29 ideas
| 19066 | Philosophy aims to understand the world, through ordinary experience and science [Dummett] |
| Full Idea: Philosophy is an attempt to understand the world, as it is revealed to us both in our ordinary experience and by the discoveries and theories of science. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.311) | |
| A reaction: I don't see a sharp division between 'ordinary' and 'scientific'. I really like this idea, first because it makes 'understanding' central, and second because it wants both revelations. In discussing matter and time, there is too much emphasis on science. |
| 19067 | A successful proof requires recognition of truth at every step [Dummett] |
| Full Idea: For a demonstration to be cogent it is necessary that the passage from step to step involve a recognition of truth at each line. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.313) | |
| A reaction: Dummett cited Quine (esp. 1970) as having an almost entirely syntactic view of logic. Rumfitt points out that logic can move validly from one falsehood to another. Even a 'proof' might detour into falsehood, but it would not be a 'canonical' proof! |
| 19060 | Truth-tables are dubious in some cases, and may be a bad way to explain connective meaning [Dummett] |
| Full Idea: It is arguable whether two-valued truth tables give correct meanings for certain sentential operators, and even whether they constitute legitimate explanations of any possible sentential operators. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: See 'Many-valued logic' for examples of non-binary truth tables. Presumably logicians should aspire to make their semantics precise, as well as their syntax. |
| 11066 | Deduction is justified by the semantics of its metalanguage [Dummett, by Hanna] |
| Full Idea: For Dummett the semantics of the metalanguage is the external and objective source of the justification of deduction. | |
| From: report of Michael Dummett (The Justification of Deduction [1973]) by Robert Hanna - Rationality and Logic 3.4 | |
| A reaction: This is offered as an answer to the Lewis Carroll problem that justifying deduction seems to need deduction, thus leading to a regress. [There is a reply to Dummett by Susan Haack] |
| 19058 | Syntactic consequence is positive, for validity; semantic version is negative, with counterexamples [Dummett] |
| Full Idea: A plausible account is that the syntactic notion of consequence is for positive results, that some form of argument is valid; the semantic notion is required for negative results, that some argument is invalid, because a counterexample can be found. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.292) | |
| A reaction: This rings true for the two strategies of demonstration, the first by following the rules in steps, the second by using your imagination (or a tableau) to think up problems. |
| 19063 | Beth trees show semantics for intuitionistic logic, in terms of how truth has been established [Dummett] |
| Full Idea: Beth trees give a semantics for intuitionistic logic, by representing sentence meaning in terms of conditions under which it is recognised to have been established as true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) |
| 19059 | In standard views you could replace 'true' and 'false' with mere 0 and 1 [Dummett] |
| Full Idea: Nothing is lost, on this view, if in the standard semantic treatment of classical sentential logic, we replace the standard truth-values 'true' and 'false' by the numbers 0 and 1. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: [A long context will explain 'on this view'] He is discussing the relationship of syntactic and semantic consequence, and goes on to criticise simple binary truth-table accounts of connectives. Semantics on a computer would just be 0 and 1. |
| 19062 | Classical two-valued semantics implies that meaning is grasped through truth-conditions [Dummett] |
| Full Idea: The standard two-valued semantics for classical logic involves a conception under which to grasp the meaning of a sentence is to apprehend the conditions under which it is, or is not, true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) | |
| A reaction: The idea is that you only have to grasp the truth tables for sentential logic, and that needs nothing more than knowing whether a sentence is true or false. I'm not sure where the 'conditions' creep in, though. |
| 19065 | Soundness and completeness proofs test the theory of meaning, rather than the logic theory [Dummett] |
| Full Idea: A proof of soundess or completeness is a test, not so much of the logical theory to which it applies, but of the theory of meaning which underlies the semantics. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.310) | |
| A reaction: These two types of proof concern how the syntax and the semantics match up, so this claim sounds plausible, though I tend to think of them as more like roadworthiness tests for logic, checking how well they function. |
| 19061 | An explanation is often a deduction, but that may well beg the question [Dummett] |
| Full Idea: An explanation is often a deductive argument, with the fact needing explaining as its conclusion. ...But the conclusion is usually given in advance, and we may only believe the premisses because they plausibly explain the conclusion. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.296) | |
| A reaction: [compressed (Dummett's wordy prose cries out for it!)] I suppose this works better in mathematics, which is central to Dummett's interests. In the real world the puzzle is not usually logically implied by its explanation. |
| 19064 | Holism is not a theory of meaning; it is the denial that a theory of meaning is possible [Dummett] |
| Full Idea: In the sense of giving a model for the content of a sentence, its representative power, holism is not a theory of meaning; it is the denial that a theory of meaning is possible. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.309) | |
| A reaction: This will obviously be because sentences just don't have meaning in isolation, so their meaning can't be given in terms of the sentences. |
| 3772 | The will, in the beginning, is entirely produced by desire [Mill] |
| Full Idea: The will, in the beginning, is entirely produced by desire. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.4) | |
| A reaction: This is the sort of simplistic psychology that modern philosophers tend to avoid. Personally I am more Kantian. I will and desire that the answer to 3+2=? is 5, simply because it is true. Mill must realise we can will ourselves to desire something. |
| 3769 | With early training, any absurdity or evil may be given the power of conscience [Mill] |
| Full Idea: There is hardly anything so absurd or so mischievous that it may not, by means of early sanctions and influence, be made to act on the human mind with all the influence of conscience. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.3) | |
| A reaction: Like this! Think of all the people who have had weird upbringings, and end up feeling guilty about absurd things. Conscience just summarise upbringing and social conventions. |
| 3767 | Motive shows the worth of the agent, but not of the action [Mill] |
| Full Idea: The motive has nothing to do with the morality of the action, though much with the worth of the agent. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.2) | |
| A reaction: I think it is an error to try to separate these too sharply. Morality can't be purely consequential, because it would make earthquakes immoral. Actions indicate the worth of agents. |
| 3771 | Virtues only have value because they achieve some further end [Mill] |
| Full Idea: Utilitarians believe that actions and dispositions are only virtuous because they promote another end than virtue. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.4) |
| 3768 | Orthodox morality is the only one which feels obligatory [Mill] |
| Full Idea: The customary morality, that which education and opinion have consecrated, is the only one which presents itself to the mind with the feeling of being in itself obligatory. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.3) |
| 3776 | Utilitarianism only works if everybody has a totally equal right to happiness [Mill] |
| Full Idea: The Greatest Happiness Principle is a mere form of empty words unless one person's happiness, supposed equal in degree, is counted for exactly as much as another's (Bentham's "everybody to count for one, nobody for more than one"). | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.5) |
| 7202 | The English believe in the task of annihilating evil for the victory of good [Nietzsche on Mill] |
| Full Idea: One continues to believe in good and evil: in such a way that one feels the victory of good and the annihilation of evil to be a task (- this is English; a typical case is that shallow-headed John Stuart Mill). | |
| From: comment on John Stuart Mill (Utilitarianism [1861]) by Friedrich Nietzsche - Writings from Late Notebooks 11[148]e | |
| A reaction: The poor old English try very hard to be clear, sensible, practical and realistic, and get branded as 'shallow' for their pains. Nietzsche was a deeper thinker than Mill, but I would prefer Mill to Heidegger any day. |
| 5935 | Mill's qualities of pleasure is an admission that there are other good states of mind than pleasure [Ross on Mill] |
| Full Idea: Mill's introduction of quality of pleasures into the hedonistic calculus is an unconscious departure from hedonism and a half-hearted admission that there are other qualities than pleasantness in virtue of which states of mind are good. | |
| From: comment on John Stuart Mill (Utilitarianism [1861], Ch.2) by W. David Ross - The Right and the Good §VI | |
| A reaction: Mill argues that experienced people prefer some pleasures to others, but ducks the question of why they might prefer them. It can only be because they have some further desirable quality on top of the equal amount of pleasure. |
| 3764 | Actions are right if they promote pleasure, wrong if they promote pain [Mill] |
| Full Idea: The Greatest Happiness Principle holds that actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness. By happiness is intended pleasure, and the absence of pain. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.2) |
| 3763 | Ultimate goods such as pleasure can never be proved to be good [Mill] |
| Full Idea: What can be proved good must be so by being shown to be a means to something admitted to be good without proof. Music is good because it produces pleasure, but what proof is it possible to give that pleasure is good? | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.1) |
| 3765 | Only pleasure and freedom from pain are desirable as ends [Mill] |
| Full Idea: Pleasure and freedom from pain are the only things desirable as ends. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.2) |
| 3766 | Better to be Socrates dissatisfied than a fool satisfied [Mill] |
| Full Idea: Better to be Socrates dissatisfied than a fool satisfied. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.2) |
| 3770 | General happiness is only desirable because individuals desire their own happiness [Mill] |
| Full Idea: No reason can be given why the general happiness is desirable, except that each person, so far as he believes it to be attainable, desires his own happiness. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.4) |
| 6697 | Moral rules protecting human welfare are more vital than local maxims [Mill] |
| Full Idea: Moral rules which forbid mankind to hurt one another are more vital to human well-being than any maxims about some department of human affairs; ..though in particular cases a social duty is so important, as to overrule any general maxim of justice. | |
| From: John Stuart Mill (Utilitarianism [1861]), quoted by Gordon Graham - Eight Theories of Ethics Ch.7 | |
| A reaction: The qualification is realistic, but raises the question of whether an 'act' calculation will always overrule any 'rule'. Maybe rule utilitirianism is just act utilitarianism, but ensuring that the calculations are long-term and extensive. (1871 edn) |
| 3774 | Rights are a matter of justice, not of benevolence [Mill] |
| Full Idea: Wherever there is a right, the case is one of justice, and not of the virtue of benevolence. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.5) |
| 3773 | No individual has the right to receive our benevolence [Mill] |
| Full Idea: No one has a moral right to our generosity or beneficence, because we are not morally bound to practise those virtues towards any given individual. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.5) |
| 3775 | A right is a valid claim to society's protection [Mill] |
| Full Idea: When we call anything a person's right, we mean that he has a valid claim on society to protect him in the possession of it. | |
| From: John Stuart Mill (Utilitarianism [1861], Ch.5) |
| 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. |