111 ideas
| 19275 | You cannot understand what exists without understanding possibility and necessity [Hale] |
| 10308 | Questions about objects are questions about certain non-vacuous singular terms [Hale] |
| 19291 | A canonical defintion specifies the type of thing, and what distinguish this specimen [Hale] |
| 10314 | An expression is a genuine singular term if it resists elimination by paraphrase [Hale] |
| 19297 | The two Barcan principles are easily proved in fairly basic modal logic [Hale] |
| 19301 | With a negative free logic, we can dispense with the Barcan formulae [Hale] |
| 14239 | The empty set is usually derived from Separation, but it also seems to need Infinity [Oliver/Smiley] |
| 14240 | The empty set is something, not nothing! [Oliver/Smiley] |
| 14241 | We don't need the empty set to express non-existence, as there are other ways to do that [Oliver/Smiley] |
| 14242 | Maybe we can treat the empty set symbol as just meaning an empty term [Oliver/Smiley] |
| 14243 | The unit set may be needed to express intersections that leave a single member [Oliver/Smiley] |
| 19296 | If second-order variables range over sets, those are just objects; properties and relations aren't sets [Hale] |
| 19289 | Maybe conventionalism applies to meaning, but not to the truth of propositions expressed [Hale] |
| 10316 | We should decide whether singular terms are genuine by their usage [Hale] |
| 10312 | Often the same singular term does not ensure reliable inference [Hale] |
| 10313 | Plenty of clear examples have singular terms with no ontological commitment [Hale] |
| 10322 | If singular terms can't be language-neutral, then we face a relativity about their objects [Hale] |
| 14234 | If you only refer to objects one at a time, you need sets in order to refer to a plurality [Oliver/Smiley] |
| 14237 | We can use plural language to refer to the set theory domain, to avoid calling it a 'set' [Oliver/Smiley] |
| 19298 | Unlike axiom proofs, natural deduction proofs needn't focus on logical truths and theorems [Hale] |
| 14245 | Logical truths are true no matter what exists - but predicate calculus insists that something exists [Oliver/Smiley] |
| 10632 | The real numbers may be introduced by abstraction as ratios of quantities [Hale, by Hale/Wright] |
| 14246 | If mathematics purely concerned mathematical objects, there would be no applied mathematics [Oliver/Smiley] |
| 14247 | Sets might either represent the numbers, or be the numbers, or replace the numbers [Oliver/Smiley] |
| 19295 | Add Hume's principle to logic, to get numbers; arithmetic truths rest on the nature of the numbers [Hale] |
| 19281 | Interesting supervenience must characterise the base quite differently from what supervenes on it [Hale] |
| 10512 | The abstract/concrete distinction is based on what is perceivable, causal and located [Hale] |
| 10517 | Colours and points seem to be both concrete and abstract [Hale] |
| 10519 | The abstract/concrete distinction is in the relations in the identity-criteria of object-names [Hale] |
| 10520 | Token-letters and token-words are concrete objects, type-letters and type-words abstract [Hale] |
| 10524 | There is a hierarchy of abstraction, based on steps taken by equivalence relations [Hale] |
| 19278 | There is no gap between a fact that p, and it is true that p; so we only have the truth-condtions for p [Hale] |
| 10521 | If F can't have location, there is no problem of things having F in different locations [Hale] |
| 10511 | It is doubtful if one entity, a universal, can be picked out by both predicates and abstract nouns [Hale] |
| 10318 | Realists take universals to be the referrents of both adjectives and of nouns [Hale] |
| 10310 | Objections to Frege: abstracta are unknowable, non-independent, unstatable, unindividuated [Hale] |
| 10518 | Shapes and directions are of something, but games and musical compositions are not [Hale] |
| 10513 | Many abstract objects, such as chess, seem non-spatial, but are not atemporal [Hale] |
| 10514 | If the mental is non-spatial but temporal, then it must be classified as abstract [Hale] |
| 10523 | Being abstract is based on a relation between things which are spatially separated [Hale] |
| 10307 | The modern Fregean use of the term 'object' is much broader than the ordinary usage [Hale] |
| 10315 | We can't believe in a 'whereabouts' because we ask 'what kind of object is it?' [Hale] |
| 19302 | If a chair could be made of slightly different material, that could lead to big changes [Hale] |
| 10522 | The relations featured in criteria of identity are always equivalence relations [Hale] |
| 10321 | We sometimes apply identity without having a real criterion [Hale] |
| 15086 | Absolute necessity might be achievable either logically or metaphysically [Hale] |
| 19290 | Absolute necessities are necessarily necessary [Hale] |
| 8261 | Maybe not-p is logically possible, but p is metaphysically necessary, so the latter is not absolute [Hale] |
| 15081 | A strong necessity entails a weaker one, but not conversely; possibilities go the other way [Hale] |
| 15080 | 'Relative' necessity is just a logical consequence of some statements ('strong' if they are all true) [Hale] |
| 19286 | 'Absolute necessity' is when there is no restriction on the things which necessitate p [Hale] |
| 19288 | Logical and metaphysical necessities differ in their vocabulary, and their underlying entities [Hale] |
| 15082 | Metaphysical necessity says there is no possibility of falsehood [Hale] |
| 15085 | 'Broadly' logical necessities are derived (in a structure) entirely from the concepts [Hale] |
| 15088 | Logical necessities are true in virtue of the nature of all logical concepts [Hale] |
| 19285 | Logical necessity is something which is true, no matter what else is the case [Hale] |
| 19287 | Maybe each type of logic has its own necessity, gradually becoming broader [Hale] |
| 12432 | Explanation of necessity must rest on something necessary or something contingent [Hale] |
| 12434 | Why is this necessary, and what is necessity in general; why is this necessary truth true, and why necessary? [Hale] |
| 12435 | The explanation of a necessity can be by a truth (which may only happen to be a necessary truth) [Hale] |
| 19282 | It seems that we cannot show that modal facts depend on non-modal facts [Hale] |
| 12433 | If necessity rests on linguistic conventions, those are contingent, so there is no necessity [Hale] |
| 15087 | Conceptual necessities are made true by all concepts [Hale] |
| 12436 | Concept-identities explain how we know necessities, not why they are necessary [Hale] |
| 19276 | The big challenge for essentialist views of modality is things having necessary existence [Hale] |
| 19293 | Essentialism doesn't explain necessity reductively; it explains all necessities in terms of a few basic natures [Hale] |
| 19294 | If necessity derives from essences, how do we explain the necessary existence of essences? [Hale] |
| 19279 | What are these worlds, that being true in all of them makes something necessary? [Hale] |
| 19299 | Possible worlds make every proposition true or false, which endorses classical logic [Hale] |
| 4669 | Persons are conscious, they relate, they think, they feel, and they are self-aware [Glover] |
| 19300 | The molecules may explain the water, but they are not what 'water' means [Hale] |
| 4656 | A problem arises in any moral system that allows more than one absolute right [Glover] |
| 4657 | Double Effect: no bad acts with good consequences, but possibly good acts despite bad consequences [Glover] |
| 4658 | Acts and Omissions: bad consequences are morally better if they result from an omission rather than an act [Glover] |
| 4659 | It doesn't seem worse to switch off a life-support machine than to forget to switch it on [Glover] |
| 4660 | Harmful omissions are unavoidable, while most harmful acts can be avoided [Glover] |
| 4661 | What matters is not intrinsic value of life or rights, but worthwhile and desired life, and avoidance of pain [Glover] |
| 4648 | 'Death' is best seen as irreversible loss of consciousness, since this is why we care about brain function [Glover] |
| 3785 | You can't separate acts from the people performing them [Glover] |
| 3786 | Aggression in defence may be beneficial but morally corrupting [Glover] |
| 4650 | The quality of a life is not altogether independent of its length [Glover] |
| 3784 | Duty prohibits some acts, whatever their consequences [Glover] |
| 3782 | Satisfaction of desires is not at all the same as achieving happiness [Glover, by PG] |
| 3787 | Rule-utilitarianism is either act-utilitarianism, or not really utilitarian [Glover] |
| 3783 | How can utilitarianism decide the ideal population size? [Glover] |
| 4675 | The sanctity of life doctrine implies a serious increase of abnormality among the population [Glover] |
| 4654 | Autonomy favours present opinions over future ones, and says nothing about the interests of potential people [Glover] |
| 4655 | If a whole community did not mind death, respect for autonomy suggests that you could kill them all [Glover] |
| 4680 | Autonomy seems to acquire greater weight when the decision is more important to a person [Glover] |
| 4670 | Being alive is not intrinsically good, and there is no 'right to life' [Glover] |
| 4668 | You can't have a right to something you can't desire, so a foetus has no 'right' to life [Glover] |
| 4649 | If someone's life is 'worth living', that gives one direct reason not to kill him [Glover] |
| 4651 | Utilitarians object to killing directly (pain, and lost happiness), and to side-effects (loss to others, and precedents) [Glover] |
| 4671 | What is wrong with killing someone, if another equally worthwhile life is substituted? [Glover] |
| 4676 | The 'no trade-off' position: killing is only justified if it prevents other deaths [Glover] |
| 4685 | Societies spend a lot to save known persons, but very little to reduce fatal accidents [Glover] |
| 4683 | Involuntary euthanasia is wrong because it violates autonomy, and it has appalling side-effects [Glover] |
| 4682 | Euthanasia is voluntary (patient's wish), or involuntary (ignore wish), or non-voluntary (no wish possible) [Glover] |
| 4684 | Maybe extreme treatment is not saving life, but prolonging the act of dying [Glover] |
| 4681 | The Nazi mass murders seem to have originated in their euthanasia programme [Glover] |
| 4667 | How would we judge abortion if mothers had transparent wombs? [Glover] |
| 4665 | Conception isn't the fixed boundary for a person's beginning, because twins are possible within two weeks [Glover] |
| 4652 | If killing is wrong because it destroys future happiness, not conceiving a happy child is also wrong [Glover] |
| 4662 | Defenders of abortion focus on early pregnancy, while opponents focus on later stages [Glover] |
| 4663 | If abortion is wrong, it is because a foetus is a human being or a person (or potentially so) [Glover] |
| 4664 | If abortion is wrong because of the 'potential' person, that makes contraception wrong too [Glover] |
| 4673 | Abortion differs morally from deliberate non-conception only in its side-effects [Glover] |
| 4666 | If viability is a test or boundary at the beginning of life, it should also be so for frail old people [Glover] |
| 4672 | Apart from side effects, it seems best to replace an inadequate foetus with one which has a better chance [Glover] |
| 4674 | It is always right for a qualified person to perform an abortion when requested by the mother [Glover] |
| 4679 | One test for a worthwhile life is to assess the amount of life for which you would rather be unconscious [Glover] |