40 ideas
| 7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
| Full Idea: C.I.Lewis constructed five axiomatic systems of modal logic, and named them S1 to S5. It turns out that the simplest of the logics based on possible worlds is the same as Lewis's S5. | |
| From: report of C.I. Lewis (works [1935]) by Rod Girle - Modal Logics and Philosophy 2.1 | |
| A reaction: Nathan Salmon ('Reference and Essence' 2nd ed) claims (on p.xvii) that "the correct modal logic is weaker than S5 and weaker even than S4". Which is the greater virtue, simplicity or weakness? |
| 9358 | There are several logics, none of which will ever derive falsehoods from truth [Lewis,CI] |
| Full Idea: The fact is that there are several logics, markedly different, each self-consistent in its own terms and such that whoever, using it, avoids false premises, will never reach a false conclusion. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.366) | |
| A reaction: As the man who invented modal logic in five different versions, he speaks with some authority. Logicians now debate which version is the best, so how could that be decided? You could avoid false conclusions by never reasoning at all. |
| 9357 | Excluded middle is just our preference for a simplified dichotomy in experience [Lewis,CI] |
| Full Idea: The law of excluded middle formulates our decision that whatever is not designated by a certain term shall be designated by its negative. It declares our purpose to make a complete dichotomy of experience, ..which is only our penchant for simplicity. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.365) | |
| A reaction: I find this view quite appealing. 'Look, it's either F or it isn't!' is a dogmatic attitude which irritates a lot of people, and appears to be dispensible. Intuitionists in mathematics dispense with the principle, and vagueness threatens it. |
| 9364 | Names represent a uniformity in experience, or they name nothing [Lewis,CI] |
| Full Idea: A name must represent some uniformity in experience or it names nothing. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.368) | |
| A reaction: I like this because, in the quintessentially linguistic debate about the exact logical role of names, it reminds us that names arise because of the way reality is; they are not sui generis private games for logicians. |
| 11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
| Full Idea: C.I.Lewis's S4 system develops a sense of necessity as 'provability' in some fairly informal sense. | |
| From: report of C.I. Lewis (works [1935]) by Stephen Read - Thinking About Logic Ch. 4 |
| 9362 | Necessary truths are those we will maintain no matter what [Lewis,CI] |
| Full Idea: Those laws and those laws only have necessary truth which we are prepared to maintain, no matter what. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.367) | |
| A reaction: This bold and simple claim has famously been torpedoed by a well-known counterexample - that virtually every human being will cling on to the proposition "dogs have at some time existed" no matter what, but it clearly isn't a necessary truth. |
| 7803 | Modal logic began with translation difficulties for 'If...then' [Lewis,CI, by Girle] |
| Full Idea: C.I.Lewis began his groundbreaking work in modal logic because he was concerned about the unreliability of the material conditional as a translation of 'If ... then' conditionals. | |
| From: report of C.I. Lewis (Symbolic Logic (with Langford) [1932]) by Rod Girle - Modal Logics and Philosophy 12.3 | |
| A reaction: Compare 'if this is square then it has four corners' with 'if it rains then our afternoon is ruined'. Different modalities seem to be involved. We even find that 'a square has four corners' will be materially implied if it rains! |
| 9365 | We can maintain a priori principles come what may, but we can also change them [Lewis,CI] |
| Full Idea: The a priori contains principles which can be maintained in the face of all experience, representing the initiative of the mind. But they are subject to alteration on pragmatic grounds, if expanding experience shows their intellectual infelicity. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.373) | |
| A reaction: [compressed] This simply IS Quine's famous 'web of belief' picture, showing how firmly Quine is in the pragmatist tradition. Lewis treats a priori principles as a pragmatic toolkit, which can be refined to be more effective. Not implausible... |
| 21500 | We rely on memory for empirical beliefs because they mutually support one another [Lewis,CI] |
| Full Idea: When the whole range of empirical beliefs is taken into account, all of them more or less dependent on memorial knowledge, we find that those which are most credible can be assured by their mutual support, or 'congruence'. | |
| From: C.I. Lewis (An Analysis of Knowledge and Valuation [1946], 334), quoted by Erik J. Olsson - Against Coherence 3.1 | |
| A reaction: Lewis may be over-confident about this, and is duly attacked by Olson, but it seems to me roughly correct. How do you assess whether some unusual element in your memory was a dream or a real experience? |
| 21501 | If we doubt memories we cannot assess our doubt, or what is being doubted [Lewis,CI] |
| Full Idea: To doubt our sense of past experience as founded in actuality, would be to lose any criterion by which either the doubt itself or what is doubted could be corroborated. | |
| From: C.I. Lewis (An Analysis of Knowledge and Valuation [1946], 358), quoted by Erik J. Olsson - Against Coherence 3.3.1 | |
| A reaction: Obviously scepticism about memory can come in degrees, but total rejection of short-term and clear memories looks like a non-starter. What could you put in its place? Hyper-rationalism? Even maths needs memory. |
| 6556 | If anything is to be probable, then something must be certain [Lewis,CI] |
| Full Idea: If anything is to be probable, then something must be certain. | |
| From: C.I. Lewis (An Analysis of Knowledge and Valuation [1946], 186), quoted by Robert Fogelin - Walking the Tightrope of Reason Intro | |
| A reaction: Lewis makes this comment when facing infinite regress problems. It is a very nice slogan for foundationalism, which embodies the slippery slope view. Personally I feel the emotional pull of foundations, but acknowledge the very strong doubts about them. |
| 21498 | Congruents assertions increase the probability of each individual assertion in the set [Lewis,CI] |
| Full Idea: A set of statements, or a set of supposed facts asserted, will be said to be congruent if and only if they are so related that the antecedent probability of any one of them will be increased if the remainder of the set can be assumed as given premises. | |
| From: C.I. Lewis (An Analysis of Knowledge and Valuation [1946], 338), quoted by Erik J. Olsson - Against Coherence 2.2 | |
| A reaction: This thesis is vigorously attacked by Erik Olson, who works through the probability calculations. There seems an obvious problem without that. How else do you assess 'congruence', other than by evidence of mutual strengthening? |
| 5828 | Extension is the class of things, intension is the correct definition of the thing, and intension determines extension [Lewis,CI] |
| Full Idea: "The denotation or extension of a term is the class of all actual or existent things which the term correctly applies to or names; the connotation or intension of a term is delimited by any correct definition of it." ..And intension determines extension. | |
| From: C.I. Lewis (An Analysis of Knowledge and Valuation [1946]), quoted by Stephen P. Schwartz - Intro to Naming,Necessity and Natural Kinds §II | |
| A reaction: The last part is one of the big ideas in philosophy of language, which was rejected by Putnam and co. If you were to reverse the slogan, though, (to extension determines intension) how would you identify the members of the extension? |
| 9361 | We have to separate the mathematical from physical phenomena by abstraction [Lewis,CI] |
| Full Idea: Physical processes present us with phenomena in which the purely mathematical has to be separated out by abstraction. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.367) | |
| A reaction: This is the father of modal logic endorsing traditional abstractionism, it seems. He is also, though, endorsing the view that a priori knowledge is created by us, with pragmatic ends in view. |
| 20547 | We should respect the right of people to live in their own way, even if it is irrational [Swift] |
| Full Idea: Forcing people to do what is rational involves a lack of respect, a failure to respect the value of her living her life in her own (irrational) way. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 2 'Resisting' 6) | |
| A reaction: Up to a point. Irrationally eccentric is one thing, and irrationally self-destructive is another. You can sit back and watch your children embrace a life less happy than the one you wanted for them - but not a life of utter misery. |
| 20564 | Anti-colonial movements usually invoke the right of their 'people' to self-determination [Swift] |
| Full Idea: Nationalist movements seeking to throw off the yoke of colonial rule are often motivated by a sense that their 'people' have the right to self-determination. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 5 'Intrinsic 1') | |
| A reaction: In 2017, Basques, Catalans and Kurds come to mind. The whole of Africa was an example of this c.1950-80, but there was uncertainty about states, tribes and language groups. |
| 20535 | Isn't it more rational to maximise the average position, but with a safety net? [Swift] |
| Full Idea: Wouldn't it be more rational to choose principles that would maximize the average position, perhaps subject to some 'floor' level beneath which they would not want to take the risk of sinking? | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 1 'Rawls') | |
| A reaction: The criticism is that Rawls's prediction is over-cautious, and that people will take mild risks in what they choose, as long as there is no danger of disaster. (Just as you should allow small children to risk injury, but not death). |
| 20537 | Hypothetical contracts have no binding force [Swift] |
| Full Idea: A common objection to Rawls is that hypothetical contracts, unlike real ones, have no binding force. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 1 'Rawls') | |
| A reaction: [I think Dworkin made this point] 'Contract' may be metaphorical. Perhaps it is just an 'initial agreement' or a 'working arrangement', |
| 20542 | Cosmopolitans reject the right of different states to distribute resources in different ways [Swift] |
| Full Idea: Cosmopolitans who claim that the same distributive principles should apply to all human beings seem to be denying that different states may make different judgements about how they want to allocate resources among their members. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 1 'Social') | |
| A reaction: If you want to be a citizen of the world, you have to face up to the pluralistic character of cultures. Do you thereby want to be a citizen of both California and Saudi Arabia? Or are you actually just becoming a citizen of nowhere? |
| 20559 | Democracy is bad, but the other systems are worse [Swift] |
| Full Idea: During WW2 Winston Churchill famously said that democracy is the worst form of government, except for all the others that have been tried. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 5 'Procedures') | |
| A reaction: [Actually a speech in 1947, which began 'it has been said that....'] Aristotle thought an intelligent and benevolent dictatorship was the best form, but held little hope of achieving it. Getting rid of bad rulers is the big virtue. |
| 20561 | Since all opinions are treated as equal in democracy, it implies there are no right answers [Swift] |
| Full Idea: If there were moral knowledge about political matters, democracy would be a very strange way of reaching it. Democratic law-making means treating each person's view as equally good, which only makes sense if there is nothing to be right or wrong about. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 5 'Subjectivism') | |
| A reaction: Ah, I suddenly grasp that the modern fad for a rather gormless blanket relativism is rooted in the modern desire to take democracy really seriously. Important to remember Condorcet's point here. |
| 20562 | Design your democracy to treat citizens equally, or to produce better citizens? [Swift] |
| Full Idea: If your main reason for being a democrat is that democratic procedures respect citizens equally, then you may want a different kind of democracy from those who favour it because they think it tends to produce better citizens? | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 5 'Values') | |
| A reaction: [Combine this with Idea 20563] |
| 20563 | Design your democracy to yield political stability, or good decisions? [Swift] |
| Full Idea: If you value democracy because it yields political stability, then you will probably worry about different aspects of the procedure from those who care about its producing good decisions. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 5 'Values') | |
| A reaction: [Combine this with Idea 20562] Surely the primary aim must be good decisions? The other three options are the result of pessimism about any method achieving that. Instability, inequality and dud citizens are bars to good decisions. |
| 20560 | Teledemocracy omits debate and deliberation, which are important parts of good decisions [Swift] |
| Full Idea: We are averse to teledemocracy because it misses out some important parts of a good decision-making procedure, such as debate and deliberation. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 5 'Procedures') | |
| A reaction: Perhaps you should be sent a short info pack, and only allowed to vote when you have passed a factual multiple choice test about the topic. Or one pack from each political party. Maybe compulsory online discussion as well. |
| 20554 | Multiculturalism is a barrier to the whole state being a community [Swift] |
| Full Idea: For those wanting to regard the state itself as a community, multiculturalism can be a problem. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 4 'Liberalism') | |
| A reaction: A very important idea. A certain type of aggressive patriot passionately wants the whole country to be a close-bound community, and becomes deeply frustrated by the impossibility of this in a complex and fluid modern world. |
| 20553 | Liberals mistakenly think individuals choose their values, without reference to the community [Swift] |
| Full Idea: The two core liberal mistakes (according to communitarians) are that people choose their values, and that they do so in some way detached from their communities. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 4 'Correcting') | |
| A reaction: I think I might be a communitarian liberal, meaning that extreme individualism is both incorrect and pernicious, but that communities should only exist to promote the varied lives of individuals within them. |
| 20556 | The best way to build a cohesive community is to be involved in a war [Swift] |
| Full Idea: There is nothing like a war to build a sense of common purpose, of being in the same boat, and to generate the kind of interaction between people that breaks down divisive social boundaries. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014]) | |
| A reaction: A nice warning to those who over-do or simplify communitarianism. Alternatively, the greatest sign of health in a community is that citizens have almost no interest in one another? |
| 20557 | Membership and inclusion in a community implies non-membership and exclusion [Swift] |
| Full Idea: Community is about membership and inclusion. But that means it is also about non-membership and exclusion. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 4 'Conc') | |
| A reaction: I'm a fan of communitarianism (focused on Aristotle's life of individual virtue for each citizen), but I'm beginning to see that it has a poisonous cousin travelling under the same name. The cousin's rallying cries focus on aliens and enemies. |
| 20555 | Liberals are concerned to protect individuals from too much community [Swift] |
| Full Idea: Liberals are concerned to protect individuals from too much community - from practices that stifle the individual's freedom to choose for herself how she lives her life. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 4 'Liberalism') | |
| A reaction: The phrase 'too much community' is an excellent warning to communitarians. I'm happy to be enmeshed in a community, as long as it is composed of highly liberal and easy-going individuals. Avoid too much bad community. |
| 20540 | Redistributing wealth treats some people as means, rather than as ends [Swift] |
| Full Idea: Treating people as means seems like a fairly accurate description of what is involved when the state coercively redistributes resources from some to others. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 1 'Nozick') | |
| A reaction: The objection comes from Nozick, and alludes to Kant's desire to treat everyone as an end in themselves. Personally I don't mind at all being treated as a means, when my wife asks me to make her a cup of tea. Or paying my taxes to help the community. |
| 20551 | Men have had the power to structure all of our social institutions [Swift] |
| Full Idea: The problem for feminists is that men have had the power to structure all our social institutions - family, economy, polity - in ways that suit them. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 3 'Gender') | |
| A reaction: An interesting question is whether masculine domination runs even deeper than that, into our value system, our metaphysics, our science, our epistemology, our language. How do you tell? If women take over half the masculine roles, does that solve it? |
| 20545 | Maybe a freedom is from a restraint, and also in order to do something [Swift] |
| Full Idea: Maybe freedom is a triadic relation, involving an agent, freedom from a contraint, and in order to act towards some goal. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 2 'Two') | |
| A reaction: [He cites Gerald MacCallum for this thought] The point is that this makes freedom both negative and positive, contrary to Isaiah Berlin's claim. But on the first day of the school holidays you are 'free', with nothing in particular in mind. |
| 20550 | Opportunity should ignore extraneous factors, or foster competence, or ignore all disadvantages [Swift] |
| Full Idea: The minimal conception of equality of opportunity is that race or gender or religion should not affect chances of a good job or education. The conventional conception needs equality in acquiring competences. Radical views ignore inborn disadvantages. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 3 'Equality') | |
| A reaction: [my summary of Swift] The strong version only says the less talented should have access to large rewards. The whole idea has strong capitalist assumptions. |
| 20536 | Inequalities are needed, as incentives to do the most important jobs [Swift] |
| Full Idea: Without inequalities, people will have no incentive to do one job rather than another - to do the kind of work which is most useful. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 1 'Rawls') | |
| A reaction: The reality is that the lowest pay goes to the jobs that no one wants to do, and all the really nice jobs are usually well paid. Which is a conspiracy, because all the salaries are set by the people with the nice jobs. |
| 20548 | A person can desire redistibution of wealth, without it being for reasons of equality [Swift] |
| Full Idea: Someone who rejects equality can care passionately that resources should be transferred from the rich to the poor. They are just rejecting a particular reason that might be offered to justify the redistribution. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 3 'Intro') | |
| A reaction: For example, it might be for utilitarian reasons, which usually only seek maximised happiness, not equal happiness. And one may love many forms of equality, without economic equality being one of them. |
| 20541 | You can't necessarily sell your legitimate right to something, even if you produced it [Swift] |
| Full Idea: Ownership is a complicated idea. I have a right to the office photocopier, but I can's sell the right to others. If people have absolute rights over what they produce, why can't parents sell their children into slavery? | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 1 'Nozick') | |
| A reaction: If I make a car from stolen parts, does constructing it make it mine? Etc. Do birds own their nests? Swift goes on to ask if we 'own' our bodies. |
| 20546 | Libertarians about property ignore the fact that private property is a denial of freedoms [Swift] |
| Full Idea: Libertarians say that they care about freedom, and argue for private property rights on freedom grounds. But they don't sem to care about, or even notice, the unfreedom implied by the existence of private property rights. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 2 'Freedom') | |
| A reaction: When I pass some vast country estate totally surrounded by a high wall, I certainly don't think how wonderful it is that someone has the right to own this property as private land. On the contrary.... |
| 20533 | Justice can be seen as fairness or entitlement or desert [Swift] |
| Full Idea: The three influential conceptions of justice are as fairness (Rawls), as entitlement (Nozick), and as desert. | |
| From: Adam Swift (Political Philosophy (3rd ed) [2014], 1 'Concept') |
| 9363 | Science seeks classification which will discover laws, essences, and predictions [Lewis,CI] |
| Full Idea: The scientific search is for such classification as will make it possible to correlate appearance and behaviour, to discover law, to penetrate to the "essential nature" of things in order that behaviour may become predictable. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.368) | |
| A reaction: Modern scientific essentialists no longer invoke scare quotes, and I think we should talk of the search for the 'mechanisms' which explain behaviour, but Lewis seems to have been sixty years ahead of his time. |
| 1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |
| Full Idea: The Egyptians were the first to claim that the soul of a human being is immortal, and that each time the body dies the soul enters another creature just as it is being born. | |
| From: Herodotus (The Histories [c.435 BCE], 2.123.2) |