23 ideas
13407 | All worthwhile philosophy is synthetic theorizing, evaluated by experience [Papineau] |
Full Idea: I would say that all worthwhile philosophy consists of synthetic theorizing, evaluated against experience. | |
From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §1) | |
A reaction: This is the view that philosophy is just science at a high level of abstraction, and he explicitly rejects 'conceptual analysis' as a fruitful activity. I need to take a stance on this one, but find I am in a state of paralysis. Welcome to philosophy... |
8472 | Sentential logic is consistent (no contradictions) and complete (entirely provable) [Orenstein] |
Full Idea: Sentential logic has been proved consistent and complete; its consistency means that no contradictions can be derived, and its completeness assures us that every one of the logical truths can be proved. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
A reaction: The situation for quantificational logic is not quite so clear (Orenstein p.98). I do not presume that being consistent and complete makes it necessarily better as a tool in the real world. |
8476 | Axiomatization simply picks from among the true sentences a few to play a special role [Orenstein] |
Full Idea: In axiomatizing, we are merely sorting out among the truths of a science those which will play a special role, namely, serve as axioms from which we derive the others. The sentences are already true in a non-conventional or ordinary sense. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
A reaction: If you were starting from scratch, as Euclidean geometers may have felt they were doing, you might want to decide which are the simplest truths. Axiomatizing an established system is a more advanced activity. |
8480 | S4: 'poss that poss that p' implies 'poss that p'; S5: 'poss that nec that p' implies 'nec that p' [Orenstein] |
Full Idea: The five systems of propositional modal logic contain successively stronger conceptions of necessity. In S4 'it is poss that it is poss that p' implies 'it is poss that p'. In S5, 'it is poss that it is nec that p' implies 'it is nec that p'. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.7) | |
A reaction: C.I. Lewis originated this stuff. Any serious student of modality is probably going to have to pick a system. E.g. Nathan Salmon says that the correct modal logic is even weaker than S4. |
8474 | Unlike elementary logic, set theory is not complete [Orenstein] |
Full Idea: The incompleteness of set theory contrasts sharply with the completeness of elementary logic. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
A reaction: This seems to be Quine's reason for abandoning the Frege-Russell logicist programme (quite apart from the problems raised by Gödel. |
8465 | Mereology has been exploited by some nominalists to achieve the effects of set theory [Orenstein] |
Full Idea: The theory of mereology has had a history of being exploited by nominalists to achieve some of the effects of set theory. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.3) | |
A reaction: Some writers refer to mereology as a 'theory', and others as an area of study. This appears to be an interesting line of investigation. Orenstein says Quine and Goodman showed its limitations. |
8452 | Traditionally, universal sentences had existential import, but were later treated as conditional claims [Orenstein] |
Full Idea: In traditional logic from Aristotle to Kant, universal sentences have existential import, but Brentano and Boole construed them as universal conditionals (such as 'for anything, if it is a man, then it is mortal'). | |
From: Alex Orenstein (W.V. Quine [2002], Ch.2) | |
A reaction: I am sympathetic to the idea that even the 'existential' quantifier should be treated as conditional, or fictional. Modern Christians may well routinely quantify over angels, without actually being committed to them. |
8475 | The substitution view of quantification says a sentence is true when there is a substitution instance [Orenstein] |
Full Idea: The substitution view of quantification explains 'there-is-an-x-such-that x is a man' as true when it has a true substitution instance, as in the case of 'Socrates is a man', so the quantifier can be read as 'it is sometimes true that'. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
A reaction: The word 'true' crops up twice here. The alternative (existential-referential) view cites objects, so the substitution view is a more linguistic approach. |
8454 | The whole numbers are 'natural'; 'rational' numbers include fractions; the 'reals' include root-2 etc. [Orenstein] |
Full Idea: The 'natural' numbers are the whole numbers 1, 2, 3 and so on. The 'rational' numbers consist of the natural numbers plus the fractions. The 'real' numbers include the others, plus numbers such a pi and root-2, which cannot be expressed as fractions. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.2) | |
A reaction: The 'irrational' numbers involved entities such as root-minus-1. Philosophical discussions in ontology tend to focus on the existence of the real numbers. |
8473 | The logicists held that is-a-member-of is a logical constant, making set theory part of logic [Orenstein] |
Full Idea: The question to be posed is whether is-a-member-of should be considered a logical constant, that is, does logic include set theory. Frege, Russell and Whitehead held that it did. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
A reaction: This is obviously the key element in the logicist programme. The objection seems to be that while first-order logic is consistent and complete, set theory is not at all like that, and so is part of a different world. |
13409 | Our best theories may commit us to mathematical abstracta, but that doesn't justify the commitment [Papineau] |
Full Idea: Our empirically best-supported theories may commit us to certain abstract mathematical entities, but this does not necessarily mean that this is what justifies our commitment. That we are committed doesn't explain why we should be. | |
From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §4) | |
A reaction: A nice point. It is only a slightly gormless scientism which would say that we have to accept whatever scientists demand. Who's in charge here - scientists, mathematicians or philosophers? Don't answer that... |
8458 | Just individuals in Nominalism; add sets for Extensionalism; add properties, concepts etc for Intensionalism [Orenstein] |
Full Idea: Modest ontologies are Nominalism (Goodman), admitting only concrete individuals; and Extensionalism (Quine/Davidson) which admits individuals and sets; but Intensionalists (Frege/Carnap/Church/Marcus/Kripke) may have propositions, properties, concepts. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.3) | |
A reaction: I don't like sets, because of Idea 7035. Even the ontology of individuals could collapse dramatically (see the ideas of Merricks, e.g. 6124). The intensional items may be real enough, but needn't have a place at the ontological high table. |
13406 | A priori knowledge is analytic - the structure of our concepts - and hence unimportant [Papineau] |
Full Idea: I am a fully paid up-naturalist, but I see no reason to deny that a priori knowledge is possible. My view is that a priori knowledge is unimportant (esp to philosophy). If there is a priori knowledge, it is analytic, true by the structure of our concepts. | |
From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §1) | |
A reaction: It is one thing to say it is the structure of our concepts, and another to infer that it is unimportant. I take the structure of our concepts to be a shadow cast by the structure of the world. E.g. the structure of numbers reveals the world. |
13408 | Intuition and thought-experiments embody substantial information about the world [Papineau] |
Full Idea: Naturalists can allow for thought-experiments in philosophy. Intuitions play an important role, but only because they embody substantial information about the world. | |
From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §3) | |
A reaction: In this sense, intuitions are just memories which are too complex for us to articulate. They are not the intuitions of 'pure reason'. It is hard to connect the intuitive spotting of a proof with memories of the physical world. |
8457 | The Principle of Conservatism says we should violate the minimum number of background beliefs [Orenstein] |
Full Idea: The principle of conservatism in choosing between theories is a maxim of minimal mutilation, stating that of competing theories, all other things being equal, choose the one that violates the fewest background beliefs held. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.2) | |
A reaction: In this sense, all rational people should be conservatives. The idea is a modern variant of Hume's objection to miracles (Idea 2227). A Kuhnian 'paradigm shift' is the dramatic moment when this principle no longer seems appropriate. |
13410 | Verificationism about concepts means you can't deny a theory, because you can't have the concept [Papineau] |
Full Idea: Verificationism about concepts implies that thinkers will not share concepts with adherents of theories they reject. Those who reject the phlogiston theory will not possess the same concept as adherents, so cannot say 'there is no phlogiston'. | |
From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §6) | |
A reaction: The point seems to be more general - that it is hard to see how you can have a concept of anything which doesn't actually exist, if the concept is meant to rest on some sort of empirical verification. |
8477 | People presume meanings exist because they confuse meaning and reference [Orenstein] |
Full Idea: A good part of the confidence people have that there are meanings rests on the confusion of meaning and reference. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.6) | |
A reaction: An important point. Everyone assumes that sentences link to the world, but Frege shows that that is not part of meaning. Words like prepositions and conjunctions ('to', 'and') don't have 'a meaning' apart from their function and use. |
8471 | Three ways for 'Socrates is human' to be true are nominalist, platonist, or Montague's way [Orenstein] |
Full Idea: 'Socrates is human' is true if 1) subject referent is identical with a predicate referent (Nominalism), 2) subject reference member of the predicate set, or the subject has that property (Platonism), 3) predicate set a member of the subject set (Montague) | |
From: Alex Orenstein (W.V. Quine [2002], Ch.3) | |
A reaction: Orenstein offers these as alternatives to Quine's 'inscrutability of reference' thesis, which makes the sense unanalysable. |
8484 | If two people believe the same proposition, this implies the existence of propositions [Orenstein] |
Full Idea: If we can say 'there exists a p such that John believes p and Barbara believes p', logical forms such as this are cited as evidence for our ontological commitment to propositions. | |
From: Alex Orenstein (W.V. Quine [2002], Ch.7) | |
A reaction: Opponents of propositions (such as Quine) will, of course, attempt to revise the logical form to eliminate the quantification over propositions. See Orenstein's outline on p.171. |
20883 | Modern utilitarians value knowledge, friendship, autonomy, and achievement, as well as pleasure [Hooker,B] |
Full Idea: Most utilitarians now think that pleasure, even if construed widely, is not the only thing desirable in itself. ...Goods also include important knowledge, friendship, autonomy, achievement and so on. | |
From: Brad W. Hooker (Rule Utilitarianism and Euthanasia [1997], 2) | |
A reaction: That pleasure is desired is empirically verifiable, which certainly motivated Bentham. A string of other desirables each needs to be justified - but how? What would be the value of a 'friendship' if neither party got pleasure from it? |
20884 | Rule-utilitarians prevent things like torture, even on rare occasions when it seems best [Hooker,B] |
Full Idea: For rule-utilitarians acts of murder, torture and so on, can be impermissible even in rare cases where they really would produce better consequences than any alternative act. | |
From: Brad W. Hooker (Rule Utilitarianism and Euthanasia [1997], 4) | |
A reaction: It is basic to rule-utilitarianism that it trumps act-ulitilarianism, even when a particular act wins the utilitarian calculation. But that is hard to understand. Only long-term benefit could justify the rule - but that should win the calculation. |
20885 | Euthanasia is active or passive, and voluntary, non-voluntary or involuntary [Hooker,B] |
Full Idea: Six types of euthanasia: 1) Active voluntary (knowing my wishes), 2) Active non-voluntary (not knowing my wishes), 3) Active involuntary (against my wishes), 4) Passive voluntary, 5) Passive non-voluntary, 6) Passive involuntary. | |
From: Brad W. Hooker (Rule Utilitarianism and Euthanasia [1997], 5) | |
A reaction: 'Active' is intervening, and 'passive' is not intervening. A helpful framework. |
20882 | Euthanasia may not involve killing, so it is 'killing or not saving, out of concern for that person' [Hooker,B] |
Full Idea: Passive euthanasia is arguably not killing, and the death involved is often painful, so let us take the term 'euthanasia' to mean 'either killing or passing up opportunities to save someone, out of concern for that person'. | |
From: Brad W. Hooker (Rule Utilitarianism and Euthanasia [1997], 1) | |
A reaction: This sounds good, and easily settled, until you think concern for that person could have two different outcomes, depending on whether the criteria are those of the decider or of the patient. Think of religious decider and atheist patient, or vice versa. |