73 ideas
| 17016 | Philosophy must abstract from the senses [Newton] |
| Full Idea: In philosophy abstraction from the senses is required. | |
| From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol) | |
| A reaction: He particularly means 'natural philosophy' (i.e. science), but there is no real distinction in Newton's time, and I would say this remark is true of modern philosophy. |
| 18079 | Newton developed a kinematic approach to geometry [Newton, by Kitcher] |
| Full Idea: The reduction of the problems of tangents, normals, curvature, maxima and minima were effected by Newton's kinematic approach to geometry. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Philip Kitcher - The Nature of Mathematical Knowledge 10.1 | |
| A reaction: This approach apparently contrasts with that of Leibniz. |
| 18082 | Quantities and ratios which continually converge will eventually become equal [Newton] |
| Full Idea: Quantities and the ratios of quantities, which in any finite time converge continually to equality, and, before the end of that time approach nearer to one another by any given difference become ultimately equal. | |
| From: Isaac Newton (Principia Mathematica [1687], Lemma 1), quoted by Philip Kitcher - The Nature of Mathematical Knowledge 10.2 | |
| A reaction: Kitcher observes that, although Newton relies on infinitesimals, this quotation expresses something close to the later idea of a 'limit'. |
| 17011 | I suspect that each particle of bodies has attractive or repelling forces [Newton] |
| Full Idea: Many things lead me to a suspicion that all phenomena may depend on certain forces by which the particles of bodies, by causes not yet known, either are impelled toward one another and cohere in regular figures,or are repelled from one another and recede. | |
| From: Isaac Newton (Principia Mathematica [1687], Pref) | |
| A reaction: For Newton, forces are not just abstractions that are convenient for mathematics, but realities which I would say are best described as 'powers'. |
| 17028 | Particles mutually attract, and cohere at short distances [Newton] |
| Full Idea: The particles of bodies attract one another at very small distances and cohere when they become contiguous. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol) | |
| A reaction: This is the sort of account of unity which has to be given in the corpuscular view of things, once substantial forms are given up. What is missing here is the structure of the thing. A lump of dirt is as unified as a cat in this story. |
| 17014 | The place of a thing is the sum of the places of its parts [Newton] |
| Full Idea: The place of a whole is the same as the sum of the places of the parts, and is therefore internal and in the whole body. | |
| From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol) | |
| A reaction: Note that Newton is talking of the sums of places, and deriving them from the parts. This is the mereology of space. |
| 17546 | If you changed one of Newton's concepts you would destroy his whole system [Heisenberg on Newton] |
| Full Idea: The connection between the different concept in [Newton's] system is so close that one could generally not change any one of the concepts without destroying the whole system | |
| From: comment on Isaac Newton (Principia Mathematica [1687]) by Werner Heisenberg - Physics and Philosophy 06 | |
| A reaction: This holistic situation would seem to count against Newton's system, rather than for it. A good system should depend on nature, not on other parts of the system. Compare changing a rule of chess. |
| 17027 | Science deduces propositions from phenomena, and generalises them by induction [Newton] |
| Full Idea: In experimental philosophy, propositions are deduced from the phenomena and are made general by induction. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol) | |
| A reaction: Sounds easy, but generalising by induction requires all sorts of assumptions about the stability of natural kinds. Since the kinds are only arrived at by induction, it is not easy to give a proper account here. |
| 17022 | We should admit only enough causes to explain a phenomenon, and no more [Newton] |
| Full Idea: No more causes of natural things should be admitted than are both true and sufficient to explain the phenomena. …For nature does nothing in vain, …and nature is simple and does not indulge in the luxury of superfluous causes. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Rule 1) | |
| A reaction: This emphasises that Ockham's Razor is a rule for physical explanation, and not just one for abstract theories. This is something like Van Fraassen's 'empirical adequacy'. |
| 17021 | Natural effects of the same kind should be assumed to have the same causes [Newton] |
| Full Idea: The causes assigned to natural effects of the same kind must be, so far as possible, the same. For example, the cause of respiration in man and beast. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Rule 2) | |
| A reaction: It is impossible to rule out identical effects from differing causes, but explanation gets much more exciting (because wide-ranging) if Newton's rule is assumed. |
| 17026 | From the phenomena, I can't deduce the reason for the properties of gravity [Newton] |
| Full Idea: I have not as yet been able to deduce from the phenomena the reason for the properties of gravity. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol) | |
| A reaction: I take it that giving the reasons for the properties of gravity would be an essentialist explanation. I am struck by the fact that the recent discovery of the Higgs Boson appears to give us a reason why things have mass (i.e. what causes mass). |
| 7357 | People who control others with fluent language often end up being hated [Kongzi (Confucius)] |
| Full Idea: Of what use is eloquence? He who engages in fluency of words to control men often finds himself hated by them. | |
| From: Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE], V.5) | |
| A reaction: I don't recall Socrates making this very good point to any of the sophists (such as Gorgias). The idea that if you battle or connive your way to dominance over others then you are successful is false. Life is a much longer game than that. |
| 7358 | All men prefer outward appearance to true excellence [Kongzi (Confucius)] |
| Full Idea: I have yet to meet a man as fond of excellence as he is of outward appearances. | |
| From: Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE], IX.18) | |
| A reaction: Interestingly, this cynical view of the love of virtue is put by Plato into the mouths of Glaucon and Adeimantus (in Bk II of 'Republic', e.g. Idea 12), and not into the mouth of Socrates, who goes on to defend the possibility of true virtue. |
| 7362 | Humans are similar, but social conventions drive us apart (sages and idiots being the exceptions) [Kongzi (Confucius)] |
| Full Idea: In our natures we approximate one another; habits put us further and further apart. The only ones who do not change are sages and idiots. | |
| From: Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE], XVII.2) | |
| A reaction: I find most of Confucius rather uninteresting, but this is a splendid remark about the influence of social conventions on human nature. Sages can achieve universal morality if they rise above social convention, and seek the true virtues of human nature. |
| 7360 | Do not do to others what you would not desire yourself [Kongzi (Confucius)] |
| Full Idea: Do not do to others what you would not desire yourself. Then you will have no enemies, either in the state or in your home. | |
| From: Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE], XII.2) | |
| A reaction: The Golden Rule, but note the second sentence. Logically, it leads to the absurdity of not giving someone an Elvis record for Christmas because you yourself don't like Elvis. Kant (Idea 3733) and Nietzsche (Idea 4560) offer good criticisms. |
| 7359 | Excess and deficiency are equally at fault [Kongzi (Confucius)] |
| Full Idea: Excess and deficiency are equally at fault. | |
| From: Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE], XI.16) | |
| A reaction: This is the sort of wisdom we admire in Aristotle (and in any sensible person), but it may also be the deepest motto of conservatism, and it is a long way from romantic philosophy, and the clarion call of Nietzsche to greater excitement in life. |
| 7363 | The virtues of the best people are humility, maganimity, sincerity, diligence, and graciousness [Kongzi (Confucius)] |
| Full Idea: He who in this world can practise five things may indeed be considered Man-at-his-best: humility, maganimity, sincerity, diligence, and graciousness. | |
| From: Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE], XVII.5) | |
| A reaction: A very nice list. Who could resist working with a colleague who had such virtues? Who could go wrong if they married a person who had them? I can't think of anything important that is missing. |
| 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? |
| 7361 | Men of the highest calibre avoid political life completely [Kongzi (Confucius)] |
| Full Idea: Men of the highest calibre avoid political life completely. | |
| From: Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE], XIV.37) | |
| A reaction: Plato notes that such people tend to avoid political life (and a left sheltering, as if from a wild storm!), but he thinks they should be dragged into the political arena for the common good. Confucius seems to approve of the avoidance. Plato is right. |
| 23393 | Confucianism assumes that all good developments have happened, and there is only one Way [Norden on Kongzi (Confucius)] |
| Full Idea: The two major limitations of Confucianism are that it assumes that all worthwhile cultural, social and ethical innovation has already occurred, and that it does not recognise the plurality of worthwhile ways of life. | |
| From: comment on Kongzi (Confucius) (The Analects (Lunyu) [c.511 BCE]) by Bryan van Norden - Intro to Classical Chinese Philosophy 3.III | |
| A reaction: In modern liberal terms that is about as conservative as it is possible to get. We think of it as the state of mind of an old person who can only long for the way things were when they were young. But 'hold fast to that which is good'! |
| 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') |
| 6421 | Newton's four fundamentals are: space, time, matter and force [Newton, by Russell] |
| Full Idea: Newton works with four fundamental concepts: space, time, matter and force. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Bertrand Russell - My Philosophical Development Ch.2 | |
| A reaction: The ontological challenge is to reduce these in number, presumably. They are, notoriously, defined in terms of one another. |
| 13470 | Mass is central to matter [Newton, by Hart,WD] |
| Full Idea: For Newton, mass is central to matter. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by William D. Hart - The Evolution of Logic 2 | |
| A reaction: On reading this, I realise that this is the concept of matter I have grown up with, one which makes it very hard to grasp what the Greeks were thinking of when they referred to matter [hule]. |
| 17020 | An attraction of a body is the sum of the forces of their particles [Newton] |
| Full Idea: The attractions of the bodies must be reckoned by assigning proper forces to their individual particles and then taking the sums of those forces. | |
| From: Isaac Newton (Principia Mathematica [1687], 1.II.Schol) | |
| A reaction: This is using the parts of bodies to give fundamental explanations, rather than invoking substantial forms. The parts need not be atoms. |
| 23012 | Newtonian causation is changes of motion resulting from collisions [Newton, by Baron/Miller] |
| Full Idea: In the Newtonian mechanistic theory of causation, ….something causes a result when it brings about a change of motion. …Causation is a matter of things bumping into one another. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Baron,S/Miller,K - Intro to the Philosophy of Time 6.2.1 | |
| A reaction: This seems to need impenetrability and elasticity as primitives (which is partly what Leibniz's monads are meant to explain). The authors observe that much causation is the result of existences and qualities, rather than motions. |
| 17008 | You have discovered that elliptical orbits result just from gravitation and planetary movement [Newton, by Leibniz] |
| Full Idea: You have made the astonishing discovery that Kepler's ellipses result simply from the conception of attraction or gravitation and passage in a planet. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Gottfried Leibniz - Letter to Newton 1693.03.07 | |
| A reaction: I quote this to show that Newton made 'an astonishing discovery' of a connection in nature, and did not merely produce an equation which described a pattern of behaviour. The simple equation is the proof of the connection. |
| 17010 | We have given up substantial forms, and now aim for mathematical laws [Newton] |
| Full Idea: The moderns - rejecting substantial forms and occult qualities - have undertaken to reduce the phenomena of nature to mathematical laws. | |
| From: Isaac Newton (Principia Mathematica [1687], Preface) | |
| A reaction: This is the simplest statement of the apparent anti-Aristotelian revolution in the seventeenth century. |
| 17023 | I am not saying gravity is essential to bodies [Newton] |
| Full Idea: I am by no means asserting that gravity is essential to bodies. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Rule 3) | |
| A reaction: Notice that in Idea 17009 he does not rule out gravity being essential to bodies. This is Newton's intellectual modesty (for which he is not famous). |
| 15866 | Newton reclassified vertical motion as violent, and unconstrained horizontal motion as natural [Newton, by Harré] |
| Full Idea: Following Kepler, Newton assumed a law of universal gravitation, thus reclassifying free fall as a violent motion and, with his First Law, fixing horizontal motion in the absence of constraints as natural | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Rom Harré - Laws of Nature 1 | |
| A reaction: This is in opposition to the Aristotelian view, where the downward motion of physical objects is their natural motion. |
| 15958 | Inertia rejects the Aristotelian idea of things having natural states, to which they return [Newton, by Alexander,P] |
| Full Idea: Newton's principle of inertia implies a rejection of the Aristotelian idea of natural states to which things naturally return. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Peter Alexander - Ideas, Qualities and Corpuscles 02.3 | |
| A reaction: I think we can safely say that Aristotle was wrong about this. Aristotle made too much (such as the gravity acting on a thing) intrinsic to the bodies, when the whole context must be seen. |
| 17017 | 1: Bodies rest, or move in straight lines, unless acted on by forces [Newton] |
| Full Idea: Law 1: Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by forces impressed. | |
| From: Isaac Newton (Principia Mathematica [1687], Axioms) | |
| A reaction: This is the new concept of inertia, which revolutionises the picture. Motion itself, which was a profound puzzle for the Greeks, ceases to be a problem by being axiomatised. It is now acceleration which is the the problem. |
| 17018 | 2: Change of motion is proportional to the force [Newton] |
| Full Idea: Law 2: A change in motion is proportional to the motive force impressed and takes place along the straight line in which that force is impressed. | |
| From: Isaac Newton (Principia Mathematica [1687], Axioms) | |
| A reaction: This gives the equation 'force = mass x acceleration', where the mass is the constant needed for the equation of proportion. Effectively mass is just the value of a proportion. |
| 20968 | Newton's Third Law implies the conservation of momentum [Newton, by Papineau] |
| Full Idea: Newton's Third Law implies the conservation of momentum, because 'action and reaction' are always equal. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3 | |
| A reaction: That is, the Third Law implies the First Law (which is the Law of Momentum). |
| 17019 | 3: All actions of bodies have an equal and opposite reaction [Newton] |
| Full Idea: Law 3: To any action there is always an opposite and equal reaction; in other words, the action of two bodies upon each other are always equal and always opposite in direction. | |
| From: Isaac Newton (Principia Mathematica [1687], Axioms) | |
| A reaction: Is this still true if one body is dented by the impact and the other one isn't? What counts as a 'body'? |
| 17547 | Newton's idea of force acting over a long distance was very strange [Heisenberg on Newton] |
| Full Idea: Newton introduced a very new and strange hypothesis by assuming a force that acted over a long distance. | |
| From: comment on Isaac Newton (Principia Mathematica [1687]) by Werner Heisenberg - Physics and Philosophy 06 | |
| A reaction: Why would a force that acted over a short distance be any less mysterious? |
| 20966 | Newton introduced forces other than by contact [Newton, by Papineau] |
| Full Idea: Newton allowed forces other than impact. All the earlier proponents of 'mechanical philosophy' took it as given that all physical action is by contact. ...He thought of 'impressed force' - disembodied entities acting from outside a body. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3 | |
| A reaction: This is 'action at a distance', which was as bewildering then as quantum theory is now. Newton had a divinity to impose laws of nature from the outside. In some ways we have moved back to the old view, with the actions of bosons and fields. |
| 20967 | Newton's laws cover the effects of forces, but not their causes [Newton, by Papineau] |
| Full Idea: Newton has a general law about the effects of his forces, ...but there is no corresponding general principle about the causes of such forces. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3 | |
| A reaction: I'm not sure that Einstein gives a cause of gravity either. This seems to be part of the scientific 'instrumentalist' view of nature, which is incredibly useful but very superficial. |
| 16708 | Newton's forces were accused of being the scholastics' real qualities [Pasnau on Newton] |
| Full Idea: Newton's reliance on the notion of force was widely criticised as marking in effect a return to real qualities. | |
| From: comment on Isaac Newton (Principia Mathematica [1687]) by Robert Pasnau - Metaphysical Themes 1274-1671 19.7 | |
| A reaction: The objection is to forces that are separate from the bodies they act on. This is one of the reasons why modern metaphysics needs the concept of an intrinsic disposition or power, placing the forces in the stuff. |
| 13153 | I am studying the quantities and mathematics of forces, not their species or qualities [Newton] |
| Full Idea: I consider in this treatise not the species of forces and their physical qualities, but their quantities and mathematical proportions. | |
| From: Isaac Newton (Principia Mathematica [1687], 1.1.11 Sch) | |
| A reaction: Note that Newton is not denying that one might contemplate the species and qualities of forces, as I think Leibniz tried to do, thought he didn't cast any detailed light on them. It is the gap between science and metaphysics. |
| 12724 | The aim is to discover forces from motions, and use forces to demonstrate other phenomena [Newton] |
| Full Idea: The basic problem of philosophy seems to be to discover the forces of nature from the phenomena of motions and then to demonstrate the other phenomena from these forces. | |
| From: Isaac Newton (Principia Mathematica [1687], Pref 1st ed), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 4 | |
| A reaction: This fits in with the description-of-regularity approach to laws which Newton had acquired from Galileo, rather than the essentialist attitude to forces of Leibniz, though Newton has smatterings of essentialism. |
| 13593 | Newton showed that falling to earth and orbiting the sun are essentially the same [Newton, by Ellis] |
| Full Idea: Newton showed that the apparently different kinds of processes of falling towards the earth and orbiting the sun are essentially the same. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Brian Ellis - Scientific Essentialism 3.08 | |
| A reaction: I quote this to illustrate Newton's permanent achievement in science, in the face of a tendency to say that he was 'outmoded' by the advent of General Relativity. Newton wasn't interestingly wrong. He was very very right. |
| 20969 | Early Newtonians could not formulate conservation of energy, having no concept of potential energy [Newton, by Papineau] |
| Full Idea: A barrier to the formulation of an energy conservation principle by early Newtonians was their lack of a notion of potential energy. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3 n5 | |
| A reaction: Interestingly, the notions of potentiality and actuality were central to Aristotle, but Newtonians had just rejected all of that. |
| 17013 | Absolute space is independent, homogeneous and immovable [Newton] |
| Full Idea: Absolute space, of its own nature without reference to anything external, always remains homogeneous and immovable. | |
| From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol) | |
| A reaction: This would have to be a stipulation, rather than an assertion of fact, since whether space is 'immovable' is either incoherent or unknowable. |
| 22915 | Newton needs intervals of time, to define velocity and acceleration [Newton, by Le Poidevin] |
| Full Idea: Both Newton's First and Second Laws of motion make implicit reference to equal intervals of time. For a body is moving with constant velocity if it covers the same distance in a series of equal intervals (and similarly with acceleration). | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Robin Le Poidevin - Travels in Four Dimensions 01 'Time' | |
| A reaction: [Le Poidevin spells out the acceleration point] You can see why he needs time to be real, if measured chunks of it figure in his laws. |
| 22893 | Newton thought his laws of motion needed absolute time [Newton, by Bardon] |
| Full Idea: Newton's reason for embracing absolute space, time and motion was that he thought that universal laws of motions were describable only in such terms. Because actual motions are irregular, the time of universal laws of motion cannot depend on them. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by Adrian Bardon - Brief History of the Philosophy of Time 3 'Replacing' | |
| A reaction: I'm not sure of the Einsteinian account of the laws of motion. |
| 17012 | Time exists independently, and flows uniformly [Newton] |
| Full Idea: Absolute, true, and mathematical time, in and of itself and of its own nature, without reference to anything external, flows uniformly and by another name is called duration. | |
| From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol) | |
| A reaction: This invites the notorious question of, if time flows uniformly, how fast time flows. Maybe we should bite the bullet and say 'one second per second', or maybe we should say 'this fact is beyond our powers of comprehension'. |
| 14012 | Absolute time, from its own nature, flows equably, without relation to anything external [Newton] |
| Full Idea: Absolute, true, and mathematical time, of itself, and from its own nature, flows equably, without relation to anything external. | |
| From: Isaac Newton (Principia Mathematica [1687], I:Schol after defs), quoted by Craig Bourne - A Future for Presentism 5.1 | |
| A reaction: I agree totally with this, and I don't care what any modern relativity theorists say. It think Shoemaker's argument gives wonderful support to Newton. |
| 22954 | Newtonian mechanics does not distinguish negative from positive values of time [Newton, by Coveney/Highfield] |
| Full Idea: In Newton's laws of motion time is squared, so a negative value gives the same result as a positive value, which means Newtonian mechanics cannot distinguish between the two directions of time. | |
| From: report of Isaac Newton (Principia Mathematica [1687]) by P Coveney / R Highfield - The Arrow of Time 2 'anatomy' | |
| A reaction: Maybe Newton just forgot to mention that negative values were excluded. (Or was he unaware of the sequence of negative integers?). Too late now - he's done it. |
| 17015 | If there is no uniform motion, we cannot exactly measure time [Newton] |
| Full Idea: It is possible that there is no uniform motion by which time may have an exact measure. All motions can be accelerated and retarded, but the flow of absolute time cannot be changed. | |
| From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol) |
| 17025 | If a perfect being does not rule the cosmos, it is not God [Newton] |
| Full Idea: A being, however perfect, without dominion is not the Lord God. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol) |
| 17024 | The elegance of the solar system requires a powerful intellect as designer [Newton] |
| Full Idea: This most elegant system of the sun, planets, and comets could not have arisen without the design and dominion of an intelligent and powerful being. | |
| From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol) |