84 ideas
| 16241 | The metaphysics of nature should focus on physics [Maudlin] |
| Full Idea: Metaphysics, insofar as it is concerned with the natural world, can do no better than to reflect on physics. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], Intro) | |
| A reaction: I suppose so. Physics only works at one level of description. Metaphysics often works with concepts which only emerge at a more general level than physics. There are also many metaphysical problems which are of no interest to most physicists. |
| 16257 | Kant survives in seeing metaphysics as analysing our conceptual system, which is a priori [Maudlin] |
| Full Idea: The Kantian strain survives in the notion that metaphysics is not about the world, but about our 'conceptual system', especially as what structures our thought about the world. This keeps it a priori, and so not about the world itself. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 3) | |
| A reaction: Strawson would embody this view, I suppose. I take our conceptual system to be largely a reflection of (and even creation of) the world, and not just an arbitrary conventional attempt to grasp the world. Analysing concepts partly analyses the world. |
| 16276 | Wide metaphysical possibility may reduce metaphysics to analysis of fantasies [Maudlin] |
| Full Idea: If metaphysical possibility extends more widely than physical possibility, this may make metaphysics out to be nothing but the analysis of fantastical descriptions produced by philosophers. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 7 Epilogue) | |
| A reaction: Maudlin wants metaphysics to be firmly constrained in its possibilities by what scientific undestanding permits, and he is right. Metaphysics must integrate into science, or wither away on the margins. |
| 16244 | If the universe is profligate, the Razor leads us astray [Maudlin] |
| Full Idea: If the universe has been profligate, then Ockham's Razor will lead us astray. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], Intro) | |
| A reaction: That is, there may be a vast number of entities which exist beyond what seems to be 'necessary'. |
| 16255 | The Razor rightly prefers one cause of multiple events to coincidences of causes [Maudlin] |
| Full Idea: The Razor is good when it councils higher credence to explanations which posit a single cause to multiple events that occur in a striking pattern, over explanations involving coincidental multiple causes. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 2.5) | |
| A reaction: This is in the context of Maudlin warning against embracing the Razor too strongly. Presumably inductive success suggests that the world supports this particular use of the Razor. |
| 9535 | 'Contradictory' propositions always differ in truth-value [Lemmon] |
| Full Idea: Two propositions are 'contradictory' if they are never both true and never both false either, which means that ¬(A↔B) is a tautology. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9511 | We write the conditional 'if P (antecedent) then Q (consequent)' as P→Q [Lemmon] |
| Full Idea: We write 'if P then Q' as P→Q. This is called a 'conditional', with P as its 'antecedent', and Q as its 'consequent'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.2) | |
| A reaction: P→Q can also be written as ¬P∨Q. |
| 9510 | That proposition that either P or Q is their 'disjunction', written P∨Q [Lemmon] |
| Full Idea: If P and Q are any two propositions, the proposition that either P or Q is called the 'disjunction' of P and Q, and is written P∨Q. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.3) | |
| A reaction: This is inclusive-or (meaning 'P, or Q, or both'), and not exlusive-or (Boolean XOR), which means 'P, or Q, but not both'. The ∨ sign is sometimes called 'vel' (Latin). |
| 9509 | That proposition that both P and Q is their 'conjunction', written P∧Q [Lemmon] |
| Full Idea: If P and Q are any two propositions, the proposition that both P and Q is called the 'conjunction' of P and Q, and is written P∧Q. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.3) | |
| A reaction: [I use the more fashionable inverted-v '∧', rather than Lemmon's '&', which no longer seems to be used] P∧Q can also be defined as ¬(¬P∨¬Q) |
| 9512 | We write the 'negation' of P (not-P) as ¬ [Lemmon] |
| Full Idea: We write 'not-P' as ¬P. This is called the 'negation' of P. The 'double negation' of P (not not-P) would be written as ¬¬P. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.2) | |
| A reaction: Lemmons use of -P is no longer in use for 'not'. A tilde sign (squiggle) is also used for 'not', but some interpreters give that a subtly different meaning (involving vagueness). The sign ¬ is sometimes called 'hook' or 'corner'. |
| 9513 | We write 'P if and only if Q' as P↔Q; it is also P iff Q, or (P→Q)∧(Q→P) [Lemmon] |
| Full Idea: We write 'P if and only if Q' as P↔Q. It is called the 'biconditional', often abbreviate in writing as 'iff'. It also says that P is both sufficient and necessary for Q, and may be written out in full as (P→Q)∧(Q→P). | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.4) | |
| A reaction: If this symbol is found in a sequence, the first move in a proof is to expand it to the full version. |
| 9514 | If A and B are 'interderivable' from one another we may write A -||- B [Lemmon] |
| Full Idea: If we say that A and B are 'interderivable' from one another (that is, A |- B and B |- A), then we may write A -||- B. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9508 | The sign |- may be read as 'therefore' [Lemmon] |
| Full Idea: I introduce the sign |- to mean 'we may validly conclude'. To call it the 'assertion sign' is misleading. It may conveniently be read as 'therefore'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.2) | |
| A reaction: [Actually no gap between the vertical and horizontal strokes of the sign] As well as meaning 'assertion', it may also mean 'it is a theorem that' (with no proof shown). |
| 9516 | A 'well-formed formula' follows the rules for variables, ¬, →, ∧, ∨, and ↔ [Lemmon] |
| Full Idea: A 'well-formed formula' of the propositional calculus is a sequence of symbols which follows the rules for variables, ¬, →, ∧, ∨, and ↔. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.1) |
| 9517 | The 'scope' of a connective is the connective, the linked formulae, and the brackets [Lemmon] |
| Full Idea: The 'scope' of a connective in a certain formula is the formulae linked by the connective, together with the connective itself and the (theoretically) encircling brackets | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.1) |
| 9519 | A 'substitution-instance' is a wff formed by consistent replacing variables with wffs [Lemmon] |
| Full Idea: A 'substitution-instance' is a wff which results by replacing one or more variables throughout with the same wffs (the same wff replacing each variable). | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9529 | A wff is 'inconsistent' if all assignments to variables result in the value F [Lemmon] |
| Full Idea: If a well-formed formula of propositional calculus takes the value F for all possible assignments of truth-values to its variables, it is said to be 'inconsistent'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9531 | 'Contrary' propositions are never both true, so that ¬(A∧B) is a tautology [Lemmon] |
| Full Idea: If A and B are expressible in propositional calculus notation, they are 'contrary' if they are never both true, which may be tested by the truth-table for ¬(A∧B), which is a tautology if they are contrary. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9534 | Two propositions are 'equivalent' if they mirror one another's truth-value [Lemmon] |
| Full Idea: Two propositions are 'equivalent' if whenever A is true B is true, and whenever B is true A is true, in which case A↔B is a tautology. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9530 | A wff is 'contingent' if produces at least one T and at least one F [Lemmon] |
| Full Idea: If a well-formed formula of propositional calculus takes at least one T and at least one F for all the assignments of truth-values to its variables, it is said to be 'contingent'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9532 | 'Subcontrary' propositions are never both false, so that A∨B is a tautology [Lemmon] |
| Full Idea: If A and B are expressible in propositional calculus notation, they are 'subcontrary' if they are never both false, which may be tested by the truth-table for A∨B, which is a tautology if they are subcontrary. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9533 | A 'implies' B if B is true whenever A is true (so that A→B is tautologous) [Lemmon] |
| Full Idea: One proposition A 'implies' a proposition B if whenever A is true B is true (but not necessarily conversely), which is only the case if A→B is tautologous. Hence B 'is implied' by A. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9528 | A wff is a 'tautology' if all assignments to variables result in the value T [Lemmon] |
| Full Idea: If a well-formed formula of propositional calculus takes the value T for all possible assignments of truth-values to its variables, it is said to be a 'tautology'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9518 | A 'theorem' is the conclusion of a provable sequent with zero assumptions [Lemmon] |
| Full Idea: A 'theorem' of logic is the conclusion of a provable sequent in which the number of assumptions is zero. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: This is what Quine and others call a 'logical truth'. |
| 9398 | ∧I: Given A and B, we may derive A∧B [Lemmon] |
| Full Idea: And-Introduction (&I): Given A and B, we may derive A∧B as conclusion. This depends on their previous assumptions. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9397 | CP: Given a proof of B from A as assumption, we may derive A→B [Lemmon] |
| Full Idea: Conditional Proof (CP): Given a proof of B from A as assumption, we may derive A→B as conclusion, on the remaining assumptions (if any). | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9394 | MPP: Given A and A→B, we may derive B [Lemmon] |
| Full Idea: Modus Ponendo Ponens (MPP): Given A and A→B, we may derive B as a conclusion. B will rest on any assumptions that have been made. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9401 | ∨E: Derive C from A∨B, if C can be derived both from A and from B [Lemmon] |
| Full Idea: Or-Elimination (∨E): Given A∨B, we may derive C if it is proved from A as assumption and from B as assumption. This will also depend on prior assumptions. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9396 | DN: Given A, we may derive ¬¬A [Lemmon] |
| Full Idea: Double Negation (DN): Given A, we may derive ¬¬A as a conclusion, and vice versa. The conclusion depends on the assumptions of the premiss. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9393 | A: we may assume any proposition at any stage [Lemmon] |
| Full Idea: Assumptions (A): any proposition may be introduced at any stage of a proof. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9399 | ∧E: Given A∧B, we may derive either A or B separately [Lemmon] |
| Full Idea: And-Elimination (∧E): Given A∧B, we may derive either A or B separately. The conclusions will depend on the assumptions of the premiss. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9402 | RAA: If assuming A will prove B∧¬B, then derive ¬A [Lemmon] |
| Full Idea: Reduction ad Absurdum (RAA): Given a proof of B∧¬B from A as assumption, we may derive ¬A as conclusion, depending on the remaining assumptions (if any). | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9395 | MTT: Given ¬B and A→B, we derive ¬A [Lemmon] |
| Full Idea: Modus Tollendo Tollens (MTT): Given ¬B and A→B, we derive ¬A as a conclusion. ¬A depends on any assumptions that have been made | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9400 | ∨I: Given either A or B separately, we may derive A∨B [Lemmon] |
| Full Idea: Or-Introduction (∨I): Given either A or B separately, we may derive A∨B as conclusion. This depends on the assumption of the premisses. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9521 | 'Modus tollendo ponens' (MTP) says ¬P, P ∨ Q |- Q [Lemmon] |
| Full Idea: 'Modus tollendo ponens' (MTP) says that if a disjunction holds and also the negation of one of its disjuncts, then the other disjunct holds. Thus ¬P, P ∨ Q |- Q may be introduced as a theorem. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: Unlike Modus Ponens and Modus Tollens, this is a derived rule. |
| 9522 | 'Modus ponendo tollens' (MPT) says P, ¬(P ∧ Q) |- ¬Q [Lemmon] |
| Full Idea: 'Modus ponendo tollens' (MPT) says that if the negation of a conjunction holds and also one of its conjuncts, then the negation of the other conjunct holds. Thus P, ¬(P ∧ Q) |- ¬Q may be introduced as a theorem. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: Unlike Modus Ponens and Modus Tollens, this is a derived rule. |
| 9525 | We can change conditionals into negated conjunctions with P→Q -||- ¬(P ∧ ¬Q) [Lemmon] |
| Full Idea: The proof that P→Q -||- ¬(P ∧ ¬Q) is useful for enabling us to change conditionals into negated conjunctions | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9524 | We can change conditionals into disjunctions with P→Q -||- ¬P ∨ Q [Lemmon] |
| Full Idea: The proof that P→Q -||- ¬P ∨ Q is useful for enabling us to change conditionals into disjunctions. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9523 | De Morgan's Laws make negated conjunctions/disjunctions into non-negated disjunctions/conjunctions [Lemmon] |
| Full Idea: The forms of De Morgan's Laws [P∨Q -||- ¬(¬P ∧ ¬Q); ¬(P∨Q) -||- ¬P ∧ ¬Q; ¬(P∧Q) -||- ¬P ∨ ¬Q); P∧Q -||- ¬(¬P∨¬Q)] transform negated conjunctions and disjunctions into non-negated disjunctions and conjunctions respectively. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9527 | The Distributive Laws can rearrange a pair of conjunctions or disjunctions [Lemmon] |
| Full Idea: The Distributive Laws say that P ∧ (Q∨R) -||- (P∧Q) ∨ (P∧R), and that P ∨ (Q∨R) -||- (P∨Q) ∧ (P∨R) | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9526 | We can change conjunctions into negated conditionals with P→Q -||- ¬(P → ¬Q) [Lemmon] |
| Full Idea: The proof that P∧Q -||- ¬(P → ¬Q) is useful for enabling us to change conjunctions into negated conditionals. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9537 | Truth-tables are good for showing invalidity [Lemmon] |
| Full Idea: The truth-table approach enables us to show the invalidity of argument-patterns, as well as their validity. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.4) |
| 9538 | A truth-table test is entirely mechanical, but this won't work for more complex logic [Lemmon] |
| Full Idea: A truth-table test is entirely mechanical, ..and in propositional logic we can even generate proofs mechanically for tautological sequences, ..but this mechanical approach breaks down with predicate calculus, and proof-discovery is an imaginative process. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.5) |
| 9536 | If any of the nine rules of propositional logic are applied to tautologies, the result is a tautology [Lemmon] |
| Full Idea: If any application of the nine derivation rules of propositional logic is made on tautologous sequents, we have demonstrated that the result is always a tautologous sequent. Thus the system is consistent. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.4) | |
| A reaction: The term 'sound' tends to be used now, rather than 'consistent'. See Lemmon for the proofs of each of the nine rules. |
| 9539 | Propositional logic is complete, since all of its tautologous sequents are derivable [Lemmon] |
| Full Idea: A logical system is complete is all expressions of a specified kind are derivable in it. If we specify tautologous sequent-expressions, then propositional logic is complete, because we can show that all tautologous sequents are derivable. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.5) | |
| A reaction: [See Lemmon 2.5 for details of the proofs] |
| 13909 | Write '(∀x)(...)' to mean 'take any x: then...', and '(∃x)(...)' to mean 'there is an x such that....' [Lemmon] |
| Full Idea: Just as '(∀x)(...)' is to mean 'take any x: then....', so we write '(∃x)(...)' to mean 'there is an x such that....' | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) | |
| A reaction: [Actually Lemmon gives the universal quantifier symbol as '(x)', but the inverted A ('∀') seems to have replaced it these days] |
| 13902 | 'Gm' says m has property G, and 'Pmn' says m has relation P to n [Lemmon] |
| Full Idea: A predicate letter followed by one name expresses a property ('Gm'), and a predicate-letter followed by two names expresses a relation ('Pmn'). We could write 'Pmno' for a complex relation like betweenness. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) |
| 13911 | The 'symbols' are bracket, connective, term, variable, predicate letter, reverse-E [Lemmon] |
| Full Idea: I define a 'symbol' (of the predicate calculus) as either a bracket or a logical connective or a term or an individual variable or a predicate-letter or reverse-E (∃). | |
| From: E.J. Lemmon (Beginning Logic [1965], 4.1) |
| 13910 | Our notation uses 'predicate-letters' (for 'properties'), 'variables', 'proper names', 'connectives' and 'quantifiers' [Lemmon] |
| Full Idea: Quantifier-notation might be thus: first, render into sentences about 'properties', and use 'predicate-letters' for them; second, introduce 'variables'; third, introduce propositional logic 'connectives' and 'quantifiers'. Plus letters for 'proper names'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) |
| 13904 | Universal Elimination (UE) lets us infer that an object has F, from all things having F [Lemmon] |
| Full Idea: Our rule of universal quantifier elimination (UE) lets us infer that any particular object has F from the premiss that all things have F. It is a natural extension of &E (and-elimination), as universal propositions generally affirm a complex conjunction. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) |
| 13906 | With finite named objects, we can generalise with &-Intro, but otherwise we need ∀-Intro [Lemmon] |
| Full Idea: If there are just three objects and each has F, then by an extension of &I we are sure everything has F. This is of no avail, however, if our universe is infinitely large or if not all objects have names. We need a new device, Universal Introduction, UI. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) |
| 13908 | UE all-to-one; UI one-to-all; EI arbitrary-to-one; EE proof-to-one [Lemmon] |
| Full Idea: Univ Elim UE - if everything is F, then something is F; Univ Intro UI - if an arbitrary thing is F, everything is F; Exist Intro EI - if an arbitrary thing is F, something is F; Exist Elim EE - if a proof needed an object, there is one. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.3) | |
| A reaction: [My summary of Lemmon's four main rules for predicate calculus] This is the natural deduction approach, of trying to present the logic entirely in terms of introduction and elimination rules. See Bostock on that. |
| 13901 | Predicate logic uses propositional connectives and variables, plus new introduction and elimination rules [Lemmon] |
| Full Idea: In predicate calculus we take over the propositional connectives and propositional variables - but we need additional rules for handling quantifiers: four rules, an introduction and elimination rule for the universal and existential quantifiers. | |
| From: E.J. Lemmon (Beginning Logic [1965]) | |
| A reaction: This is Lemmon's natural deduction approach (invented by Gentzen), which is largely built on introduction and elimination rules. |
| 13903 | Universal elimination if you start with the universal, introduction if you want to end with it [Lemmon] |
| Full Idea: The elimination rule for the universal quantifier concerns the use of a universal proposition as a premiss to establish some conclusion, whilst the introduction rule concerns what is required by way of a premiss for a universal proposition as conclusion. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) | |
| A reaction: So if you start with the universal, you need to eliminate it, and if you start without it you need to introduce it. |
| 13905 | If there is a finite domain and all objects have names, complex conjunctions can replace universal quantifiers [Lemmon] |
| Full Idea: If all objects in a given universe had names which we knew and there were only finitely many of them, then we could always replace a universal proposition about that universe by a complex conjunction. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) |
| 13900 | 'Some Frenchmen are generous' is rendered by (∃x)(Fx→Gx), and not with the conditional → [Lemmon] |
| Full Idea: It is a common mistake to render 'some Frenchmen are generous' by (∃x)(Fx→Gx) rather than the correct (∃x)(Fx&Gx). 'All Frenchmen are generous' is properly rendered by a conditional, and true if there are no Frenchmen. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) | |
| A reaction: The existential quantifier implies the existence of an x, but the universal quantifier does not. |
| 9520 | The paradoxes of material implication are P |- Q → P, and ¬P |- P → Q [Lemmon] |
| Full Idea: The paradoxes of material implication are P |- Q → P, and ¬P |- P → Q. That is, since Napoleon was French, then if the moon is blue then Napoleon was French; and since Napoleon was not Chinese, then if Napoleon was Chinese, the moon is blue. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: This is why the symbol → does not really mean the 'if...then' of ordinary English. Russell named it 'material implication' to show that it was a distinctively logical operator. |
| 21963 | It is possible that an omnipotent God might make one and two fail to equal three [Descartes] |
| Full Idea: Since every basic truth depends on God's omnipotence, I would not dare to say that God cannot make it....that one and two should not be three. | |
| From: René Descartes (Letters to Antoine Arnauld [1645]), quoted by A.W. Moore - The Evolution of Modern Metaphysics 01.3 | |
| A reaction: An unusual view. Most people would say that if Descartes can doubt something that simple, he should also doubt his reasons for believing in God's existence. |
| 16243 | The Humean view is wrong; laws and direction of time are primitive, and atoms are decided by physics [Maudlin] |
| Full Idea: The Humean project is unjustified, in that both the laws of nature and the direction of time require no analysis, and is misconceived, in that the atoms it employs do not correspond to present physical ontology. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], Intro) | |
| A reaction: I certainly find it strange, or excessively empirical, that Lewis thinks our account of reality should rest on 'qualities'. Maudlin's whole books is an implicit attack on David Lewis. |
| 16271 | Lewis says it supervenes on the Mosaic, but actually thinks the Mosaic is all there is [Maudlin] |
| Full Idea: At base it is not merely, as Lewis says, that everything else supervenes on the Mosaic; but rather that anything that exists at all is just a feature or element or generic property of the Mosaic. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 6) | |
| A reaction: [Maudlin has just quoted Idea 16210] Correct about Lewis, but Lewis just has a normal view of supervenience. Only 'emergentists' would think the supervenience allowed anything more, and they are deeply misguided, and in need of help. |
| 16273 | If the Humean Mosaic is ontological bedrock, there can be no explanation of its structure [Maudlin] |
| Full Idea: The Humean Mosaic appears to admit of no further explanation. Since it is the ontological bedrock, …none of the further things can account for the structure of the Mosaic itself. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 6) | |
| A reaction: A very nice point, reminiscent of Popper's objection to essentialism, that he thought it blocked further enquiry, when actually further enquiry was possible. Lewis and Hume seem too mesmerised by epistemology. They need best explanation. |
| 16275 | The 'spinning disc' is just impossible, because there cannot be 'homogeneous matter' [Maudlin] |
| Full Idea: The 'spinning disc' is not metaphysically possible. We have every reason to believe that there is no such thing as 'perfectly homogeneous matter'. The atomic theory of matter is as well established as any scientific theory is likely to be. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 7 Epilogue) | |
| A reaction: This is a key case for Maudlin, and his contempt for metaphysics which is not scientifically informed. I agree with him. Extreme thought experiments are worth considering, but impossible ones are pointless. |
| 16258 | To get an ontology from ontological commitment, just add that some theory is actually true [Maudlin] |
| Full Idea: The doctrine of ontological commitment becomes a central element in a theory of ontology if one merely adds that a particular theory is, in fact, true | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 3.1) | |
| A reaction: Helpful. I don't think the truth of a theory entails the actual existence of every component mentioned in the theory, as some of them may be generalisations, abstractions, vague, or even convenient linking fictions. |
| 16259 | Naïve translation from natural to formal language can hide or multiply the ontology [Maudlin] |
| Full Idea: Naïve translation from natural language into formal language can obscure necessary ontology as easily as it can create superfluous ontological commitment. …The lion's share of metaphysical work is done when settling on the right translation. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 3.1) | |
| A reaction: I suspect this is more than a mere problem of 'naivety', but may be endemic to the whole enterprise. If you hammer a square peg into a round hole, you expect to lose something. Language is subtle, logic is crude. |
| 16253 | A property is fundamental if two objects can differ in only that respect [Maudlin] |
| Full Idea: Fragility is not a fundamental physical property, in that two pieces of glass cannot be physically identical save for their fragility. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 2.5) | |
| A reaction: Nice. The best idea I have found in Maudlin, so far! This gives a very nice test for picking out the fundamental physical and intrinsic properties. |
| 16263 | Fundamental physics seems to suggest there are no such things as properties [Maudlin] |
| Full Idea: If one believes that fundamental physics is the place to look for the truths about universals (or tropes or natural sets), then one may find that physics is telling us there are no such things. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 3.2) | |
| A reaction: His prior discussion of quantum chromodynamics suggests, to me, merely that properties can be described in terms of vectors etc., and remains neutral on the ontology - but then I am blinded by science. |
| 16260 | Existence of universals may just be decided by acceptance, or not, of second-order logic [Maudlin] |
| Full Idea: On one line of thought, the question of whether universals exist seems to reduce to the question of the utility, or necessity, of using second-order rather than first-order logic. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 3.1) | |
| A reaction: Second-order logic quantifies over properties, where first-order logic just quantifies over objects. This is an extreme example of doing your metaphysics largely through logic. Not my approach. |
| 16277 | Logically impossible is metaphysically impossible, but logically possible is not metaphysically possible [Maudlin] |
| Full Idea: While logical impossibility is a species of metaphysical impossibility, logical possibility is not a species of metaphysical possibility. The logically impeccable description 'Cicero was not Tully' describes a metaphysically impossible situation. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 7 Epilogue) | |
| A reaction: The context of this is Maudlin attack on daft notions of metaphysical possibility that are at variance with the limits set by science, but he is still conceding that there are types of metaphysical modality. |
| 16249 | A counterfactual antecedent commands the redescription of a selected moment [Maudlin] |
| Full Idea: The purpose of the antecedent of a counterfactual is to provide instructions on how to pick a Cauchy surface (pick a moment in time) and how to generate an altered description of that moment. It is more of a command than an indicative sentence. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 1.5) | |
| A reaction: Quite plausible, but the antecedent might contain no description. 'If things had gone differently, we wouldn't be in this mess'. The antecedent might be timeless. 'If pigs had wings, they still wouldn't fly'. |
| 16254 | Induction leaps into the unknown, but usually lands safely [Maudlin] |
| Full Idea: Induction is always a leap beyond the known, but we are constantly assured by later experience that we have landed safely. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 2.5) | |
| A reaction: Not philosophically very interesting, but a nice remark for capturing the lived aspect of inductive thought, as practised by the humblest of animals. |
| 16245 | Laws should help explain the things they govern, or that manifest them [Maudlin] |
| Full Idea: A law ought to be capable of playing some role in explaining the phenomena that are governed by or are manifestations of it. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 1.2) | |
| A reaction: I find this attitude bewildering. 'Why do electrons have spin?' 'Because they all do!' The word 'governed' is the clue. What on earth is a law, if it can 'govern' nature? What is its ontological status? Natures of things are basic, not 'laws'. |
| 16248 | Evaluating counterfactuals involves context and interests [Maudlin] |
| Full Idea: The evaluation of counterfactual claims is widely recognised as being influenced by context and interest. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 1.5) | |
| A reaction: Such evaluation certainly seems to involve imagination, and so the pragmatics can creep in there. I don't quite see why it should be deeply contextual. |
| 16250 | We don't pick a similar world from many - we construct one possibility from the description [Maudlin] |
| Full Idea: It seems unlikely the psychological process could mirror Lewis's semantics: people don't imagine a multiplicity of worlds and the pick out the most similar. Rather we construct representations of possible worlds from counterfactual descriptions. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 1.5) | |
| A reaction: I approve of fitting such theories into a psychology, but this may be unfair to Lewis, who aims for a logical model, not an account of how we actually approach the problem. |
| 16268 | The counterfactual is ruined if some other cause steps in when the antecedent fails [Maudlin] |
| Full Idea: A counterexample to the counterfactual approach is that perhaps the effect would have occurred despite the absence of the cause since another cause would have stepped in to bring it about. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 5) | |
| A reaction: …Hence you cannot say 'if C had not occurred, E would definitely not have occurred'. You have to add 'ceteris paribus', which ruins the neatness of the theory. |
| 16267 | If we know the cause of an event, we seem to assent to the counterfactual [Maudlin] |
| Full Idea: When we think we know the cause of an event, we typically assent to the corresponding Hume counterfactual. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 5) | |
| A reaction: This is the correct grounding of the counterfactual approach - not that we think counterfactuals are causation, but that knowledge of causation will map neatly onto a network of counterfactuals, thus providing a logic for the whole process. |
| 16269 | If the effect hadn't occurred the cause wouldn't have happened, so counterfactuals are two-way [Maudlin] |
| Full Idea: If Kennedy had still been President in Dec 1963, he would not have been assassinated in Nov 1963, so the counterfactual goes both ways (where the cause seems to only go one way). | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 5) | |
| A reaction: Maudlin says a lot of fine-tuning has sort of addressed these problems, but that counterfactual causation is basically wrong-headed anyway, and I incline to agree, though one must understand what the theory is (and is not) trying to do. |
| 16247 | Laws are primitive, so two indiscernible worlds could have the same laws [Maudlin] |
| Full Idea: Laws are ontologically primitives at least in that two worlds could differ in their laws but not in any observable respect. ….[21] I take content of the laws to be expressed by equations. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 1.4) | |
| A reaction: At least that spells out his view fairly dramatically, but I am baffled as to what he thinks a law could be. He is arguing against the Lewis regularity-axioms view, and the Armstrong universal-relations view. He ignores the essentialist view. |
| 16272 | Fundamental laws say how nature will, or might, evolve from some initial state [Maudlin] |
| Full Idea: The fundamental laws of nature appear to be laws of temporal evolution: they specify how the state of the universe will, or might, evolve from a given intial state. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 6) | |
| A reaction: Maudlin takes both laws of nature and the passage of time to be primitive facts, and this is how they are connected. I think (this week) that I take time and causation to be primitive, but not laws. |
| 16242 | Laws of nature are ontological bedrock, and beyond analysis [Maudlin] |
| Full Idea: The laws of nature stand in no need of 'philosophical analysis'; they ought to be posited as ontological bedrock. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], Intro) | |
| A reaction: This is Maudlin's most basic principle, and I don't agree with it. The notion that laws are more deeply embedded in reality than the physical stuff they control is a sort of 'law-mysticism' that needs to be challenged. |
| 16251 | 'Humans with prime house numbers are mortal' is not a law, because not a natural kind [Maudlin] |
| Full Idea: 'All humans who live in houses with prime house numbers are mortal' is not a law because the class referred to is not a natural kind. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 1.6) | |
| A reaction: Maudlin wants laws to be primitive, but he now needs a primitive notion of a natural kind to make it work. If kinds generate laws, you can ditch the laws, and build your theory on the kinds. He also says no death is explained by 'all humans are mortal'. |
| 16270 | If laws are just regularities, then there have to be laws [Maudlin] |
| Full Idea: On the Mill-Ramsey-Lewis account of laws, I take it that if the world is extensive and variegated enough, then there must be laws. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 5.2) | |
| A reaction: A nice point. If there is any sort of pattern discernible in the surface waves on the sea, then there must be a law to cover it, not matter how vague or complex. |
| 16264 | I believe the passing of time is a fundamental fact about the world [Maudlin] |
| Full Idea: I believe that it is a fundamental, irreducible fact about the spatio-temporal structure of the world that time passes. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 4) | |
| A reaction: Worth quoting because it comes from a philosopher fully informed about, and heavily committed to, the physicist's approach to reality. One fears that physicists steeped in Einstein are all B-series Eternalists. Get a life! |
| 16265 | If time passes, presumably it passes at one second per second [Maudlin] |
| Full Idea: It is necessary and, I suppose, a priori that if time passes at all it passes at one second per second. …Similarly, the fair exchange rate for a dollar must be a dollar. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 4.1) | |
| A reaction: [He is discussing Huw Price on time] This is a reply to the claim that if time passes it has to pass at some rate, and 'one second per second' is ridiculous. Not very convincing, even with the dollar analogy. |
| 16266 | There is one ordered B series, but an infinitude of A series, depending on when the present is [Maudlin] |
| Full Idea: Given events ordered in a B series, one defines an infinitude of different A series that correspond to taking different events as 'now' or 'present'. McTaggart talks of 'the A series' when there is an infinitude of such. | |
| From: Tim Maudlin (The Metaphysics within Physics [2007], 4.3 n11) | |
| A reaction: This strikes me as a rather mathematical (and distorted) claim about the A series view. The A-series is one dynamic happening. Not an infinity of static times lines, each focused on a different 'now'. |