44 ideas
| 14684 | A world is 'accessible' to another iff the first is possible according to the second [Salmon,N] |
| Full Idea: A world w' is accessible to a consistent world w if and only if w' is possible in w. Being 'inaccessible to' or 'possible relative to' a consistent world is simply being possible according to that world, nothing more and nothing less. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
| A reaction: More illuminating than just saying that w can 'see' w'. Accessibility is internal to worIds. It gives some connection to why we spend time examining modal logic. There is no more important metaphysical notion than what is possible according to actuality. |
| 14669 | For metaphysics, T may be the only correct system of modal logic [Salmon,N] |
| Full Idea: Insofar as modal logic is concerned exclusively with the logic of metaphysical modality, ..T may well be the one and only (strongest) correct system of (first-order) propositional logic. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro) | |
| A reaction: This contrasts sharply with the orthodox view, that S5 (or at the very least S4) is the correct system for metaphysics. |
| 14692 | System B implies that possibly-being-realized is an essential property of the world [Salmon,N] |
| Full Idea: Friends of B modal logic commit themselves to the loaded claim that it is logically true that the property of possibly being realized (or being a way things might have been) is an essential property of the world. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], V) | |
| A reaction: I think this 'loaded' formulation captures quite nicely the dispositional view I favour, that the possibilities of the actual world are built into the actual world, and define its nature just as much as the 'categorial' facts do. |
| 14667 | System B has not been justified as fallacy-free for reasoning on what might have been [Salmon,N] |
| Full Idea: Even the conventionally accepted system B, which is weaker than S5 and independent of S4, has not been adequately justified as a fallacy-free system of reasoning about what might have been. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro) |
| 14668 | In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N] |
| Full Idea: The characteristic of B has the form φ⊃□◊φ. ...Even if these axioms are necessarily true, it seems logically possible for p to be true while the proposition that p is necessarily possible is at the same time false. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro) |
| 14671 | What is necessary is not always necessarily necessary, so S4 is fallacious [Salmon,N] |
| Full Idea: We can say of a wooden table that it would have been possible for it to have originated from some different matter, even though it is not actually possible. So what is necessary fails to be necessarily necessary, and S4 modal logic is fallacious. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], I) | |
| A reaction: [compressed] |
| 14686 | S5 modal logic ignores accessibility altogether [Salmon,N] |
| Full Idea: When we ignore accessibility altogether, we have finally zeroed in on S5 modal logic. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) |
| 14691 | S5 believers say that-things-might-have-been-that-way is essential to ways things might have been [Salmon,N] |
| Full Idea: Believers in S5 as a correct system of propositional reasoning about what might have been must claim that it is an essential property of any way things might have been that things might have been that way. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], V) | |
| A reaction: Salmon is working in a view where you are probably safe to substitute 'necessary' for 'essential' without loss of meaning. |
| 14693 | The unsatisfactory counterpart-theory allows the retention of S5 [Salmon,N] |
| Full Idea: Counterpart-theoretic modal semantics allows for the retention of S5 modal propositional logic, at a considerable cost. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], V n18) | |
| A reaction: See the other ideas in this paper by Salmon for his general attack on S5 as the appropriate system for metaphysical necessity. He favours the very modest System T. |
| 14670 | Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..) [Salmon,N] |
| Full Idea: Metaphysical modal logic concerns metaphysical (or alethic) necessity and metaphysical (alethic) possibility, or necessity and possibility tout court - as opposed to such other types of modality as physical necessity, epistemic necessity etc. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro n2) |
| 14678 | Any property is attached to anything in some possible world, so I am a radical anti-essentialist [Salmon,N] |
| Full Idea: By admitting possible worlds of unlimited variation and recombination, I simply abandon true metaphysical essentialism. By my lights, any property is attached to anything in some possible world or other. I am a closet radical anti-essentialist. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], II) | |
| A reaction: Salmon includes impossible worlds within his scheme of understanding. It strikes me that this is metaphysical system which tells us nothing about how things are: it is sort of 'logical idealist'. Later he talks of 'we essentialists'. |
| 14680 | Logical possibility contains metaphysical possibility, which contains nomological possibility [Salmon,N] |
| Full Idea: Just as nomological possibility is a special kind of metaphysical possibility, so metaphysical possibility is a special kind of logical possibility. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
| A reaction: This is the standard view of how the three types of necessity are nested. He gives a possible counterexample in footnote 7. |
| 14685 | Metaphysical necessity is NOT truth in all (unrestricted) worlds; necessity comes first, and is restricted [Salmon,N] |
| Full Idea: A mythology gave us the idea that metaphysical necessity is truth in every world whatsoever, without restriction. But the notion of metaphysical modality comes first, and, like every notion of modality, it is restricted. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) |
| 14690 | In the S5 account, nested modalities may be unseen, but they are still there [Salmon,N] |
| Full Idea: The S5 theorist's miscontrual of English (in the meaning of 'possibly possible') makes nested modality unseen, but it does not make nested modality vanish. Inaccessible worlds are still worlds. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) |
| 14688 | Without impossible worlds, the unrestricted modality that is metaphysical has S5 logic [Salmon,N] |
| Full Idea: If one confines one's sights to genuinely possible worlds, disavowing the impossible worlds, then metaphysical modality emerges as the limiting case - the 'unrestricted' modality that takes account of 'every' world - and S5 emerges as its proper logic. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
| A reaction: He observes that this makes metaphysical modality 'restricted' simply because you have restricted what 'all worlds' means. Could there be non-maximal worlds? Are logical and metaphysical modality coextensive? I think I like the S5 view. |
| 14677 | Metaphysical necessity is said to be unrestricted necessity, true in every world whatsoever [Salmon,N] |
| Full Idea: It is held that it is the hallmark of metaphysical necessity is that it is completely unrestricted, the limiting case of restricted necessity, with no restrictions whatever. A proposition is necessary only if it is true in absolutely every world whatever. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], II) | |
| A reaction: This is the standard picture which leads to the claim that S5 modal logic is appropriate for metaphysical necessity, because there are no restrictions on accessibility. Salmon raises objections to this conventional view. |
| 14679 | Bizarre identities are logically but not metaphysically possible, so metaphysical modality is restricted [Salmon,N] |
| Full Idea: Though there is a way things logically could be according to which I am a credit card account, there is no way things metaphysically might be according to which I am a credit card account. This illustrates the restricted nature of metaphysical modality. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
| A reaction: His drift is that metaphyical modality is restricted, but expressing it in S5 modal logic (where all worlds see one another) makes it unrestricted, so S5 logic is wrong for metaphysics. I'm impressed by his arguments. |
| 14681 | Logical necessity is free of constraints, and may accommodate all of S5 logic [Salmon,N] |
| Full Idea: With its freedom from the constraint of metaphysical possibility, logical necessity may be construed as accommodating all the axioms and rules of S5. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
| A reaction: He goes on to raise problems for this simple thought. The big question: what are the limits of what is actually possible? Compare: what are the limits of what is imaginable? what are the limits of what is meaningfully sayable? |
| 14676 | Nomological necessity is expressed with intransitive relations in modal semantics [Salmon,N] |
| Full Idea: Intransitive relations are introduced into modal semantics for the purposes of interpreting various 'real' or restricted types of modalities, such as nomological necessity. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], II) | |
| A reaction: The point here is that the (so-called) 'laws of nature' are held to change from world to world, so necessity in one could peter out in some more remote world, rather than being carried over everywhere. A very Humean view of such things. |
| 14689 | Necessity and possibility are not just necessity and possibility according to the actual world [Salmon,N] |
| Full Idea: The real meanings of the simple modal terms 'necessary' and 'possible' are not the same as the concepts of actual necessity and actual possibility, necessity and possibility according to the actual world. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
| A reaction: If you were an 'actualist' (who denies everything except the actual world) then you are unlikely to agree with this. In unrestricted possible worlds, being true in one world makes it possible in all worlds. So actual necessity is possible everywhere. |
| 14674 | Impossible worlds are also ways for things to be [Salmon,N] |
| Full Idea: Total ways things cannot be are also 'worlds', or maximal ways for things to be. They are impossible worlds. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], I) | |
| A reaction: This unorthodox view doesn't sound too plausible to me. To think of a circular square as a 'way things could be' sounds pretty empty, and mere playing with words. The number 7 could be the Emperor of China? |
| 14682 | Denial of impossible worlds involves two different confusions [Salmon,N] |
| Full Idea: Every argument I am aware of against impossible worlds confuses ways for things to be with ways things might have been, or worse, confuses ways things cannot be with ways for things to be that cannot exist - or worse yet, commits both errors. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
| A reaction: He is claiming that 'ways for things to be' allows impossible worlds, whereas 'ways things might have been' appears not to. (I think! Read the paragraph yourself!) |
| 14687 | Without impossible worlds, how things might have been is the only way for things to be [Salmon,N] |
| Full Idea: If one ignores impossible worlds, then ways things might have been are the only ways for things to be that are left. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
| A reaction: Impossible worlds are included in 'ways for things to be', but excluded from 'ways things might have been'. I struggle with a circle being square as a 'way for circles to be'. I suppose being the greatest philosopher is a way for me to be. |
| 14683 | Possible worlds rely on what might have been, so they can' be used to define or analyse modality [Salmon,N] |
| Full Idea: On my conception, the notions of metaphysical necessity and possibility are not defined or analyzed in terms of the apparatus of possible worlds. The order of analysis is just the reverse: possible worlds rely on the notion of what might have been. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
| A reaction: This view seems to be becoming the new orthodoxy, and I certainly agree with it. I have no idea how you can begin to talk about possible worlds if you don't already have some idea of what 'possible' means. |
| 14675 | Possible worlds just have to be 'maximal', but they don't have to be consistent [Salmon,N] |
| Full Idea: As far as I can tell, worlds need not be logically consistent. The only restriction on worlds is that they must be (in some sense) 'maximal' ways for things to be. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], I) | |
| A reaction: The normal idea of a maximal model is that it must contain either p or ¬p, and not both, so I don't think I understand this thought, but I pass it on. |
| 14672 | Possible worlds are maximal abstract ways that things might have been [Salmon,N] |
| Full Idea: I conceive of possible worlds as certain sorts of maximal abstract entities according to which certain things (facts, states of affairs) obtain and certain other things do not obtain. They are total ways things might have been. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], I) |
| 14673 | You can't define worlds as sets of propositions, and then define propositions using worlds [Salmon,N] |
| Full Idea: It is not a good idea to think of possible worlds as sets of propositions, and at the same time to think of propositions as sets of possible worlds. | |
| From: Nathan Salmon (The Logic of What Might Have Been [1989], I n3) | |
| A reaction: Salmon favours thinking of worlds as sets of propositions, and hence rejects the account of propositions as sets of worlds. He favours the 'Russellian' view of propositions, which seem to me to be the same as 'facts'. |
| 7337 | In Mosaic legal theory, crimes are sins and sins are crimes [Johnson,P] |
| Full Idea: In Mosaic legal theory, all breaches of the law offend God. All crimes are sins, just as all sins are crimes. | |
| From: Paul Johnson (The History of the Jews [1987], Pt I) | |
| A reaction: This would seem to define Josephus called a 'theocracy'. Not just rule by a priesthood, but also an attempt to make civil law coincide with the teachings of sacred texts. But doing 80 m.p.h. on a motorway at 2 a.m. hardly seems like a sin. |
| 7339 | Because human life is what is sacred, Mosaic law has no death penalty for property violations [Johnson,P] |
| Full Idea: Where other codes provided the death penalty for offences against property, in Mosaic law no property offence is capital; human life is too sacred, where the rights of property alone are violated. | |
| From: Paul Johnson (The History of the Jews [1987], Pt I) | |
| A reaction: We still preserve this idea in our law, and also in our culture, where we are keen to insist that catastrophes like earthquakes or major fires are measured almost entirely by the loss of life, not the loss of property. I approve. |
| 7353 | The Pharisees undermined slavery, by giving slaves responsibility and status in law courts [Johnson,P] |
| Full Idea: It is no accident that slavery among Jews disappeared with the rise of the Pharisees, as they insisted that all were equal before God in a court. Masters were no longer responsible for actions of slaves, so a slave had status, and slavery could not work. | |
| From: Paul Johnson (The History of the Jews [1987], Pt II) | |
| A reaction: As in seventeenth century England, the rise of social freedom comes from religious sources, not social sources. A slave has status in the transcendent world of souls, despite being a nobody in the physical world. |
| 7340 | Mosaic law was the first to embody the rule of law, and equality before the law [Johnson,P] |
| Full Idea: Mosaic law meant that God ruled through his laws, and since all were equally subject to the law, the system was the first to embody the double merits of the rule of law and equality before the law. | |
| From: Paul Johnson (The History of the Jews [1987], Pt I) | |
| A reaction: If this is correct, it seems to be a hugely important step, combined with Idea 1659, that revenge should be the action of a the state, not of the individual. They are the few simple and essential keys to civilization. |
| 7338 | Man's life is sacred, because it is made in God's image [Johnson,P] |
| Full Idea: In Mosaic theology, man is made in God's image, and so his life is not just valuable, it is sacred. | |
| From: Paul Johnson (The History of the Jews [1987], Pt I) | |
| A reaction: The obvious question is what exactly is meant by "in God's image". Physically, spiritually, intellectually, morally? I am guessing that the original idea was intellectual, because we are the only rational animal. The others seem unlikely, or arrogant. |
| 5994 | Is the cosmos open or closed, mechanical or teleological, alive or inanimate, and created or eternal? [Robinson,TM, by PG] |
| Full Idea: The four major disputes in classical cosmology were whether the cosmos is 'open' or 'closed', whether it is explained mechanistically or teleologically, whether it is alive or mere matter, and whether or not it has a beginning. | |
| From: report of T.M. Robinson (Classical Cosmology (frags) [1997]) by PG - Db (ideas) | |
| A reaction: A nice summary. The standard modern view is closed, mechanistic, inanimate and non-eternal. But philosophers can ask deeper questions than physicists, and I say we are entitled to speculate when the evidence runs out. |
| 7348 | The Jews sharply distinguish human and divine, but the Greeks pull them closer together [Johnson,P] |
| Full Idea: The Jews drew an absolute distinction between the human and the divine; the Greeks constantly elevated the human - they were Promethean - and lowered the divine. | |
| From: Paul Johnson (The History of the Jews [1987], Pt II) | |
| A reaction: An intriguing observation. The Greek idea runs right through European culture, surfacing (for example) in 'Faust', or 'Frankenstein', or the films of James Cameron. I'm with the Greeks; I want to see how far humanity can be elevated. |
| 7355 | The Torah pre-existed creation, and was its blueprint [Johnson,P] |
| Full Idea: The Torah was not just a book about God. It pre-existed creation, in the same way as God did. In fact, it was the blueprint of creation. | |
| From: Paul Johnson (The History of the Jews [1987], Pt III) | |
| A reaction: You can only become a 'people of the book' (which Moslems resented in Judaism, and then emulated) if you give this stupendously high status to your book. Hence Christian fundamentalism makes sense, with its emphasis on the divinity of the Bible. |
| 7336 | A key moment is the idea of a single moral God, who imposes his morality on humanity [Johnson,P] |
| Full Idea: The discovery of monotheism, and not just of monotheism but of a sole, omnipotent God actuated by ethical principles and seeking methodically to impose them on human beings, is one of the greatest turning-points in history, perhaps the greatest of all. | |
| From: Paul Johnson (The History of the Jews [1987], Pt I) | |
| A reaction: 'Discovery' begs some questions, but when put like this you realise what a remarkable event it was. It is a good candidate for the most influential idea ever, even if large chunks of humanity, especially in the orient, never took to monotheism. |
| 7341 | Sampson illustrates the idea that religious heroes often begin as outlaws and semi-criminals [Johnson,P] |
| Full Idea: Sampson is the outstanding example of the point which the Book of Judges makes again and again, that the Lord and society are often served by semi-criminal types, outlaws and misfits, who become folk-heroes and then religious heroes. | |
| From: Paul Johnson (The History of the Jews [1987], Pt I) | |
| A reaction: This illustrates nicely Nietzsche's claim, that the jews were responsible for his 'inversion of values', in which aristocratic virtues are downgraded, and the virtues of a good slave are elevated (though Sampson may not show that point so well!). |
| 7342 | Isaiah moved Israelite religion away from the local, onto a more universal plane [Johnson,P] |
| Full Idea: The works of Isaiah (740-700 BCE) mark the point at which the Israelite religion began to spiritualize itself, to move from a specific location in space and time on to the universalist plane. | |
| From: Paul Johnson (The History of the Jews [1987], Pt I) | |
| A reaction: This is necessary if any religion is going to make converts outside the local culture. The crucial step would be to disembody God, so that He cannot be represented by a statue. The difficulty is for him to be universal, but retain a 'chosen people'. |
| 7344 | Judaism involves circumcision, Sabbath, Passover, Pentecost, Tabernacles, New Year, and Atonement [Johnson,P] |
| Full Idea: The practices of Judaism developed during their Exile: circumcision, the Sabbath, the Passover (founding of the nation), Pentecost (giving of the laws), the Tabernacles, the New Year, and the Day of Atonement. | |
| From: Paul Johnson (The History of the Jews [1987], Pt II) | |
| A reaction: These were the elements of ritual created to replace the existence of a physically located state. An astonishing achievement, not even remotely achieved by any other state that was driven off its lands. A culture is an idea, not a country. |
| 7345 | In exile the Jews became a nomocracy [Johnson,P] |
| Full Idea: In exile the Jews, deprived of a state, became a nomocracy - voluntarily submitting to rule by a Law which could only be enforced by consent. Nothing like this had occurred before in history. | |
| From: Paul Johnson (The History of the Jews [1987], Pt II) | |
| A reaction: It is the most remarkable case in history of a people united and strengthened by adversity, and it became an important experiment in the building of human cultures. But what is the point of preserving a culture, with no land? Why not just integrate? |
| 7347 | Zoroastrians believed in one eternal beneficent being, Creator through the holy spirit [Johnson,P] |
| Full Idea: Cyrus the Great was a Zoroastrian, believing in one, eternal, beneficent being, 'Creator of all things through the holy spirit'. | |
| From: Paul Johnson (The History of the Jews [1987], Pt II) | |
| A reaction: Is this the actual origin of monotheism, or did they absorb this idea from the Jews? The interesting bit is the fact that the supreme being (called Marduk) is 'beneficent', which one doesn't associate with these remote and supposed pagans. |
| 7349 | Immortality based on judgement of merit was developed by the Egyptians (not the Jews) [Johnson,P] |
| Full Idea: The idea of judgement at death and immortality on the basis of merit were developed in Egypt before 1000 BCE. It is not Jewish because it was not in the Torah, and the Sadducees, who stuck to their texts, seemed to have denied the afterlife completely. | |
| From: Paul Johnson (The History of the Jews [1987], Pt II) | |
| A reaction: This is the idea considered crucial to religion by Immanuel Kant (Idea 1455), who should be declared an honorary Egyptian. To me the idea that only the good go to heaven sounds like sadly wishful thinking - a fictional consolation for an unhappy life. |
| 7354 | The main doctrine of the Pharisees was belief in resurrection and the afterlife [Johnson,P] |
| Full Idea: Belief in resurrection and the afterlife was the main distinguishing mark of Pharisaism, and thus fundamental of rabbinic Judaism. | |
| From: Paul Johnson (The History of the Jews [1987], Pt II) | |
| A reaction: Belief in an afterlife seems to go back to the Egyptians, but this development in Judaism was obviously very influential, even among early Christians, who initially seem to have only believed in resurrection of the body. |
| 7356 | Pious Jews saw heaven as a vast library [Johnson,P] |
| Full Idea: Pious Jews saw heaven as a vast library, with the Archangel Metatron as the librarian: the books in the shelves there pressed themselves together to make room for a newcomer. | |
| From: Paul Johnson (The History of the Jews [1987], Pt III) | |
| A reaction: I'm tempted to convert to Judaism. |