49 ideas
| 8092 | Logic was merely a branch of rhetoric until the scientific 17th century [Devlin] |
| Full Idea: Until the rise of what we call the scientific method in the seventeenth century, logic was regarded largely as one aspect of rhetoric - a study of how one person't argument could convince another. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch.11) | |
| A reaction: This may well give the main reason why the Greeks invented logic in the first place. Aristotle wrote a book on rhetoric, and that was where the money was. Leibniz is clearly a key figure in the change of attitude. |
| 9184 | We can't presume that all interesting concepts can be analysed [Williamson] |
| Full Idea: We have no prior reason to suppose that philosophically significant concepts have interesting analyses into necessary and sufficient conditions. | |
| From: Timothy Williamson (Review of Bob Hale's 'Abstract Objects' [1988]) | |
| A reaction: We might think that they are either analysable or primitive, and that failure of analysis invites us to take a concept as primitive. But maybe God can analyse it and we can't. |
| 8081 | 'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin] |
| Full Idea: Most people find it hard to find any conclusion that fits the following premises: 'No councillors are bankers', and 'All bankers are athletes'. There is a valid conclusion ('Some athletes are not councillors') but it takes quite an effort to find it. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 2) | |
| A reaction: A nice illustration of the fact that syllogistic logic is by no means automatic and straightforward. There is a mechanical procedure, but a lot of intuition and common sense is also needed. |
| 8085 | Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin] |
| Full Idea: Where Aristotle had 19 different inference rules (his valid syllogisms), modern propositional logic carries out deductions using just one rule of inference: modus ponens. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 4) | |
| A reaction: At first glance it sounds as if Aristotle's guidelines might be more useful than the modern one, since he tells you something definite and what implies what, where modus ponens just seems to define the word 'implies'. |
| 8086 | Predicate logic retains the axioms of propositional logic [Devlin] |
| Full Idea: Since predicate logic merely extends propositional logic, all the axioms of propositional logic are axioms of predicate logic. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 4) | |
| A reaction: See Idea 7798 for the axioms. |
| 8091 | Situation theory is logic that takes account of context [Devlin] |
| Full Idea: In many respects, situation theory is an extension of classical logic that takes account of context. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 8) | |
| A reaction: John Barwise is cited as the parent of this movement. Many examples show that logical form is very hard to pin down, because word-meaning depends on context (e.g. 'several crumbs' differs from 'several mountains'). |
| 8087 | Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin] |
| Full Idea: The period from 1900 to about 1960 could be described as the golden age of 'pure' logic, and 1950 to 1985 the golden age of 'applied' logic (e.g. applied to everyday reasoning, and to theories of language). | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 4) | |
| A reaction: Why do we always find that we have just missed the Golden Age? However this supports the uneasy feeling that the golden age for all advances in human knowledge is just coming to an end. Biology, including the brain, is the last frontier. |
| 8089 | Montague's intensional logic incorporated the notion of meaning [Devlin] |
| Full Idea: Montague's intensional logic was the first really successful attempt to develop a mathematical framework that incorporates the notion of meaning. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 8) | |
| A reaction: Previous logics, led by Tarski, had flourished by sharply dividing meaning from syntax, and concentrating on the latter. |
| 8082 | Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin] |
| Full Idea: Implication involves some form of link or causality between the antecedent and the consequent of an if-then; normally it says that the conclusion is a consequence of the premise (where conditionals are just defined by 'true' and 'false'). | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 2) | |
| A reaction: This distinction is a key one when discussing 'If-then' sentences. Some are merely formal conditionals, but others make real claims about where you can get to from where you are. |
| 8072 | Sentences of apparent identical form can have different contextual meanings [Devlin] |
| Full Idea: "Safety goggles must be worn in the building" is clear enough, but "dogs must always be carried on the escalator" doesn't require us to head off in search of a dog. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 1) | |
| A reaction: A nice illustration of how the requirements of logical form will often take us beyond the strict and literal meaning of a sentence, into context, tone, allusion and subjective aspects. |
| 8075 | Space and time are atomic in the arrow, and divisible in the tortoise [Devlin] |
| Full Idea: The arrow paradox starts with the assumption that space and time are atomic; the tortoise starts with the opposite assumption that space and time are infinitely divisible. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 2) | |
| A reaction: Aquinas similarly covers all options (the cosmos has a beginning, or no beginning). The nature of movement in a space which involves quantum leaps remains metaphysically puzzling. Where is a particle at half of the Planck time? |
| 9183 | Platonism claims that some true assertions have singular terms denoting abstractions, so abstractions exist [Williamson] |
| Full Idea: The Fregean argument for platonism is that some true assertions contain singular terms which denote abstract objects if they denote anything; since the assertions are true, the singular terms denote. | |
| From: Timothy Williamson (Review of Bob Hale's 'Abstract Objects' [1988]) | |
| A reaction: I am perplexed that anyone would rest their view of reality on such an argument. The obvious comparison would be with true remarks about blatantly fictional characters, or blatantly invented concepts such as 'checkmate'. |
| 8088 | People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin] |
| Full Idea: The Hopi time myth does not appear to have been stopped for a moment by the fact that Whorf himself subsequently wrote that the Hopi language does indeed have words for past, present, and future | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 5) | |
| A reaction: Arguments for relativism based on the Hopi seem now to be thoroughly discredited. Sensible people never believed them in the first place. |
| 20043 | Evolutionary explanations look to the past or the group, not to the individual [Stout,R] |
| Full Idea: In evolutionary explanations you may explain a population trait in terms of what it is for the sake of an individual, or explain it in terms of what it was for the sake of in earlier generations, but never in terms of what the trait is for the sake of. | |
| From: Rowland Stout (Action [2005], 2 'Functions') | |
| A reaction: So my ears are for the sake of my ability to hear, but that does not explain why I have ears. Should we say there is 'impersonal teleology' here, but no 'personal teleology'? Interesting. |
| 20058 | Not all explanation is causal. We don't explain a painting's beauty, or the irrationality of root-2, that way [Stout,R] |
| Full Idea: Not all explanation is causal. Explaining the beauty of a painting is not explaining why something happened. or why a move in chess is illegal, or why the square root of two is not a rational number. | |
| From: Rowland Stout (Action [2005], 5 'Argument') | |
| A reaction: It is surely plausible that the illegality of the chess move is caused (or 'determined', as I prefer to say) by the laws created for chess. The painting example seems right, though; what determined its configuration (think Pollock!) does not explain it. |
| 8073 | How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin] |
| Full Idea: How do people identify subject and verb in the sentences "time flies like an arrow" and "fruit flies like an apple"? | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 1) | |
| A reaction: A nice illustration of the fact that even if we have an innate syntax mechanism, it won't work without some semantics, and some experience of the environmental context of utterances. |
| 8076 | The distinction between sentences and abstract propositions is crucial in logic [Devlin] |
| Full Idea: The distinction between sentences and the abstract propositions that they express is one of the key ideas of logic. A logical argument consists of propositions, assembled together in a systematic fashion. | |
| From: Keith Devlin (Goodbye Descartes [1997], Ch. 2) | |
| A reaction: He may claim that arguments consist of abstract propositions, but they always get expressed in sentences. However, the whole idea of logical form implies the existence of propositions - there is something which a messy sentence 'really' says. |
| 20035 | Philosophy of action studies the nature of agency, and of deliberate actions [Stout,R] |
| Full Idea: The philosophy of action is concerned with the nature of agency: what it is to be a full-blown agent, and what it is to realise one's agency in acting deliberately on things. | |
| From: Rowland Stout (Action [2005], 1 'Being') | |
| A reaction: 'Full-blown' invites the question of whether there could be a higher level of agency, beyond the capacity of human beings. Perhaps AI should design a theoretical machine that taps into those higher levels, if we can conceive of them. Meta-coherence! |
| 20084 | Agency is causal processes that are sensitive to justification [Stout,R] |
| Full Idea: My conclusion is that wherever you can identify causal processes that are sensitive to the recommendations of systems of justification, there you have found agency. | |
| From: Rowland Stout (Action [2005], 9b 'Conclusion') | |
| A reaction: [the last paragraph of his book] Justification seems an awfully grand notion for a bee pollinating a flower, and I don't see human action as profoundly different. A reason might be a bad justification, but it might not even aspire to be a justification. |
| 20061 | Mental states and actions need to be separate, if one is to cause the other [Stout,R] |
| Full Idea: If psychological states and action results cannot be identified independently of one another, then it does not make sense to describe one as causing the other. | |
| From: Rowland Stout (Action [2005], 5 'Conclusion') | |
| A reaction: This summarises a widely cited unease about the causal theory of action. Any account in action theory will need to separate out some components and explain their interrelation. Otherwise actions are primitives, and we can walk away. |
| 20079 | Are actions bodily movements, or a sequence of intention-movement-result? [Stout,R] |
| Full Idea: Are actions identical with bodily movements? Or are they identical with sequences of things starting inside the agent's mind with their intentions, going through their body movements and finishing with the external results being achieved? | |
| From: Rowland Stout (Action [2005], 9 'What is action') | |
| A reaction: If bodily movements are crucial, this presumably eliminates speech acts. Speech or writing may involve some movement, but the movement is almost irrelevant to the nature of the action. Telepathy would do equally well. |
| 20080 | If one action leads to another, does it cause it, or is it part of it? [Stout,R] |
| Full Idea: When we do one action 'by' doing another, either the first action causes the process of the second, or the first action is part of the process of the second | |
| From: Rowland Stout (Action [2005], 9 'What is by') | |
| A reaction: Stout says the second view is preferable, because pressing a switch does not cause my action of turning on the light (though it does cause the light to come on). |
| 20059 | I do actions, but not events, so actions are not events [Stout,R] |
| Full Idea: I do not do an event; I do an action; so actions are not events. | |
| From: Rowland Stout (Action [2005], 5 'Are actions') | |
| A reaction: Sounds conclusive, but it places a lot of weight on the concepts of 'I' and 'do', which leaves room for some discussion. This point is opposed to the causal theory of action, because causation concerns events. |
| 20081 | Bicycle riding is not just bodily movement - you also have to be on the bicycle [Stout,R] |
| Full Idea: You do not ride a bicycle just by moving your body in a certain way. You have to be on the bicycle to move in the right sort of way | |
| From: Rowland Stout (Action [2005], 9 'Are body') | |
| A reaction: My favourite philosophical ideas are simple and conclusive. He also observes that walking involves the ground being walked on. In complex actions 'feedback' with the environment is involved. |
| 20044 | The rationalistic approach says actions are intentional when subject to justification [Stout,R] |
| Full Idea: The rationalistic approach to agency says that what characterises intentional action is that it is subject to justification. | |
| From: Rowland Stout (Action [2005], 2 'Conclusion') | |
| A reaction: [Anscombe is the chief articulator of this view] This seems to incorporate action into an entirely intellectual and even moral framework. |
| 20039 | The causal theory says that actions are intentional when intention (or belief-desire) causes the act [Stout,R] |
| Full Idea: The causal theory of action asserts that what characterises intentional action is the agent's intentions, or perhaps their beliefs and desires, causing their behaviour in the appropriate way. | |
| From: Rowland Stout (Action [2005], 1 'Outline') | |
| A reaction: The agent's intentions are either sui generis (see Bratman), or reducible to beliefs and desires (as in Hume). The classic problem for the causal theory is said to be 'deviant causal chains'. |
| 20047 | Deciding what to do usually involves consulting the world, not our own minds [Stout,R] |
| Full Idea: In the vast majority of actions you need to look outwards to work out what you should do. An exam invigilator should consult the clock to design when to end the exam, not her state of mind. | |
| From: Rowland Stout (Action [2005], 3 'The belief-') | |
| A reaction: Stout defends externalist intentions. I remain unconvinced. It is no good looking at a clock if you don't form a belief about what it says, and the belief is obviously closer than the clock to the action. Intellectual virtue requires checking the facts. |
| 20065 | Should we study intentions in their own right, or only as part of intentional action? [Stout,R] |
| Full Idea: Should we try to understand what it is to have an intention in terms of what it is to act intentionally, or should we try to understand what it is to have an intention independently of what it is to act intentionally? | |
| From: Rowland Stout (Action [2005], 7 'Acting') | |
| A reaction: Since you can have an intention to act, and yet fail to act, it seems possible to isolate intentions, but not to say a lot about them. Intention may be different prior to actions, and during actions. Early Davidson offered the derived view. |
| 20067 | You can have incompatible desires, but your intentions really ought to be consistent [Stout,R] |
| Full Idea: Intentions are unlike desires. You can simultaneously desire two things that you know are incompatible. But when you form intentions you are embarking on a course of action, and there is a much stronger requirement of consistency. | |
| From: Rowland Stout (Action [2005], 7 'Relationship') | |
| A reaction: I'm not sure why anyone would identify intentions with desires. I would quite like to visit Japan, but have no current intention of doing so. I assume that the belief-plus-desire theory doesn't deny that an uninteresting intention is also needed. |
| 20078 | The normativity of intentions would be obvious if they were internal promises [Stout,R] |
| Full Idea: One way to incorporate this [normative] feature of intentions would be to treat them like internal promises. | |
| From: Rowland Stout (Action [2005], 8 'Intention') | |
| A reaction: Interesting. The concept of a promise is obviously closely linked to an intention. If you tell your companion exactly where you intend your golf ball to land, you can thereby be held accountable, in a manner resembling a promise (but not a promise). |
| 20036 | Intentional agency is seen in internal precursors of action, and in external reasons for the act [Stout,R] |
| Full Idea: It is plausible that we find something characteristic of intentional agency when we look inward to the mental precursors of actions, and also when we look outward, to the sensitivity of action to what the environment gives us reasons to do. | |
| From: Rowland Stout (Action [2005], 1 'How') | |
| A reaction: This is Stout staking a claim for his partly externalist view of agency. I warm less and less to the various forms of externalism. How often does the environment 'give us reasons' to do things? How can we act, without internalising those reasons? |
| 20066 | Speech needs sustained intentions, but not prior intentions [Stout,R] |
| Full Idea: The intentional action of including the word 'big' in a sentence does not require a prior intention to say it. What is required is that you say it with the intention of saying it. | |
| From: Rowland Stout (Action [2005], 7 'Relationship') | |
| A reaction: This seems right, but makes it a lot harder to say what an intention is, and to separate it out for inspection. You can't speak a good English sentence while withdrawing the intention involved. |
| 20073 | Bratman has to treat shared intentions as interrelated individual intentions [Stout,R] |
| Full Idea: Bratman has to construe what we think of as shared intentions as not literally involving shared intentions, but as involving interrelating of individual intentions. | |
| From: Rowland Stout (Action [2005], 7 'Conclusion') | |
| A reaction: Stout rejects this, for an account based on adaptability of behaviour. To me, naturalism and sparse ontology favour Bratman (1984) . I like my idea that shared intentions are conditional individual intentions. If the group refuses, I drop the intention. |
| 20069 | A request to pass the salt shares an intention that the request be passed on [Stout,R] |
| Full Idea: When one person says to another 'please pass the salt', and the other engages with this utterance and understands it, they share the intention that this request is passed from the first person to the second. | |
| From: Rowland Stout (Action [2005], 7 'Shared') | |
| A reaction: Simple and intriguing. We form an intention, and then ask someone else to take over our intention. When the second person takes over the intention, I give up the intention to acquire the salt, because it is on its way. It's political. |
| 20070 | An individual cannot express the intention that a group do something like moving a piano [Stout,R] |
| Full Idea: It is unnatural to describe an individual as intending that the group do something together. ...What could possibly express my intention that we move the piano upstairs? | |
| From: Rowland Stout (Action [2005], 7 'Shared') | |
| A reaction: Two possible answers: it makes sense if I have great authority within the group. 'I'm going to move the piano - you take that end'. Or, such expressions are implicitly conditional - 'I intend to move the piano (if you will also intend it)'. |
| 20071 | An intention is a goal to which behaviour is adapted, for an individual or for a group [Stout,R] |
| Full Idea: An individual intention is a goal to which an individual's behaviour adapts. A shared intention is a goal to which a group of people's behaviour collectively adapts. | |
| From: Rowland Stout (Action [2005], 7 'Shared') | |
| A reaction: This is part of Stout's externalist approach to actions. One would have thought that an intention was a state of mind, not a goal in the world. The individual's goal can be psychological, but a group's goal has to be an abstraction. |
| 20038 | If the action of walking is just an act of will, then movement of the legs seems irrelevant [Stout,R] |
| Full Idea: If volitionism identifies the action with an act of will, this has the unpalatable consequence (for a Cartesian dualist) that walking does not happen in the material world. It would be the same act of walking if you had no legs, or no body at all. | |
| From: Rowland Stout (Action [2005], 1 'Volitionism') | |
| A reaction: Is this attacking a caricature version of volitionism? Descartes would hardly subscribe to the view that no legs are needed for walking. If my legs spasmodically move without an act of will, we typically deny that this is an action. |
| 20050 | Most philosophers see causation as by an event or state in the agent, rather than the whole agent [Stout,R] |
| Full Idea: Most philosophers are uneasy with understanding the causal aspect of actions in terms of an 'agent' making something happen. They prefer to think of some event in the agent, or state of the agent, making something happen. | |
| From: Rowland Stout (Action [2005], 4 'The causal') | |
| A reaction: There is a bit of a regress if you ask what caused the event or state of affairs. It is tempting to stop the buck at the whole agent, or else carry the reduction on down to neurons, physics and the outside world. |
| 20052 | If you don't mention an agent, you aren't talking about action [Stout,R] |
| Full Idea: Once you lose the agent from an account of action it stops being an account of action at all. | |
| From: Rowland Stout (Action [2005], 4 'Agent') | |
| A reaction: [he refers to Richard Taylor 1966] This could be correct without implying that agents offer a unique mode of causation. The concept of 'agent' is reducible. |
| 20077 | If you can judge one act as best, then do another, this supports an inward-looking view of agency [Stout,R] |
| Full Idea: Weakness of will is a threat to the outward-looking approach to agency. It seems you can hold one thing to be the thing to do, and at the same time do something else. Many regard this as a decisive reason to follow a more inward-looking approach. | |
| From: Rowland Stout (Action [2005], 8 'Weakness') | |
| A reaction: It hadn't struck me before that weakness of will is a tool for developing an accurate account of what is involved in normal agency. Some facts that guide action are internal to the agent, such as greed for sugary cakes. |
| 20049 | Maybe your emotions arise from you motivations, rather than being their cause [Stout,R] |
| Full Idea: Instead of assuming that your motivation depends on your emotional state, we might say that your emotional state depends on how you are motivated to act. | |
| From: Rowland Stout (Action [2005], 3 'Emotions') | |
| A reaction: [He says this move is made by Kant, Thomas Nagel and McDowell] Stout favours the view that it is external facts which mainly give rise to actions, and presumably these facts are intrinsically motivating, prior to any emotions. I don't disagree. |
| 20046 | For an ascetic a powerful desire for something is a reason not to implement it [Stout,R] |
| Full Idea: If wanting something most were the same as having the most powerful feelings about it, then as an ascetic (rejecting what you most powerfully desire), your wanting most to eat a bun would be your reason for not eating the bun. | |
| From: Rowland Stout (Action [2005], 3 'The belief-') | |
| A reaction: This sounds like reason overruling desire, but the asceticism can always be characterised as a meta-desire. |
| 20060 | Beliefs, desires and intentions are not events, so can't figure in causal relations [Stout,R] |
| Full Idea: Beliefs, desires and intentions are states of mind rather than events, but events are the only things that figure in causal relations. | |
| From: Rowland Stout (Action [2005], 5 'Do beliefs') | |
| A reaction: This is exactly why we have the concept of 'the will' - because it is a mental state to which we attribute active causal powers. We then have to explain how this 'will' is related to the other mental states (which presume motivate or drive it?). |
| 20055 | A standard view says that the explanation of an action is showing its rational justification [Stout,R] |
| Full Idea: The idea running through the work of Aristotle, Kant, Anscombe and Davidson is that explanation of action involves justifying that action or making it rationally intelligible. | |
| From: Rowland Stout (Action [2005], 5 'Psychological') | |
| A reaction: Stout goes on to say that instead you could give the 'rationalisation' of the action, which is psychological facts which explain the action, without justifying it. The earlier view may seem a little optimistic and intellectualist. |
| 20056 | In order to be causal, an agent's reasons must be internalised as psychological states [Stout,R] |
| Full Idea: It is widely accepted that to get involved in the causal process of acting an agent's reasons must be internalised as psychological states. | |
| From: Rowland Stout (Action [2005], 5 'Psychological') | |
| A reaction: This doesn't say whether the 'psychological states' have to be fully conscious. That seems unlikely, given the speed with which we perform some sequences of actions, such as when driving a car, or playing a musical instrument. |
| 20053 | An action is only yours if you produce it, rather than some state or event within you [Stout,R] |
| Full Idea: For action to be properly yours it must be you who is the causal originator of the action, rather than some state or event within you. | |
| From: Rowland Stout (Action [2005], 4 'Agent') | |
| A reaction: [He invokes Chisholm 1966] The idea here is that we require not only 'agent causation', but that the concept of agent must include free will. It seems right we ought to know whether or not an action is 'mine'. Nothing too fancy is needed for this! |
| 20048 | There may be a justification relative to a person's view, and yet no absolute justification [Stout,R] |
| Full Idea: In a relativistic notion of justification, in a particular system, there is a reason for a vandal to smash public property, even though, using an absolute conception of justification, there is no reason for him to do so. | |
| From: Rowland Stout (Action [2005], 3 'The difference') | |
| A reaction: I suppose Kantians would say that the aim of morality is to make your personal (relative) justification coincide with what seems to be the absolute justification. |
| 20068 | Describing a death as a side-effect rather than a goal may just be good public relations [Stout,R] |
| Full Idea: The real signficance of the doctrine of double effect can be public relations. You can put a better spin on an action by describing a death as an unfortunate collateral consequence, rather than as a goal of the action | |
| From: Rowland Stout (Action [2005], 7 'Doctrine') | |
| A reaction: The problem is that it the principle is usually invoked in situations where it is not clear where some bad effect is intended, and it is very easy to lie in such situations. In football, we can never quite decide whether a dangerous tackle was intended. |
| 20083 | Aristotelian causation involves potentiality inputs into processes (rather than a pair of events) [Stout,R] |
| Full Idea: In the Aristotelian approach to causation (unlike the Humean approach, involving separate events), A might cause B by being an input into some process (realisation of potentiality) that results in B. | |
| From: Rowland Stout (Action [2005], 9 'Trying') | |
| A reaction: Stout relies quite heavily on this view for his account of human action. I like processes, so am sympathetic to this view. If there are two separate events, it is not surprising that Hume could find nothing to bridge the gap between them. |