48 ideas
| 7823 | Lucretius was rediscovered in 1417 [Grayling] |
| Full Idea: Lucretius's 'De Rerum Natura' was rediscovered in 1417, after languishing forgotten for six centuries. | |
| From: A.C. Grayling (What is Good? [2003], Ch.5) | |
| A reaction: A wonder. Is it the greatest book of the ancient world - because it partially preserves the lost philosophy of great Democritus? |
| 17713 | After 1903, Husserl avoids metaphysical commitments [Mares] |
| Full Idea: In Husserl's philosophy after 1903, he is unwilling to commit himself to any specific metaphysical views. | |
| From: Edwin D. Mares (A Priori [2011], 08.2) |
| 18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
| Full Idea: We are able to reason about inconsistent beliefs, stories, and theories in useful and important ways | |
| From: Edwin D. Mares (Negation [2014], 1) |
| 18789 | Intuitionist logic looks best as natural deduction [Mares] |
| Full Idea: Intuitionist logic appears most attractive in the form of a natural deduction system. | |
| From: Edwin D. Mares (Negation [2014], 5.5) |
| 18790 | Intuitionism as natural deduction has no rule for negation [Mares] |
| Full Idea: In intuitionist logic each connective has one introduction and one elimination rule attached to it, but in the classical system we have to add an extra rule for negation. | |
| From: Edwin D. Mares (Negation [2014], 5.5) | |
| A reaction: How very intriguing. Mares says there are other ways to achieve classical logic, but they all seem rather cumbersome. |
| 18787 | Three-valued logic is useful for a theory of presupposition [Mares] |
| Full Idea: One reason for wanting a three-valued logic is to act as a basis of a theory of presupposition. | |
| From: Edwin D. Mares (Negation [2014], 3.1) | |
| A reaction: [He cites Strawson 1950] The point is that you can get a result when the presupposition does not apply, as in talk of the 'present King of France'. |
| 18793 | Material implication (and classical logic) considers nothing but truth values for implications [Mares] |
| Full Idea: The problem with material implication, and classical logic more generally, is that it considers only the truth value of formulas in deciding whether to make an implication stand between them. It ignores everything else. | |
| From: Edwin D. Mares (Negation [2014], 7.1) | |
| A reaction: The obvious problem case is conditionals, and relevance is an obvious extra principle that comes to mind. |
| 18784 | In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares] |
| Full Idea: Among the virtues of classical logic is the fact that the connectives are related to one another in elegant ways that often involved negation. For example, De Morgan's Laws, which involve negation, disjunction and conjunction. | |
| From: Edwin D. Mares (Negation [2014], 2.2) | |
| A reaction: Mares says these enable us to take disjunction or conjunction as primitive, and then define one in terms of the other, using negation as the tool. |
| 18786 | Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares] |
| Full Idea: On its standard reading, excluded middle tells us that bivalence holds. To reject excluded middle, we must reject either non-contradiction, or ¬(A∧B) ↔ (¬A∨¬B) [De Morgan 3], or the principle of double negation. All have been tried. | |
| From: Edwin D. Mares (Negation [2014], 2.2) |
| 18780 | Standard disjunction and negation force us to accept the principle of bivalence [Mares] |
| Full Idea: If we treat disjunction in the standard way and take the negation of a statement A to mean that A is false, accepting excluded middle forces us also to accept the principle of bivalence, which is the dictum that every statement is either true or false. | |
| From: Edwin D. Mares (Negation [2014], 1) | |
| A reaction: Mates's point is to show that passively taking the normal account of negation for granted has important implications. |
| 18782 | The connectives are studied either through model theory or through proof theory [Mares] |
| Full Idea: In studying the logical connectives, philosophers of logic typically adopt the perspective of either model theory (givng truth conditions of various parts of the language), or of proof theory (where use in a proof system gives the connective's meaning). | |
| From: Edwin D. Mares (Negation [2014], 1) | |
| A reaction: [compressed] The commonest proof theory is natural deduction, giving rules for introduction and elimination. Mates suggests moving between the two views is illuminating. |
| 18783 | Many-valued logics lack a natural deduction system [Mares] |
| Full Idea: Many-valued logics do not have reasonable natural deduction systems. | |
| From: Edwin D. Mares (Negation [2014], 1) |
| 18792 | Situation semantics for logics: not possible worlds, but information in situations [Mares] |
| Full Idea: Situation semantics for logics consider not what is true in worlds, but what information is contained in situations. | |
| From: Edwin D. Mares (Negation [2014], 6.2) | |
| A reaction: Since many theoretical physicists seem to think that 'information' might be the most basic concept of a natural ontology, this proposal is obviously rather appealing. Barwise and Perry are the authors of the theory. |
| 18785 | Consistency is semantic, but non-contradiction is syntactic [Mares] |
| Full Idea: The difference between the principle of consistency and the principle of non-contradiction is that the former must be stated in a semantic metalanguage, whereas the latter is a thesis of logical systems. | |
| From: Edwin D. Mares (Negation [2014], 2.2) |
| 17715 | The truth of the axioms doesn't matter for pure mathematics, but it does for applied [Mares] |
| Full Idea: The epistemological burden of showing that the axioms are true is removed if we are only studying pure mathematics. If, however, we want to look at applied mathematics, then this burden returns. | |
| From: Edwin D. Mares (A Priori [2011], 11.4) | |
| A reaction: One of those really simple ideas that hits the spot. Nice. The most advanced applied mathematics must rest on counting and measuring. |
| 17716 | Mathematics is relations between properties we abstract from experience [Mares] |
| Full Idea: Aristotelians treat mathematical facts as relations between properties. These properties, moreover, are abstracted from our experience of things. ...This view finds a natural companion in structuralism. | |
| From: Edwin D. Mares (A Priori [2011], 11.7) | |
| A reaction: This is the view of mathematics that I personally favour. The view that we abstract 'five' from a group of five pebbles is too simplistic, but this is the right general approach. |
| 6408 | Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling] |
| Full Idea: In order to deduce the theorems of mathematics from purely logical axioms, Russell had to add three new axioms to those of standards logic, which were: the axiom of infinity, the axiom of choice, and the axiom of reducibility. | |
| From: A.C. Grayling (Russell [1996], Ch.2) | |
| A reaction: The third one was adopted to avoid his 'barber' paradox, but many thinkers do not accept it. The interesting question is why anyone would 'accept' or 'reject' an axiom. |
| 18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
| Full Idea: For the intuitionist, talk of mathematical objects is rather misleading. For them, there really isn't anything that we should call the natural numbers, but instead there is counting. What intuitionists study are processes, such as counting and collecting. | |
| From: Edwin D. Mares (Negation [2014], 5.1) | |
| A reaction: That is the first time I have seen mathematical intuitionism described in a way that made it seem attractive. One might compare it to a metaphysics based on processes. Apparently intuitionists struggle with infinite sets and real numbers. |
| 17703 | Light in straight lines is contingent a priori; stipulated as straight, because they happen to be so [Mares] |
| Full Idea: It seems natural to claim that light rays moving in straight lines is contingent but a priori. Scientists stipulate that they are the standard by which we measure straightness, but their appropriateness for this task is a contingent feature of the world. | |
| From: Edwin D. Mares (A Priori [2011], 02.9) | |
| A reaction: This resembles the metre rule in Paris. It is contingent that something is a certain way, so we make being that way a conventional truth, which can therefore be known via the convention, rather than via the contingent fact. |
| 6414 | Two propositions might seem self-evident, but contradict one another [Grayling] |
| Full Idea: Two propositions might contradict each other despite appearing self-evident when considered separately. | |
| From: A.C. Grayling (Russell [1996], Ch.2) | |
| A reaction: Russell's proposal (Idea 5416) is important here, that self-evidence comes in degrees. If self-evidence was all-or-nothing, Grayling's point would be a major problem, but it isn't. Bonjour explores the idea more fully (e.g. Idea 3704) |
| 17714 | Aristotelians dislike the idea of a priori judgements from pure reason [Mares] |
| Full Idea: Aristotelians tend to eschew talk about a special faculty of pure reason that is responsible for all of our a priori judgements. | |
| From: Edwin D. Mares (A Priori [2011], 08.9) | |
| A reaction: He is invoking Carrie Jenkins's idea that the a priori is knowledge of relations between concepts which have been derived from experience. Nice idea. We thus have an empirical a priori, integrated into the natural world. Abstraction must be involved. |
| 17705 | Empiricists say rationalists mistake imaginative powers for modal insights [Mares] |
| Full Idea: Empiricist critiques of rationalism often accuse rationalists of confusing the limits of their imaginations with real insight into what is necessarily true. | |
| From: Edwin D. Mares (A Priori [2011], 03.01) | |
| A reaction: See ideas on 'Conceivable as possible' for more on this. You shouldn't just claim to 'see' that something is true, but be willing to offer some sort of reason, truthmaker or grounding. Without that, you may be right, but you are on weak ground. |
| 17700 | The most popular view is that coherent beliefs explain one another [Mares] |
| Full Idea: In what is perhaps the most popular version of coherentism, a system of beliefs is a set of beliefs that explain one another. | |
| From: Edwin D. Mares (A Priori [2011], 01.5) | |
| A reaction: These seems too simple. My first response would be that explanations are what result from coherence sets of beliefs. I may have beliefs that explain nothing, but at least have the virtue of being coherent. |
| 17704 | Operationalism defines concepts by our ways of measuring them [Mares] |
| Full Idea: The central claim of Percy Bridgman's theory of operational definitions (1920s), is that definitions of certain scientific concepts are given by the ways that we have to measure them. For example, a straight line is 'the path of a light ray'. | |
| From: Edwin D. Mares (A Priori [2011], 02.9) | |
| A reaction: It is often observed that this captures the spirit of Special Relativity. |
| 7091 | The argument from analogy is not a strong inference, since the other being might be an actor or a robot [Grayling] |
| Full Idea: The argument from analogy is a weak one, because it does not logically guarantee the inference I draw to the other's inner states, for he might be dissimulating or acting, or may even be a cleverly contrived robot which feels nothing. | |
| From: A.C. Grayling (Wittgenstein [1988], Ch.3) | |
| A reaction: This gives the impression that for an argument to be strong it must logically guarantee its inference. It strikes me that analogy is a good reason for believing in other minds, but that is because I am looking for the best explanation, not logical proof. |
| 17710 | Aristotelian justification uses concepts abstracted from experience [Mares] |
| Full Idea: Aristotelian justification is the process of reasoning using concepts that are abstracted from experience (rather than, say, concepts that are innate or those that we associate with the meanings of words). | |
| From: Edwin D. Mares (A Priori [2011], 08.1) | |
| A reaction: See Carrie Jenkins for a full theory along these lines (though she doesn't mention Aristotle). This is definitely my preferred view of concepts. |
| 17706 | The essence of a concept is either its definition or its conceptual relations? [Mares] |
| Full Idea: In the 'classical theory' a concept includes in it those concepts that define it. ...In the 'theory theory' view the content of a concept is determined by its relationship to other concepts. | |
| From: Edwin D. Mares (A Priori [2011], 03.10) | |
| A reaction: Neither of these seem to give an intrinsic account of a concept, or any account of how the whole business gets off the ground. |
| 18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
| Full Idea: In 'situation semantics' individuals, properties, facts, and events are treated as abstractions from situations. | |
| From: Edwin D. Mares (Negation [2014], 6.1) | |
| A reaction: [Barwise and Perry 1983 are cited] Since I take the process of abstraction to be basic to thought, I am delighted to learn that someone has developed a formal theory based on it. I am immediately sympathetic to situation semantics. |
| 17701 | Possible worlds semantics has a nice compositional account of modal statements [Mares] |
| Full Idea: Possible worlds semantics is appealing because it gives a compositional analysis of the truth conditions of statements about necessity and possibility. | |
| From: Edwin D. Mares (A Priori [2011], 02.2) | |
| A reaction: Not sure I get this. Is the meaning composed by the gradual addition of worlds? If not, how is meaning composed in the normal way, from component words and phrases? |
| 17702 | Unstructured propositions are sets of possible worlds; structured ones have components [Mares] |
| Full Idea: An unstructured proposition is a set of possible worlds. ....Structured propositions contain entities that correspond to various parts of the sentences or thoughts that express them. | |
| From: Edwin D. Mares (A Priori [2011], 02.3) | |
| A reaction: I am definitely in favour of structured propositions. It strikes me as so obvious as to be not worth discussion - so I am obviously missing something here. Mares says structured propositions are 'more convenient'. |
| 7293 | It is legitimate to do harm if it is the unintended side-effect of an effort to achieve a good [Grayling] |
| Full Idea: The doctrine of double effect says that it is legitimate to do harm if the harm is the unintended side-effect of an effort to achieve a legitimate goal. | |
| From: A.C. Grayling (Among the Dead Cities [2006], Ch.6) | |
| A reaction: I think a key principle of morality is our duty to think about possible unnoticed consequences of our actions. To neglect concern for side-effects is wicked. Beyond that, the issue must concern the particulars of the situation. |
| 7809 | In an honour code shame is the supreme punishment, and revenge is a duty [Grayling] |
| Full Idea: An honour code is one in which the greatest punishment is shame, and in which revenge is a duty. | |
| From: A.C. Grayling (What is Good? [2003], Ch.2) | |
| A reaction: Is this really what Nietzsche wanted to revive? Shame isn't a private matter - it needs solidarity of values in the community, and contempt for dishonour, so that it becomes everyone's worst fear. |
| 23262 | Experience, sympathy and history are sensible grounds for laying claim to rights [Grayling] |
| Full Idea: Personal experience, social sympathies, and history together licence laying claim to rights …which we see to make good mutual as well as individual sense. | |
| From: A.C. Grayling (The Good State [2020], 6) | |
| A reaction: There are no such thing as natural rights, but there are clearly natural grounds on which it is very reasonable to base a claim for legal rights. If positive rights are just arbitrary, or expressions of power struggles, that is crazy. |
| 23263 | Politics is driven by power cliques [Grayling] |
| Full Idea: What drives political history is power cliques. | |
| From: A.C. Grayling (The Good State [2020], Conc) | |
| A reaction: A simple ideas which strikes me as accurate. Alternative views are that power is universally distributed (Foucault), or that power resides in a social class (Marx). Grayling's idea strikes me as more accurate. Each class has its cliques. |
| 23255 | It is essential for democracy that voting is free and well informed [Grayling] |
| Full Idea: A necessary condition for democracy to be realised is that the act of voting should be free and informed. | |
| From: A.C. Grayling (The Good State [2020], p.25) | |
| A reaction: The requirement that voters should be well informed has become an increasing modern problem, because the media are owned by the wealthy, and false rumours can spread at lightning speed. |
| 23254 | Democracies should require a supermajority for major questions [Grayling] |
| Full Idea: A threshhold or supermajority bar (such as 60%) is the appropriate way to deal with highly consequential questions. | |
| From: A.C. Grayling (The Good State [2020], p.23) | |
| A reaction: This seems to be a very conservative view, because rejection of a major change is a decision in favour of the status quo. Would this rule apply equally to abolishing capital punishment and to reintroducing it? |
| 23260 | A cap on time of service would restrict party control and career ambitions [Grayling] |
| Full Idea: A method by which legislators can be rendered independent of both party control and career ambitions is a cap on the amount of time they can serve as legislators. | |
| From: A.C. Grayling (The Good State [2020], 4) | |
| A reaction: The time of service must allow for learning the job, and then using the wisdom of experience. Presumably some career ambitions are needed if we are to have leaders. Not all party discipline is bad; great achievements are hard without it. |
| 23253 | Majority decisions are only acceptable if the minority interests are not vital [Grayling] |
| Full Idea: A majority being in favour of some course of action is the acceptable means of reaching decisions when no vital interest of a minority is endangered. | |
| From: A.C. Grayling (The Good State [2020], 1) | |
| A reaction: This is generally accepted in extreme cases, such as the majority voting to exterminate the minority. The difficulty is to decide what is a 'vital' interest, and to get the majority to care about it. |
| 23256 | Liberty and equality cannot be reconciled [Grayling] |
| Full Idea: Liberty and equality appear to be irresolvable contradictions. | |
| From: A.C. Grayling (The Good State [2020], 2) | |
| A reaction: [He particularly cites Isaiah Berlin for this view] Hm. The liberty of one is the liberty of all. I don't think I would feel that my liberty was unreasonably infringed if I lived in a society of imposed equality. The greedy hate equality the most. |
| 23258 | The very concept of democracy entails a need for justice [Grayling] |
| Full Idea: The concept of democracy - embodying the principles of participation and equal concern - entails that social justice is a mandatory aim. | |
| From: A.C. Grayling (The Good State [2020], 2) | |
| A reaction: The idea that democracy entails participation in any direct way is what the right wing reject. Sustained participation would presumably entail various sorts of justice. |
| 23259 | There should be separate legislative, executive and judicial institutions [Grayling] |
| Full Idea: The obvious solution is where the legislative, executive and judicial powers are exercised by different institutions, distinguished by function. The executive is answerable to the legislative, and the judicial is controlled by neither. | |
| From: A.C. Grayling (The Good State [2020], 3) | |
| A reaction: Separation by institution, rather than merely by separate individuals exercising the powers. I agree (with Popper etc) that institutions are the way to secure long-term success and justice. Grayling says the judiciary must not paralyse government. |
| 7292 | War must also have a good chance of success, and be waged with moderation [Grayling] |
| Full Idea: To Aquinas's three conditions for war (Idea 7291) modern theorists have added two others: that to be just a war must have a reasonable chance of success, and that the means used to conduct it must be proportional to the ends sought. | |
| From: A.C. Grayling (Among the Dead Cities [2006], Ch.6) | |
| A reaction: These two principles strike me as being much more civilized and humane than Aquinas's original contribution, suggesting that in our theoretical thinking we might be making some progress. |
| 7907 | Human killing is worse if the victim is virtuous [Buddhaghosa] |
| Full Idea: In the case of humans killing is the more blameworthy the more virtuous the victim is. | |
| From: Buddhaghosa (Papancasudani [c.400], 9.7-10) | |
| A reaction: This sentiment has almost become a taboo in western society, and yet it is present all the time. The greatest outcry is about murders of really good citizens. Occasionally the murder of a villain causes little regret. |
| 7824 | If suicide is lawful, but assisting suicide is unlawful, powerless people are denied their rights [Grayling] |
| Full Idea: An anomaly created by England's 1961 Suicide Act is that it is lawful to take one's own life, but unlawful to help anyone else to do it. This means anyone unable to commit suicide without help is denied one of their fundamental rights. | |
| From: A.C. Grayling (What is Good? [2003], Ch.8) | |
| A reaction: There is a difference, not really captured either by law or by reason, between tolerating an activity, and encouraging and helping it. I think the test question is "this activity is legal, but would you want your child to do it?" |
| 17708 | Maybe space has points, but processes always need regions with a size [Mares] |
| Full Idea: One theory is that space is made up of dimensionless points, but physical processes cannot take place in regions of less than a certain size. | |
| From: Edwin D. Mares (A Priori [2011], 06.7) | |
| A reaction: Thinkers in sympathy with verificationism presumably won't like this, and may prefer Feynman's view. |
| 7819 | Religion gives answers, comforts, creates social order, and panders to superstition [Grayling] |
| Full Idea: The four standard explanations given for religion are that it provides answer, that it gives comfort, that it makes for social order, and that it rests on mere superstition. | |
| From: A.C. Grayling (What is Good? [2003], Ch.4) | |
| A reaction: All four of these could be correct, though the first and fourth would be incompatible if religion gives correct answers. Why religion begins might be not the same as the reason why it continues. |
| 7817 | To make an afterlife appealing, this life has to be denigrated [Grayling] |
| Full Idea: It is remarkable how much the life of this world has to be denigrated to make the promise of happiness after death appealing. | |
| From: A.C. Grayling (What is Good? [2003], Ch.4) | |
| A reaction: This seems to be true of most religions, but it could be otherwise. Surely you want such a wonderful life to continue after death? But then you would not be obliged to do anything difficult to achieve immortality. Power comes into it... |
| 7818 | In Greek mythology only heroes can go to heaven [Grayling] |
| Full Idea: In Greek mythology only a hero like Hercules could hope to go to heaven (by becoming a god himself). | |
| From: A.C. Grayling (What is Good? [2003], Ch.4) | |
| A reaction: This illustrates Nietsche's 'inversion of morality' most clearly, because Christianity says that the person most likely to go to heaven is the humblest person. |