5347 | Behaviourism notoriously has nothing to say about mental causation [Flanagan] |
| Full Idea: Behaviourism was notorious in its heyday for having nothing to say about mental causation. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.141) | |
| A reaction: This is a bit unfair, as Ryle (idea 2622, following Spinoza, 4862) was one of the first to point out the paradox of 'double causation'. You have to be a mentalist to worry about mental causation, and eliminativists aren't bothered. |
| 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. |
| 5339 | Cars and bodies obey principles of causation, without us knowing any 'strict laws' about them [Flanagan] |
| Full Idea: Although everyone thinks cars and bodies obey the principles of causation, no one thinks it a deficiency that we don't know strict laws of automechanics or anatomy. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 65) | |
| A reaction: This attacks Davidson's claim that there are no strict psycho-physical laws, and I agree with Flanagan. Huge dreams of free will and human dignity are being pinned on the flimsy point that we have no strict laws here. But brains are very complicated. |
| 5342 | Physicalism doesn't deny that the essence of an experience is more than its neural realiser [Flanagan] |
| Full Idea: One may be committed to the truth of physicalism without being committed to the claim that the essence of an experience is captured fully by a description of its neural realiser. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 90) | |
| A reaction: This is a reply to the Leibniz Mill question (idea 2109) about what is missing from a materialist view. Flanagan's point is that just as the essence of a panorama is the view from the hill, so the essence of consciousness requires you to be that brain. |
| 5335 | Emotions are usually very apt, rather than being non-rational and fickle [Flanagan] |
| Full Idea: One can question the idea that emotions are non-rational, fickle and flighty; on the contrary, emotions normally seem to be very apt. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 16) | |
| A reaction: This is the modern view of emotion which is emerging from neuroscience, which is greatly superior to traditional views, apart from Aristotle, who felt that wisdom and virtue arose precisely when emotions were apt for the situation. |
| 5348 | Intellectualism admires the 'principled actor', non-intellectualism admires the 'good character' [Flanagan] |
| Full Idea: There are two main pictures of the good person: there is the 'good character', and there is the 'principled actor'. ..The first picture is non-intellectualist, and the second is intellectualist. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.145) | |
| A reaction: The second ideal elevates the principle itself above the actor who carries it out. Presumably consistency is a virtue, so a good character will at least pay some attention to principles. A good magistrate comes out the same in both views. |
| 5355 | Cognitivists think morals are discovered by reason [Flanagan] |
| Full Idea: Cognitivists think morals are discovered by reason. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.301n) | |
| A reaction: I take cognitivism to be (strictly) the view that morals are knowable in principle. Our intellects might not be up to the task (and so we might have to ask the gods what is right). There is also the possibility that morals might be known by intuition. |
| 5336 | Ethics is the science of the conditions that lead to human flourishing [Flanagan] |
| Full Idea: Ethics is the normative science that studies the objective conditions that lead to flourishing of persons. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p. 17) | |
| A reaction: This is a nice slogan for the virtue theory account of the nature of ethics. I think it is the view with which I agree. I am intrigued that he has smuggled the word 'science' in, which is a nice challenge to conventional views of science. |
| 5350 | The Hindu doctrine of reincarnation only appeared in the eighth century CE [Flanagan] |
| Full Idea: The doctrine of a cycle of rebirths and reincarnations that are normally required before one achieve nirvana was only proposed in the eighth century CE, and then spread like wildfire among Hindus and, to a lesser extent, among Buddhists. | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.166n) | |
| A reaction: Intriguing. Plato had proposed it in the fourth century BCE. Presumably Hindus had always been dualists, and then suddenly saw and exciting possibility that followed from it. The doctrine strikes me as (to put it mildly) implausible. |
| 5352 | The idea of the soul gets some support from the scientific belief in essential 'natural kinds' [Flanagan] |
| Full Idea: The idea of the soul could be easily trashed if science does not countenance essences, but science does countenance essences in the form of what are known as 'natural kinds' (such as water, salt and gold). | |
| From: Owen Flanagan (The Problem of the Soul [2002], p.181) | |
| A reaction: The existence of any essences at all does indeed make the existence of a soul naturally possible, but scientific natural kinds are usually postulated on a basis of chemical stability. Animals, for example, are no longer usually classified that way. |