24 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. |
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) |
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. |
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) |
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. |
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. |
7440 | Secondary qualities are microscopic primary qualities of physical things [Armstrong] |
Full Idea: I argue for the direct identification of the secondary qualities with microscopic primary qualities of physical things. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xxii) | |
A reaction: This sounds a bit like the eliminativism which Armstrong rejects. This seems in danger of mixing questions about the nature of mental events with questions about the nature of externally perceived objects. |
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? |
7437 | Consciousness and experience of qualities are not the same [Armstrong] |
Full Idea: Consciousness and experience of qualities are often run together - a serious mistake, I think. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvii) | |
A reaction: A difficult claim to evaluate. Can we experience redness without being conscious of it? Could there be consciousness (e.g. of concepts) which didn't involve any qualities? I suspect that qualities are more basic than intentionality or consciousness. |
7434 | Behaviourism is false, but mind is definable as the cause of behaviour [Armstrong] |
Full Idea: Behaviourism is false, but one is not far from the truth if one defines the mind as the cause of behaviour. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvi) | |
A reaction: As Putnam says, if you cut all the efferent (outgoing) nerves, you would have a mind with no behaviour at all. I would say my mind is full of stuff that never affects my behaviour. However, influencing behaviour is certainly the main function of a mind. |
7436 | The manifestations of a disposition need never actually exist [Armstrong] |
Full Idea: The manifestations of a disposition have the particularly mysterious property (metaphysically speaking) that they need not exist - which makes them rather like intentional objects. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvii) | |
A reaction: His example is a brittle glass which never shatters. This problem seems to require the mention of conditional and counterfactual statements in the description of the actual world, which rather increases the workload for philosophers. |
7429 | Causal Functionalism says mental states are apt for producing behaviour [Armstrong] |
Full Idea: I speak of my view as the Causal version of functionalism, which asserts that mental states are states apt for the production of certain ranges of behaviour and, in some cases, apt for being produced by certain ranges of stimuli. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xiv) | |
A reaction: This effectively makes a mental state a place in a flowdiagram (and hence the mind is software). It says nothing about what qualities the mental states have which make them apt for this role. Full explanations need more than the function. |
7438 | A causal theory of mentality would be improved by a teleological element [Armstrong] |
Full Idea: I now think, following Lycan, that my Causal theory of mentality would be strengthened (perhaps eliminating some potential counter-examples) by the addition of a teleological element. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xviii) | |
A reaction: For Lycan, see Idea 6533. Armstrong has begun to realise that merely specifying the causal role of a mental state is too thin as an explanation. Teleology widens the notion of function. I also want to know about the properties that make it possible. |
7431 | The identity of mental states with physical properties is contingent, because the laws of nature are contingent [Armstrong] |
Full Idea: Granted the contingency of the laws of nature, the identification of dispositions with their categorical bases can be contingent only. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xvi) | |
A reaction: Personally I am not willing to grant the contingency of the laws of nature, but I suppose Armstrong is right about identity if he is right about laws. Presumably an identity could happen to be invariant across possible worlds, without being necessary. |
7432 | One mental role might be filled by a variety of physical types [Armstrong] |
Full Idea: If the mental is just that which plays a causal role then there is the possibility, which may even be an empirical possibility, that the causal role of tokens of the same mental type should be filled by tokens of significantly different physical types. | |
From: David M. Armstrong (Pref to new 'Materialist Theory' [1992], p.xiv) | |
A reaction: This allows for multiple realisability in a physicalist framework. Fear has the same role in all animals, but may be realised in physically different ways. I go further, and say that two mental states could differ, while playing the same role. |
4316 | Either all action is rational, or reason dominates, or reason is only concerned with means [Cottingham] |
Full Idea: We can distinguish rational exclusivism (all activity is guided by reason - Plato and Spinoza), rational hegemonism (all action is dominated by reason), and rational instrumentalism (reason assesses means rather than ends - Hume). | |
From: John Cottingham (Reason, Emotions and Good Life [2000]) | |
A reaction: The idea that reason is the only cause of actions seems deeply implausible, but I strongly resist Hume's instrumental approach. Action without desire is not a contradiction. |
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. |