24 ideas
15375 | If terms change their designations in different states, they are functions from states to objects [Fitting] |
Full Idea: The common feature of every designating term is that designation may change from state to state - thus it can be formalized by a function from states to objects. | |
From: Melvin Fitting (Intensional Logic [2007], 3) | |
A reaction: Specifying the objects sounds OK, but specifying states sounds rather tough. |
15376 | Intensional logic adds a second type of quantification, over intensional objects, or individual concepts [Fitting] |
Full Idea: To first order modal logic (with quantification over objects) we can add a second kind of quantification, over intensions. An intensional object, or individual concept, will be modelled by a function from states to objects. | |
From: Melvin Fitting (Intensional Logic [2007], 3.3) |
15378 | Awareness logic adds the restriction of an awareness function to epistemic logic [Fitting] |
Full Idea: Awareness logic enriched Hintikka's epistemic models with an awareness function, mapping each state to the set of formulas we are aware of at that state. This reflects some bound on the resources we can bring to bear. | |
From: Melvin Fitting (Intensional Logic [2007], 3.6.1) | |
A reaction: [He cites Fagin and Halpern 1988 for this] |
15379 | Justication logics make explicit the reasons for mathematical truth in proofs [Fitting] |
Full Idea: In justification logics, the logics of knowledge are extended by making reasons explicit. A logic of proof terms was created, with a semantics. In this, mathematical truths are known for explicit reasons, and these provide a measure of complexity. | |
From: Melvin Fitting (Intensional Logic [2007], 3.6.1) |
11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
Full Idea: Mathematics is typically extensional throughout (we write 3+2=2+3 despite the two terms having different meanings). ..Classical first-order logic is extensional by design since it primarily evolved to model the reasoning of mathematics. | |
From: Melvin Fitting (Intensional Logic [2007], §1) |
11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
Full Idea: λ-abstraction can be used to abstract and disambiguate a predicate. De re is [λx◊P(x)](f) - f has the possible-P property - and de dicto is ◊[λxP(x)](f) - possibly f has the P-property. Also applies to □. | |
From: Melvin Fitting (Intensional Logic [2007], §3.3) | |
A reaction: Compare the Barcan formula. Originated with Church in the 1930s, and Carnap 1947, but revived by Stalnaker and Thomason 1968. Because it refers to the predicate, it has a role in intensional versions of logic, especially modal logic. |
1212 | Replacing timbers on Theseus' ship was the classic illustration of the problem of growth and change [Plutarch] |
Full Idea: At intervals they removed old timbers from the preserved ship and replaced them with sound ones, so the ship became a classic illustration for the philosophers of the disputed question of growth and change, some saying it was the same, others different. | |
From: Plutarch (Life of Theseus [c.85], 23) |
15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |
Full Idea: Definite descriptions pick out different objects in different possible worlds quite naturally. | |
From: Melvin Fitting (Intensional Logic [2007], 3.4) | |
A reaction: A definite description can pick out the same object in another possible world, or a very similar one, or an object which has almost nothing in common with the others. |
5958 | The sun is always bright; it doesn't become bright when it emerges [Plutarch] |
Full Idea: The sun doesn't become bright when it emerges from the clouds; it always is bright. | |
From: Plutarch (26: Oracles in Decline [c.85], §39) | |
A reaction: Not an argument, but a nice appeal to common sense, like Russell's example of the cat that disappears behind the furniture and then reappears. To disagree with Plutarch here strikes me as the road to philosophical absurdity. |
5959 | Some philosophers say the soul is light [Plutarch] |
Full Idea: Some philosophers hold that the soul is in its essence light. | |
From: Plutarch (75: Is 'Live Unknown' a Wise Precept? [c.85], §6) | |
A reaction: A nice idea, to rival the stoic view that the soul is fire. It is understandable to propose that the soul is some sort of lightweight and fast moving matter. How else could thought be achieved physically? Nowadays, parallel processing is our only model. |
5960 | When the soul is intelligent and harmonious, it is part of god and derives from god [Plutarch] |
Full Idea: The soul, when it has partaken of intelligence and reason and concord, is not merely a work but also a part of god and has come to be not by his agency but both from him as source and out of his substance. | |
From: Plutarch (67: Platonic Questions [c.85], II.1001) | |
A reaction: A most intriguing shift of view from earlier concepts of the psuché. How did this come about? This man is a pagan. The history is in the evolution of Platonism. See 'The Middle Platonists' by John Dillon. Davidson is also very impressed by reason. |
5952 | Rather than being the whole soul, maybe I am its chief part? [Plutarch] |
Full Idea: Is each of us not the soul, but the chief part of the soul, by which we think and reason and act, all the other parts of soul as well as of body being mere instruments of its power? | |
From: Plutarch (74: Reply to Colotes [c.85], §1119) | |
A reaction: Socrates is associated with the idea that I am my whole soul (Idea 1650). Plutarch represents an interesting development, which may lead both to the Christian 'soul' and to the Cartesian 'ego'. I think Plutarch is right, but what is the 'soul'? |
5951 | If atoms have no qualities, they cannot possibly produce a mind [Plutarch] |
Full Idea: Perception, mind, intelligence and thought cannot so much as be conceived, even with the best will, as arising among void and atoms, things which taken separately have no quality. | |
From: Plutarch (74: Reply to Colotes [c.85], §1112) | |
A reaction: A nice articulation of the intuition of all anti-physicalists. Plutarch would have to rethink his position carefully if he learned of the sheer number of connections in the brain, and of the theory of natural selection. His challenge remains, though. |
5963 | Some say emotion is a sort of reason, and others say virtue concerns emotion [Plutarch] |
Full Idea: Some philosophers make the emotions varieties of reason, on the ground that all desire and grief and anger are judgments, while others declare that the virtues have to do with emotions, as when fear is the province of courage. | |
From: Plutarch (68: Generation of the soul in 'Timaeus' [c.85], 1025d) | |
A reaction: The second idea comes from Aristotle, but the second is interesting, and corresponds to the views coming from modern neuroscience, where even the most basic thought seems to involve emotion. What could be the motivation for 'pure' reason? |
20796 | Action needs an affinity for a presentation, and an impulse toward the affinity [Plutarch] |
Full Idea: The sceptics say there are three movements of the soul: presentation, impulse and assent. …And action requires two things: a presentation of something to which one has an affinity, and an impulse toward what is presented as an object of affinity. | |
From: Plutarch (74: Reply to Colotes [c.85], 1122c) | |
A reaction: Not much reasoning involved in this account, which the sceptics say is compatible with suspension of judgement. |
1477 | Being manly and brave is the result of convention, not of human nature [Plutarch] |
Full Idea: Manliness is not a natural human attribute, otherwise women would be just as brave. It is due to pressure from laws, and this pressure has no free will, but is a slave of convention and criticism. | |
From: Plutarch (64: Gryllus - on Rationality in Animals [c.85], 988c) | |
A reaction: This is the first glimmerings of seeing gender as a cultural creation, rather than as a fact. Presumably he takes the same view of some of the supposed feminine virtues. |
1478 | Animals don't value pleasure, as they cease sexual intercourse after impregnation [Plutarch] |
Full Idea: Animals of both sexes cease to have intercourse after impregnation; that shows how little animals value pleasure, and that nature is all that counts. | |
From: Plutarch (64: Gryllus - on Rationality in Animals [c.85], 990d) | |
A reaction: A famous monkey had an implant to stimulate pleasure, and a button to trigger it. It apparently would have starved to death rather than release the button. Animal sex is dull? |
5948 | The good life involves social participation, loyalty, temperance and honesty [Plutarch] |
Full Idea: To live the good life is to live a life of participation in society, of loyalty to friends, of temperance and honest dealing. | |
From: Plutarch (74: Reply to Colotes [c.85], §1108) | |
A reaction: 'Participation in society' is the interesting one. This might translate as 'doing your duty', or as 'leading a well-rounded life'. Solitude is wrong if you are indebted to others, and it is unhealthy if you are not. Is solitude really immoral, though? |
1479 | Animals have not been led into homosexuality, because they value pleasure very little [Plutarch] |
Full Idea: Because animals value pleasure very little, they have not been led into sex between males or between females. | |
From: Plutarch (64: Gryllus - on Rationality in Animals [c.85], 990d) |
6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |
Full Idea: Hermarchus said that animal killing is justified by considerations of human safety and nourishment and by animals' inability to form contractual relations of justice with us. | |
From: report of Hermarchus (fragments/reports [c.270 BCE]) by David A. Sedley - Hermarchus | |
A reaction: Could the last argument be used to justify torturing animals? Or could we eat a human who was too brain-damaged to form contracts? |
5950 | If only atoms exist, how do qualities arise when the atoms come together? [Plutarch] |
Full Idea: If you accept atomism, you must show how bodies without quality have given rise to qualities of every kind by the mere fact of coming together. For example, how has the quality called 'hot' been imposed on the atoms? | |
From: Plutarch (74: Reply to Colotes [c.85], §1111) | |
A reaction: This argument is still significant in current philosophy of mind. If temperature is 'mean kinetic energy', you are left wondering where the energy came from, and why minds experience the heat. This is the 'Hard Question'. |
5974 | People report seeing through rocks, or over the horizon, or impossibly small works [Plutarch] |
Full Idea: It is said that Lynceus could see through rock and tree, and a lookout in Sicily saw Carthaginian ships a day and a half away, and Callicrates and Myrmecides are said to fashion carriages canopied with the wings of fly, and write on sesame seeds. | |
From: Plutarch (72: Against Stoics on common Conceptions [c.85], 1083e) | |
A reaction: A warning from Plutarch against believing everything you hear! |
5957 | Absurd superstitions make people atheist, not disharmony in nature [Plutarch] |
Full Idea: Men have never thought the universe godless on the ground of detecting some fault in stars or seasons; ..it is the ridiculous things that superstition does that makes people say it would be better if there were no gods at all. | |
From: Plutarch (14: Superstition [c.85], §12) | |
A reaction: Not true, I would say. Absurd superstitions do discredit belief in the supernatural, but earthquakes are a disharmony in nature, and a nasty one at that. Nowadays we have other explanations to rival those of religion. |
5955 | No one will ever find a city that lacks religious practices [Plutarch] |
Full Idea: A city without holy places and gods, without any observance of prayers, oaths, oracles, sacrifices for blessings received or rites to avert evils, no traveller has ever seen or will ever see. | |
From: Plutarch (74: Reply to Colotes [c.85], §1125) | |
A reaction: The nearest you might get would be Soviet Moscow, but in 1973 I saw a man there jeering at a woman who was kneeling in the street outside a closed church. Plutarch would be stunned at the decline in religious practices in modern Europe. |