26 ideas
| 21918 | Sufficient Reason can't be proved, because all proof presupposes it [Schopenhauer, by Lewis,PB] |
| Full Idea: Schopenhauer said the principle of sufficient reason is not susceptible to proof for the simple reason that it is presupposed in any argument or proof. | |
| From: report of Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813], §14 p.32-3) by Peter B. Lewis - Schopenhauer 3 | |
| A reaction: I would have thought it might be disproved by a counterexample, such as the Gödel sentence of his incompleteness proof, or quantum effects which seem to elude causation. Personally I believe the principle, which I see as the first axiom of philosophy. |
| 17884 | Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner] |
| Full Idea: There are many coherent stopping points in the hierarchy of increasingly strong mathematical systems, starting with strict finitism, and moving up through predicativism to the higher reaches of set theory. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], Intro) |
| 17893 | 'Reflection principles' say the whole truth about sets can't be captured [Koellner] |
| Full Idea: Roughly speaking, 'reflection principles' assert that anything true in V [the set hierarchy] falls short of characterising V in that it is true within some earlier level. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 2.1) |
| 17894 | We have no argument to show a statement is absolutely undecidable [Koellner] |
| Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3) |
| 17890 | There are at least eleven types of large cardinal, of increasing logical strength [Koellner] |
| Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable). | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4) | |
| A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway] |
| 17887 | PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner] |
| Full Idea: To the extent that we are justified in accepting Peano Arithmetic we are justified in accepting its consistency, and so we know how to expand the axiom system so as to overcome the limitation [of Gödel's Second Theorem]. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.1) | |
| A reaction: Each expansion brings a limitation, but then you can expand again. |
| 17891 | Arithmetical undecidability is always settled at the next stage up [Koellner] |
| Full Idea: The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4) |
| 21920 | No need for a priori categories, since sufficient reason shows the interrelations [Schopenhauer, by Lewis,PB] |
| Full Idea: Schopenhauer dispenses with Kant's a priori categories, since all interrelations between representations are given through the principle of sufficient reason. | |
| From: report of Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813]) by Peter B. Lewis - Schopenhauer 3 | |
| A reaction: I'm not sure how Schopenhauer manages this move. Is it the stoic idea that reality has a logical structure, which can be inferred? Sounds good to me. Further investigation required. |
| 21362 | Necessity is physical, logical, mathematical or moral [Schopenhauer, by Janaway] |
| Full Idea: For Schopenauer there are physical necessity, logical necessity, mathematical necessity and moral necessity. | |
| From: report of Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813]) by Christopher Janaway - Schopenhauer 2 'Fourfold' | |
| A reaction: These derive from four modes of explanation, by causes, by grounding in truths or facts, by mathematical reality, and by motives. Not clear why mathematics gets its own necessity. I like metaphysics derived from explanations, though. Necessity makers. |
| 21361 | For Schopenhauer, material things would not exist without the mind [Schopenhauer, by Janaway] |
| Full Idea: Schopenhauer is not a realist about material things, but an idealist: that is, material things would not exist, for him, without the mind. | |
| From: report of Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813]) by Christopher Janaway - Schopenhauer 2 'Fourfold' | |
| A reaction: Janaway places his views as close to Kant's, but it is not clear that Kant would agree that no mind means no world. Did Schopenhauer believe in the noumenon? |
| 21919 | Object for a subject and representation are the same thing [Schopenhauer] |
| Full Idea: To be object for a subject and to be representation is to be one and the same thing. All representations are objects for a subject, all objects for a subject are representations. | |
| From: Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813], §16 p.41-2), quoted by Peter B. Lewis - Schopenhauer 3 | |
| A reaction: This is pure idealism in early Schopenhauer, derived from Kant. Are being 'an object for a subject' and being an object 'in itself' two different things? Compare Idea 21914, written later. I think Nietzsche's 'perspective' representations helps here. |
| 21917 | The four explanations: objects by causes, concepts by ground, maths by spacetime, ethics by motive [Schopenhauer, by Lewis,PB] |
| Full Idea: There are four forms of explanation, depending on their topic. Causes explain objects. Grounding explains concepts, Points and moments explain mathematics. Motives explain ethics. | |
| From: report of Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813], §43 p.214) by Peter B. Lewis - Schopenhauer 3 | |
| A reaction: [My compression of Lewis's summary. I'm particularly pleased with this. I have done Schopenhauer a huge favour, should anyone ever visit this website]. The quirky account of mathematics derives from Kant. I greatly admire this whole idea. |
| 4608 | Minds are hard-wired, or trial-and-error, or experimental, or full self-aware [Dennett, by Heil] |
| Full Idea: Dennett identifies a hierarchy of minds running from 'Darwinian' (hard-wired solutions to problems), to 'Skinnerian' (trial-and-error), to 'Popperian' (anticipating possible experience), to 'Gregorian' (self-conscious representation, probably linguistic). | |
| From: report of Daniel C. Dennett (Kinds of Minds [1996]) by John Heil - Philosophy of Mind Ch.5 | |
| A reaction: Interesting. The concept of an experiment seems a major step (assessing reality against an internal map), and the ability to think about one's own thoughts certainly strikes me as the mark of a top level mind. Maybe that is the importance of language. |
| 4880 | Sentience comes in grades from robotic to super-human; we only draw a line for moral reasons [Dennett] |
| Full Idea: 'Sentience' comes in every imaginable grade or intensity, from the simplest and most 'robotic', to the most exquisitely sensitive, hyper-reactive 'human'. We have to draw a line for moral policy, but it is unlikely we will ever discover a threshold. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.4) | |
| A reaction: This is the only plausible view, if you take the theory of evolution seriously. We can even observe low-grade marginal sentience in our own minds, and then shoot up the scale when we focus our minds properly on an object. |
| 4873 | What is it like to notice an uncomfortable position when you are asleep? [Dennett] |
| Full Idea: What is it like to notice, while sound asleep, that your left arm has become twisted into a position in which it is putting undue strain on your left shoulder? Like nothing. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.1) | |
| A reaction: A nice question, and all part of Dennett's accurate campaign to show that consciousness is not an all-or-nothing thing. As when we are barely aware of driving, innumerable things happen in the shadowy corners of thought. |
| 4881 | Being a person must involve having second-order beliefs and desires (about beliefs and desires) [Dennett] |
| Full Idea: An important step towards becoming a person is the step up from a first-order intentional system to a second-order system (which has beliefs and desires about beliefs and desires). | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.5) | |
| A reaction: Call it 'meta-thought'. I agree. Dennett thinks language is crucial to this, but the hallmark of intelligence and full-blown personhood is meta- and meta-meta-thought. Maybe the development of irony is a step up the evolutionary scale. Sarcasm is GOOD. |
| 4875 | We descend from robots, and our intentionality is composed of billions of crude intentional systems [Dennett] |
| Full Idea: We are descended from robots, and composed of robots, and all the intentionality we enjoy is derived from the more fundamental intentionality of billions of crude intentional systems. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.2) | |
| A reaction: A more grand view of intentionality (such as Searle's) seems more attractive than this, but the crucial fact about Dennett is that he takes the implications of evolution much more seriously than other philosophers. He's probably right. |
| 4879 | There is no more anger in adrenaline than silliness in a bottle of whiskey [Dennett] |
| Full Idea: There is no more fear or anger in adrenaline than there is silliness in a bottle of whiskey. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.3) | |
| A reaction: Not exactly an argument, but a nice rhetorical point against absurd claims about identity and reduction and elimination. We may say that there is no fear without adrenaline, and no adrenaline in a live brain without fear. |
| 4876 | Maybe there is a minimum brain speed for supporting a mind [Dennett] |
| Full Idea: Perhaps there is a minimum speed for a mind, rather like the minimum escape velocity required to overcome gravity and leave the planet. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.3) | |
| A reaction: Dennett rejects this speculation, but he didn't stop to imagine what it would be LIKE if your brain slowed down, and he never considers Edelman's view that mind is a process. Put the two together… |
| 4878 | The materials for a mind only matter because of speed, and a need for transducers and effectors [Dennett] |
| Full Idea: I think there are only two good reasons why, when you make a mind, the materials matter: speed, and the ubiquity of transducers and effectors throughout the nervous system. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.3) | |
| A reaction: This sounds roughly right, because it gives you something between multiple realisability (minds made of cans and string), and type-type identity (minds ARE a particular material). Call it 'biological functionalism'? |
| 4874 | The predecessor and rival of the language of thought hypothesis is the picture theory of ideas [Dennett] |
| Full Idea: The ancestor and chief rival of the language-of-thought hypothesis is the picture theory of ideas - that thoughts are about what they are about because they resemble their objects. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.2) | |
| A reaction: When you place them side by side, neither seems quite right. How can a mental state resemble an object, and how can an inner language inherently capture the features of an object? Maybe we lack the words for the correct theory. |
| 21921 | Concepts are abstracted from perceptions [Schopenhauer, by Lewis,PB] |
| Full Idea: For Schopenhauer concepts are abstractions from perception, what he calls 'representations of representations', and are linked to the creation of language. | |
| From: report of Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813]) by Peter B. Lewis - Schopenhauer 3 | |
| A reaction: This is a traditional view which dates back to Aristotle, and which I personally think is entirely correct. These days I am in minority on that. This idea means that (contrary to Kant) perception is not conceptual. |
| 4882 | Concepts are things we (unlike dogs) can think about, because we have language [Dennett] |
| Full Idea: A dog cannot consider its concepts. Concepts are not things in a dog's world in the way that cats are. Concepts are things in our world, because we have language. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.6) | |
| A reaction: Dogs must have concepts, though, or much of their behaviour (like desperation to go for a walk, or to eat) is baffling. This is as good a proposal as I have ever encountered for the value of language. Meta-thought is a huge evolutionary advantage. |
| 21363 | Motivation is causality seen from within [Schopenhauer] |
| Full Idea: Motivation is causality seen from within. | |
| From: Arthur Schopenhauer (Fourfold Root of Princ of Sufficient Reason [1813], p.214), quoted by Christopher Janaway - Schopenhauer 2 'Fourfold' | |
| A reaction: This is more illuminating about causation than about motivation, since we can be motivated without actually doing anything. |
| 4872 | Most people see an abortion differently if the foetus lacks a brain [Dennett] |
| Full Idea: If a fetus that is being considered for abortion is known to be anencephalic (lacking a brain), this dramatically changes the issue for most people, though not for all. | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.1) | |
| A reaction: A very effective point, as it is hard to see what grounds could be given for not aborting in this case. But the brain then clearly becomes the focus of why abortion is often rejected by many people. |
| 4877 | Maybe plants are very slow (and sentient) animals, overlooked because we are faster? [Dennett] |
| Full Idea: Might plants just be 'very slow animals', enjoying sentience that has been overlooked by us because of our human timescale chauvinism? | |
| From: Daniel C. Dennett (Kinds of Minds [1996], Ch.3) | |
| A reaction: Delightful thought, arising from pondering the significance of the speed of operation of the brain. I think it is false, because I think high speed is essential to mind, and Dennett seems not to. |