26 ideas
| 18806 | Frege thought traditional categories had psychological and linguistic impurities [Frege, by Rumfitt] |
| Full Idea: Frege rejected the traditional categories as importing psychological and linguistic impurities into logic. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by Ian Rumfitt - The Boundary Stones of Thought 1.2 | |
| A reaction: Resisting such impurities is the main motivation for making logic entirely symbolic, but it doesn't follow that the traditional categories have to be dropped. |
| 8490 | First-level functions have objects as arguments; second-level functions take functions as arguments [Frege] |
| Full Idea: Just as functions are fundamentally different from objects, so also functions whose arguments are and must be functions are fundamentally different from functions whose arguments are objects. The latter are first-level, the former second-level, functions. | |
| From: Gottlob Frege (Function and Concept [1891], p.38) | |
| A reaction: In 1884 he called it 'second-order'. This is the standard distinction between first- and second-order logic. The first quantifies over objects, the second over intensional entities such as properties and propositions. |
| 8492 | Relations are functions with two arguments [Frege] |
| Full Idea: Functions of one argument are concepts; functions of two arguments are relations. | |
| From: Gottlob Frege (Function and Concept [1891], p.39) | |
| A reaction: Nowadays we would say 'two or more'. Another interesting move in the aim of analytic philosophy to reduce the puzzling features of the world to mathematical logic. There is, of course, rather more to some relations than being two-argument functions. |
| 8487 | Arithmetic is a development of logic, so arithmetical symbolism must expand into logical symbolism [Frege] |
| Full Idea: I am of the opinion that arithmetic is a further development of logic, which leads to the requirement that the symbolic language of arithmetic must be expanded into a logical symbolism. | |
| From: Gottlob Frege (Function and Concept [1891], p.30) | |
| A reaction: This may the the one key idea at the heart of modern analytic philosophy (even though logicism may be a total mistake!). Logic and arithmetical foundations become the master of ontology, instead of the servant. The jury is out on the whole enterprise. |
| 18899 | Frege takes the existence of horses to be part of their concept [Frege, by Sommers] |
| Full Idea: Frege regarded the existence of horses as a property of the concept 'horse'. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by Fred Sommers - Intellectual Autobiography 'Realism' |
| 4028 | Frege allows either too few properties (as extensions) or too many (as predicates) [Mellor/Oliver on Frege] |
| Full Idea: Frege's theory of properties (which he calls 'concepts') yields too few properties, by identifying coextensive properties, and also too many, by letting every predicate express a property. | |
| From: comment on Gottlob Frege (Function and Concept [1891]) by DH Mellor / A Oliver - Introduction to 'Properties' §2 | |
| A reaction: Seems right; one extension may have two properties (have heart/kidneys), two predicates might express the same property. 'Cutting nature at the joints' covers properties as well as objects. |
| 8489 | The concept 'object' is too simple for analysis; unlike a function, it is an expression with no empty place [Frege] |
| Full Idea: I regard a regular definition of 'object' as impossible, since it is too simple to admit of logical analysis. Briefly: an object is anything that is not a function, so that an expression for it does not contain any empty place. | |
| From: Gottlob Frege (Function and Concept [1891], p.32) | |
| A reaction: Here is the core of the programme for deriving our ontology from our logic and language, followed through by Russell and Quine. Once we extend objects beyond the physical, it becomes incredibly hard to individuate them. |
| 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. |
| 9947 | Concepts are the ontological counterparts of predicative expressions [Frege, by George/Velleman] |
| Full Idea: Concepts, for Frege, are the ontological counterparts of predicative expressions. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.2 | |
| A reaction: That sounds awfully like what many philosophers call 'universals'. Frege, as a platonist (at least about numbers), I would take to be in sympathy with that. At least we can say that concepts seem to be properties. |
| 10319 | An assertion about the concept 'horse' must indirectly speak of an object [Frege, by Hale] |
| Full Idea: Frege had a notorious difficulty over the concept 'horse', when he suggests that if we wish to assert something about a concept, we are obliged to proceed indirectly by speaking of an object that represents it. | |
| From: report of Gottlob Frege (Function and Concept [1891], Ch.2.II) by Bob Hale - Abstract Objects | |
| A reaction: This sounds like the thin end of a wedge. The great champion of objects is forced to accept them here as a façon de parler, when elsewhere they have ontological status. |
| 8488 | A concept is a function whose value is always a truth-value [Frege] |
| Full Idea: A concept in logic is closely connected with what we call a function. Indeed, we may say at once: a concept is a function whose value is always a truth-value. ..I give the name 'function' to what is meant by the 'unsaturated' part. | |
| From: Gottlob Frege (Function and Concept [1891], p.30) | |
| A reaction: So a function becomes a concept when the variable takes a value. Problems arise when the value is vague, or the truth-value is indeterminable. |
| 9948 | Unlike objects, concepts are inherently incomplete [Frege, by George/Velleman] |
| Full Idea: For Frege, concepts differ from objects in being inherently incomplete in nature. | |
| From: report of Gottlob Frege (Function and Concept [1891]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.2 | |
| A reaction: This is because they are 'unsaturated', needing a quantified variable to complete the sentence. This could be a pointer towards Quine's view of properties, as simply an intrinsic feature of predication about objects, with no separate identity. |
| 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. |
| 4972 | I may regard a thought about Phosphorus as true, and the same thought about Hesperus as false [Frege] |
| Full Idea: From sameness of meaning there does not follow sameness of thought expressed. A fact about the Morning Star may express something different from a fact about the Evening Star, as someone may regard one as true and the other false. | |
| From: Gottlob Frege (Function and Concept [1891], p.14) | |
| A reaction: This all gets clearer if we distinguish internalist and externalist theories of content. Why take sides on this? Why not just ask 'what is in the speaker's head?', 'what does the sentence mean in the community?', and 'what is the corresponding situation?' |
| 23692 | Good and bad are a matter of actions, not of internal dispositions [Foot] |
| Full Idea: Some philosophers insist that dispositions, motives and other 'internal' elements are the primary determinants of moral goodness and badness. I have never been a 'virtue ethicist' is this sense. For me it is what is done that stands in this position. | |
| From: Philippa Foot (Rationality and Goodness [2004], p.2), quoted by John Hacker-Wright - Philippa Foot's Moral Thought 4 'Virtue' | |
| A reaction: [She mentions Hursthouse, Slote, Swanton] I'm quite struck by this. Aristotle insists that morality concerns actions. It doesn't seem that a person could be a saint by having wonderful dispositions, but doing nothing. Paraplegics? |
| 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. |
| 8491 | The Ontological Argument fallaciously treats existence as a first-level concept [Frege] |
| Full Idea: The ontological proof of God's existence suffers from the fallacy of treating existence as a first-level concept. | |
| From: Gottlob Frege (Function and Concept [1891], p.38 n) | |
| A reaction: [See Idea 8490 for first- and second-order functions] This is usually summarised as the idea that existence is a quantifier rather than a predicate. |