33 ideas
| 16477 | Asserting not-p is saying p is false [Russell] |
| Full Idea: When you do what a logician would call 'asserting not-p', you are saying 'p is false'. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: This is presumably classical logic. If we could label p as 'undetermined' (a third truth value), then 'not-p' might equally mean 'undetermined'. |
| 16484 | There are four experiences that lead us to talk of 'some' things [Russell] |
| Full Idea: Propositions about 'some' arise, in practice, in four ways: as generalisations of disjunctions; when an instance suggests compatibility of terms we thought incompatible; as steps to a generalisation; and in cases of imperfect memory. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: Modern logicians seem to have no interest in the question Russell is investigating here, but I love his attempt, however vague the result, to connect logic to real experience and thought. |
| 11211 | If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt] |
| Full Idea: If a designated conclusion follows from the premisses, but the argument involves two howlers which cancel each other out, then the moral is that the path an argument takes from premisses to conclusion does matter to its logical evaluation. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], II) | |
| A reaction: The drift of this is that our view of logic should be a little closer to the reasoning of ordinary language, and we should rely a little less on purely formal accounts. |
| 16486 | The physical world doesn't need logic, but the mental world does [Russell] |
| Full Idea: The non-mental world can be completely described without the use of any logical word, …but when it comes to the mental world, there are facts which cannot be mentioned without the use of logical words. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: He adds that logical words are not needed for physics, but are needed for psychology. I love Russell's interest in the psychology of logic (in defiance of the anti-psychologism of Frege). See also the ideas of Robert Hanna. |
| 2947 | Questions wouldn't lead anywhere without the law of excluded middle [Russell] |
| Full Idea: Without the law of excluded middle, we could not ask the questions that give rise to discoveries. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], c.p.88) |
| 11212 | The sense of a connective comes from primitively obvious rules of inference [Rumfitt] |
| Full Idea: A connective will possess the sense that it has by virtue of its competent users' finding certain rules of inference involving it to be primitively obvious. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], III) | |
| A reaction: Rumfitt cites Peacocke as endorsing this view, which characterises the logical connectives by their rules of usage rather than by their pure semantic value. |
| 11210 | Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt] |
| Full Idea: If 'and' and 'but' really are alike in sense, in what might that likeness consist? Some philosophers of classical logic will reply that they share a sense by virtue of sharing a truth table. | |
| From: Ian Rumfitt ("Yes" and "No" [2000]) | |
| A reaction: This is the standard view which Rumfitt sets out to challenge. |
| 16483 | Disjunction may also arise in practice if there is imperfect memory. [Russell] |
| Full Idea: Another situation in which a disjunction may arise is practice is imperfect memory. 'Either Brown or Jones told me that'. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) |
| 16480 | A disjunction expresses indecision [Russell] |
| Full Idea: A disjunction is the verbal expression of indecision, or, if a question, of the desire to reach a decision. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: Russell is fishing here for Grice's conversational implicature. If you want to assert a simple proposition, you don't introduce it into an irrelevant disjunction, because that would have a particular expressive purpose. |
| 16479 | 'Or' expresses hesitation, in a dog at a crossroads, or birds risking grabbing crumbs [Russell] |
| Full Idea: Psychologically, 'or' corresponds to a state of hesitation. A dog waits at a fork in the road, to see which way you are going. For crumbs on a windowsill, birds behave in a manner we would express by 'shall I be brave, or go hungry?'. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: I love two facts here - first, that Russell wants to link the connective to the psychology of experience, and second, that a great logician wants to connect his logic to the minds of animals. |
| 16481 | 'Or' expresses a mental state, not something about the world [Russell] |
| Full Idea: When we assert 'p or q' we are in a state which is derivative from two previous states, and we express this state, not something about the world. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: His example: at a junction this road or that road goes to Oxford, but the world only contains the roads, not some state of 'this or that road'. He doesn't deny that in one sense 'p or q' tells you something about the world. |
| 16487 | Maybe the 'or' used to describe mental states is not the 'or' of logic [Russell] |
| Full Idea: It might be contended that, in describing what happens when a man believes 'p or q', the 'or' that we must use is not the same as the 'or' of logic. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: This seems to be the general verdict on Russell's enquiries in this chapter, but I love any attempt, however lacking in rigour etc., to connect formal logic to how we think, and thence to the world. |
| 8525 | Relations need terms, so they must be second-order entities based on first-order tropes [Campbell,K] |
| Full Idea: Because there cannot be relations without terms, in a meta-physic that makes first-order tropes the terms of all relations, relational tropes must belong to a second, derivative order. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §8) | |
| A reaction: The admission that there could be a 'derivative order' may lead to trouble for trope theory. Ostrich Nominalists could say that properties themselves are derivative second-order abstractions from indivisible particulars. Russell makes them first-order. |
| 16475 | A 'heterological' predicate can't be predicated of itself; so is 'heterological' heterological? Yes=no! [Russell] |
| Full Idea: A predicate is 'heterological' when it cannot be predicated of itself; thus 'long' is heterological because it is not a long word, but 'short' is homological. So is 'heterological' heterological? Either answer leads to a contradiction. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: [Grelling's Paradox] Yes: 'heterological' is heterological because it isn't heterological; No: it isn't, because it is. Russell says we therefore need a hierarchy of languages (types), and the word 'word' is outside the system. |
| 8518 | Events are trope-sequences, in which tropes replace one another [Campbell,K] |
| Full Idea: Events are widely acknowledged to be particulars, but they are plainly not ordinary concrete particulars. They are best viewed as trope-sequences, in which one condition gives way to another. They are changes in which tropes replace one another. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §3) | |
| A reaction: If nothing exists except bundles of tropes, it is worth asking WHY one trope would replace another. Some tropes are active (i.e. they are best described as 'powers'). |
| 8513 | Two red cloths are separate instances of redness, because you can dye one of them blue [Campbell,K] |
| Full Idea: If we have two cloths of the very same shade of redness, we can show there are two cloths by burning one and leaving the other unaffected; we show there are two cases of redness in the same way: dye one blue, leaving the other unaffected. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §1) | |
| A reaction: This has to be one of the basic facts of the problem accepted by everyone. If you dye half of one of the pieces, was the original red therefore one instance or two? Has it become two? How many red tropes are there in a red cloth? |
| 8514 | Red could only recur in a variety of objects if it was many, which makes them particulars [Campbell,K] |
| Full Idea: If there are a varied group of red objects, the only element that recurs is the colour. But it must be the colour as a particular (a 'trope') that is involved in the recurrence, for only particulars can be many in the way required for recurrence. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §1) | |
| A reaction: This claim seems to depend on the presupposition that rednesses are countable things, but it is tricky trying to count the number of blue tropes in the sky. |
| 8522 | Tropes solve the Companionship Difficulty, since the resemblance is only between abstract particulars [Campbell,K] |
| Full Idea: The 'companionship difficulty' cannot arise if the members of the resemblance class are tropes rather than whole concrete particulars. The instances of having a heart, as abstract particulars, are quite different from instances of having a kidney. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §6) | |
| A reaction: The companionship difficulty seems worst if you base your account of properties just on being members of a class. Any talk of resemblance eventually has to talk about 'respects' of resemblance. Is a trope a respect? Is a mode an object? |
| 8523 | Tropes solve the Imperfect Community problem, as they can only resemble in one respect [Campbell,K] |
| Full Idea: The 'problem of imperfect community' cannot arise where our resemblance sets are sets of tropes. Tropes, by their very nature and mode of differentiation can only resemble in one respect. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §6) | |
| A reaction: You arrive at very different accounts of what resemblance means according to how you express the problem verbally. We can only find a solution through thinking which transcends language. Heresy! |
| 8524 | Trope theory makes space central to reality, as tropes must have a shape and size [Campbell,K] |
| Full Idea: The metaphysics of abstract particulars gives a central place to space, or space-time, as the frame of the world. ...Tropes are, of their essence, regional, which carries with it the essential presence of shape and size in any trope occurrence. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §7) | |
| A reaction: Trope theory has a problem with Aristotle's example (Idea 557) of what happens when white is mixed with white. Do two tropes become one trope if you paint on a second coat of white? How can particulars merge? How can abstractions merge? |
| 8521 | Nominalism has the problem that without humans nothing would resemble anything else [Campbell,K] |
| Full Idea: The objection to nominalism is its consequence that if there were no human race (or other living things), nothing would be like anything else. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §6) | |
| A reaction: Anti-realists will be unflustered by this difficulty. Personally it strikes me as obvious that some aspects of resemblance are part of reality which we did not contribute. This I take to be a contingent fact, founded on the existence of natural kinds. |
| 8515 | Tropes are basic particulars, so concrete particulars are collections of co-located tropes [Campbell,K] |
| Full Idea: If tropes are basic particulars, then concrete particulars count as dependent realities. They are collections of co-located tropes, depending on these tropes as a fleet does upon its component ships. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §2) | |
| A reaction: If I sail my yacht through a fleet, do I become part of it? Presumably trope theory could avoid a bundle view of objects. A bare substratum could be a magnet which attracts tropes. |
| 8519 | Bundles must be unique, so the Identity of Indiscernibles is a necessity - which it isn't! [Campbell,K] |
| Full Idea: Each individual is distinct from each other individual, so the bundle account of objects requires each bundle to be different from every other bundle. So the Identity of Indiscernibles must be a necessary truth, which, unfortunately, it is not. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §5) | |
| A reaction: Clearly the Identity of Indiscernibles is not a necessary truth (consider just two identical spheres). Location and time must enter into it. Could we not add a further individuation requirement to the necessary existence of a bundle? (Quinton) |
| 4033 | Two pure spheres in non-absolute space are identical but indiscernible [Campbell,K] |
| Full Idea: The Identity of Indiscernibles is not a necessary truth. It fails in possible worlds where there are two identical spheres in a non-absolute space, or worlds without beginning or end where events are exactly cyclically repeated. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §5) | |
| A reaction: The principle was always very suspect, and these seem nice counterexamples. As so often, epistemology and ontology had become muddled. |
| 16482 | All our knowledge (if verbal) is general, because all sentences contain general words [Russell] |
| Full Idea: All our knowledge about the world, in so far as it is expressed in words, is more or less general, because every sentence contains at least one word that is not a proper name, and all such words are general. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: I really like this, especially because it addresses the excessive reliance of some essentialists on sortals, categories and natural kinds, instead of focusing on the actual physical essences of individual objects. |
| 4758 | Naïve realism leads to physics, but physics then shows that naïve realism is false [Russell] |
| Full Idea: Naïve realism leads to physics, and physics, if true, shows that naïve realism is false. Therefore naïve realism, if true, is false, therefore it is false. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], p.13) | |
| A reaction: I'm inclined to agree with this, though once you have gone off and explored representation and sense data you may be driven back to naïve realism again. |
| 16476 | For simple words, a single experience can show that they are true [Russell] |
| Full Idea: So long as a man avoids words which are condensed inductions (such as 'dog'), and confines himself to words that can describe a single experience, it is possible for a single experience to show that his words are true. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: One might question whether a line can be drawn between the inductive and the non-inductive in this way. I'm inclined just to say that the simpler the proposition the less room there is for error in confirming it. |
| 16485 | Perception can't prove universal generalisations, so abandon them, or abandon empiricism? [Russell] |
| Full Idea: Propositions about 'some' may be proved empirically, but propositions about 'all' are difficult to know, and can't be proved unless such propositions are in the premisses. These aren't in perception, so forgo general propositions, or abandon empiricism? | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: This is obviously related to the difficulty empiricists have with induction. You could hardly persuade logicians to give up the universal quantifier, because it is needed in mathematics. Do we actually know any universal empirical truths? |
| 8512 | Abstractions come before the mind by concentrating on a part of what is presented [Campbell,K] |
| Full Idea: An item is abstract if it is got before the mind by an act of abstraction, that is, by concentrating attention on some, but not all, of what is presented. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §1) | |
| A reaction: I think this point is incredibly important. Pure Fregean semantics tries to leave out the psychological component, and yet all the problems in semantics concern various sorts of abstraction. Imagination is the focus of the whole operation. |
| 11214 | We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt] |
| Full Idea: The standard view is that affirming not-A is more complex than affirming the atomic sentence A itself, with the latter determining its sense. But we could learn 'not' directly, by learning at once how to either affirm A or reject A. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], IV) | |
| A reaction: [compressed] This seems fairly anti-Fregean in spirit, because it looks at the psychology of how we learn 'not' as a way of clarifying what we mean by it, rather than just looking at its logical behaviour (and thus giving it a secondary role). |
| 16478 | A mother cat is paralysed if equidistant between two needy kittens [Russell] |
| Full Idea: I once, to test the story of Buridan's Ass, put a cat exactly half-way between her two kittens, both too young to move: for a time she found the disjunction paralysing. | |
| From: Bertrand Russell (An Inquiry into Meaning and Truth [1940], 5) | |
| A reaction: Buridan's Ass is said to have starved between two equal piles of hay. Reason can't be the tie-breaker; reason obviously says 'choose one!', but intellectualism demands a reason for the one you choose. |
| 8517 | Causal conditions are particular abstract instances of properties, which makes them tropes [Campbell,K] |
| Full Idea: The conditions in causal statements are usually particular cases of properties. A collapse results from the weakness of this cable (not any other). This is specific to a time and place; it is an abstract particular. It is, in short, a trope. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §3) | |
| A reaction: The fan of universals could counter this by saying that the collapse results from this unique combination of universals. Resemblance nominalist can equally build an account on the coincidence of certain types of concrete particulars. |
| 8516 | Davidson can't explain causation entirely by events, because conditions are also involved [Campbell,K] |
| Full Idea: Not all singular causal statements are of Davidson's event-event type. Many involve conditions, so there are condition-event (weakness/collapse), event-condition (explosion/movement), and condition-condition (hot/warming) causal connections. | |
| From: Keith Campbell (The Metaphysic of Abstract Particulars [1981], §3) | |
| A reaction: Fans of Davidson need to reduce conditions to events. The problem of individuation keeps raising its head. Davidson makes it depend on description. Kim looks good, because events, and presumably conditions, reduce to something small and precise. |