30 ideas
18859 | Metaphysics is a quest for truthmakers [Tallant] |
Full Idea: In this book I will treat metaphysics as a quest for truthmakers. | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 01) | |
A reaction: I find this appealing, though obviously you have to say what sort of truthmakers generate 'metaphysical' truths, as opposed to physics or biology. I take it that would involve truthmakers that had a high level of generality, idealisation and abstraction. |
18861 | Maybe number statements can be paraphrased into quantifications plus identities [Tallant] |
Full Idea: One strategy is whenever we are presented with a sentence that might appear to entail the existence of numbers, all that we have to do is paraphrase it using a quantified logic, plus identity. | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 03.5) | |
A reaction: This nominalist strategy seems fine for manageable numbers, but gets in trouble with numbers too big to count (e.g. grains of sand in the world) , or genuine infinities. |
3745 | Must sentences make statements to qualify for truth? [O'Connor] |
Full Idea: Maybe a sentence is not a candidate for truth until it is used to make a statement. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.6) |
18866 | Maybe only 'positive' truths need truth-makers [Tallant] |
Full Idea: We might say that those truths that do not need truth-makers are those that are negative. Those that do need truth-makers are those that are positive. | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 10.8) | |
A reaction: If you deny the existence of something, there is always an implicit domain for the denial, such as 'on the table', or 'in this building', or 'in the cosmos'. So why can't that domain be the truthmaker for a negative existential? |
18860 | A truthmaker is the minimal portion of reality that will do the job [Tallant] |
Full Idea: A 'minimal' truth-maker is the 'smallest' portion of reality required to make a given proposition true. | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 01.2) | |
A reaction: A nice suggestion. This seems to make Ockham's Razor an integral part of the theory of truth-makers. I would apply the same principle to explanations. An Ockhamist explanation is what explains the puzzling thing - and nothing else. |
18863 | What is the truthmaker for a possible new power? [Tallant] |
Full Idea: What power will make true 'there could be a power that does not in fact exist'? | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 04.13) | |
A reaction: Nice question. We can't know whether it is true that a new power could exist, so we can't expect an actual truthmaker for it. Though we might predict new powers (such as for a new transuranic element), on the basis of the known ones. |
3742 | Beliefs must match facts, but also words must match beliefs [O'Connor] |
Full Idea: Our beliefs must claim a correspondence with facts, and then the verbal expression of the belief must correspond to the belief itself. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.4) |
3744 | The semantic theory requires sentences as truth-bearers, not propositions [O'Connor] |
Full Idea: The Semantic Theory of truth requires that sentences are truth-bearers (rather than statements, or propositions). | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.6) |
3749 | What does 'true in English' mean? [O'Connor] |
Full Idea: We do not seem to have any use in ordinary discourse for phrases like 'true in English', 'false in German'. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], II.1) |
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. |
3746 | Logic seems to work for unasserted sentences [O'Connor] |
Full Idea: If sentences can have truth-values only when they occur as asserted, it would be impossible to have a truth-functional basis to logic. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.6) |
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. |
3747 | Events are fast changes which are of interest to us [O'Connor] |
Full Idea: The standard cases of events are physical changes which happen sufficiently fast to be observed as changes, and which are of sufficient interest to us to be noticed or commented on. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.7) |
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. |
18864 | The wisdom of Plato and of Socrates are not the same property [Tallant] |
Full Idea: It is not the case that Plato's wisdom = Socrates's wisdom. Platonic-wisdom and Socratic-wisdom are not the same property. | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 05.4) | |
A reaction: This seems reasonable in the case of wisdom, but not so clear in the case of indistinguishable properties of redness or squareness or mass. Nevertheless it gives nice support for trope theory. |
18865 | Substance must have two properties: individuation, and property-bearing [Tallant] |
Full Idea: It appears that substance has essential properties: it is of the essence of substance that it individuates, and it is of the essence of substance that it bears properties. | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 06.2) | |
A reaction: The point being that substances are not 'bear', because they have a role to perform, and a complete blank can't fulfil a role. We can't take substance, though, seriously in ontology. It is just a label for distinct individuals. |
3743 | We can't contemplate our beliefs until we have expressed them [O'Connor] |
Full Idea: It is only when beliefs are given some symbolic expression that they acquire the precision and stability that enables us to entertain them. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.5) |
3748 | Without language our beliefs are particular and present [O'Connor] |
Full Idea: Without language we would be restricted to particular beliefs about the here and now. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.8) |
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. |
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. |
18862 | Are propositions all the thoughts and sentences that are possible? [Tallant] |
Full Idea: One might be tempted to the view that there are as many different propositions as there are thoughts that could be thought and sentences that could be uttered. | |
From: Jonathan Tallant (Metaphysics: an introduction [2011], 04.5.3) | |
A reaction: A fairly orthodox view I take to be crazy. I think it is a view designed for logic, rather than for how the world is. Why tie propositions to what can be thought, and then introduce unthought propositions? Why no unthinkable propositions? |
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. |