Combining Texts

All the ideas for 'Thinking About Mathematics', 'Mathematics: Form and Function' and 'Philosophical Investigations'

unexpand these ideas     |    start again     |     specify just one area for these texts


69 ideas

1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
Philosophy is a battle against the bewitchment of our intelligence by means of language [Wittgenstein]
     Full Idea: Philosophical problems are solved, not by giving new information, but by arranging what we have already known. Philosophy is a battle against the bewitchment of our intelligence by means of language.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §109), quoted by Jerrold J. Katz - Realistic Rationalism Int.xi
     A reaction: A philosophical dispute can be settled by a piece of information, which may be already known to you, but new to me. Philosophical discussion can also point to a scientific research programme - i.e. a need for new information. I like the first sentence.
1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
What is your aim in philosophy? - To show the fly the way out of the fly-bottle [Wittgenstein]
     Full Idea: What is your aim in philosophy? - To show the fly the way out of the fly-bottle.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §309)
     A reaction: Ridiculous. Trying to think about thought is not a pointless buzzing - it is an attempt by humans to become like gods.
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Bring words back from metaphysics to everyday use [Wittgenstein]
     Full Idea: What we do is to bring words back from their metaphysical to their everyday use.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], 116), quoted by Philippa Foot - Natural Goodness 7 n16
     A reaction: A germ of ordinary language philosophy. It is wrong to think that metaphysics must be studied in the usages of ordinary language, but I strongly believe that words like 'essence' or 'objectivity' should retain their normal meaning when philosophising.
2. Reason / B. Laws of Thought / 3. Non-Contradiction
The problem is to explain the role of contradiction in social life [Wittgenstein]
     Full Idea: When a contradiction appears, we say: "I didn't mean it like that"; the civil status of a contradiction, or its status in civil life: there is the philosophical problem.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §125), quoted by Robert Fogelin - Walking the Tightrope of Reason Ch.2
     A reaction: The point is that logical concepts such as contradiction are conventional, and not all-or-nothing, so we might agree that you didn't really contradict yourself (when perhaps you uttered a witty ironic paradox). I don't see the problem as philosophical.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
ZFC could contain a contradiction, and it can never prove its own consistency [MacLane]
     Full Idea: We have at hand no proof that the axioms of ZFC for set theory will never yield a contradiction, while Gödel's second theorem tells us that such a consistency proof cannot be conducted within ZFC.
     From: Saunders MacLane (Mathematics: Form and Function [1986], p.406), quoted by Penelope Maddy - Naturalism in Mathematics
     A reaction: Maddy quotes this, while defending set theory as the foundation of mathematics, but it clearly isn't the most secure foundation that could be devised. She says the benefits of set theory do not need guaranteed consistency (p.30).
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro]
     Full Idea: Intuitionists in mathematics deny excluded middle, because it is symptomatic of faith in the transcendent existence of mathematical objects and/or the truth of mathematical statements.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2)
     A reaction: There are other problems with excluded middle, such as vagueness, but on the whole I, as a card-carrying 'realist', am committed to the law of excluded middle.
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
Wittgenstein says we want the grammar of problems, not their first-order logical structure [Wittgenstein, by Horsten/Pettigrew]
     Full Idea: For the later Wittgenstein what we should be after is the grammatical structure of philosophical problems, not the first-order logical structure of such problems.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Horsten,L/Pettigrew,R - Mathematical Methods in Philosophy 2
     A reaction: This is the most sympathetic spin I have ever seen put on the apparent rather anti-philosophical later Wittgenstein. I nurse doubts about highly formal approaches to philosophy, and maybe 'grammar' (whatever that is) is our target.
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
Naming is a preparation for description [Wittgenstein]
     Full Idea: Naming is a preparation for description.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §049)
     A reaction: Something has to be the starting point for a description. And yet a description could turn out to be an elaborate name.
5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive
A name is not determined by a description, but by a cluster or family [Wittgenstein, by Kripke]
     Full Idea: According to Wittgenstein (and Searle) the referent of a name is determined not by a single description but by some cluster or family.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952], §079) by Saul A. Kripke - Naming and Necessity lectures Lecture 1
     A reaction: It is because of this characteristically woolly, indeterminate and relativist view of Wittgenstein that I (and most people) find Kripke's notion of a 'baptism' so refreshing. It cuts throught the fog of language, and connects to reality.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro]
     Full Idea: It is surely wise to identify the positions in the natural numbers structure with their counterparts in the integer, rational, real and complex number structures.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2)
     A reaction: The point is that this might be denied, since 3, 3/1, 3.00.., and -3*i^2 are all arrived at by different methods of construction. Natural 3 has a predecessor, but real 3 doesn't. I agree, intuitively, with Shapiro. Russell (1919) disagreed.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / h. Reals from Cauchy
Cauchy gave a formal definition of a converging sequence. [Shapiro]
     Full Idea: A sequence a1,a2,... of rational numbers is 'Cauchy' if for each rational number ε>0 there is a natural number N such that for all natural numbers m, n, if m>N and n>N then -ε < am - an < ε.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 7.2 n4)
     A reaction: The sequence is 'Cauchy' if N exists.
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Categories are the best foundation for mathematics [Shapiro]
     Full Idea: There is a dedicated contingent who hold that the category of 'categories' is the proper foundation for mathematics.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.3 n7)
     A reaction: He cites Lawvere (1966) and McLarty (1993), the latter presenting the view as a form of structuralism. I would say that the concept of a category will need further explication, and probably reduce to either sets or relations or properties.
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / f. Zermelo numbers
Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro]
     Full Idea: Zermelo said that for each number n, its successor is the singleton of n, so 3 is {{{null}}}, and 1 is not a member of 3. Von Neumann said each number n is the set of numbers less than n, so 3 is {null,{null},{null,{null}}}, and 1 is a member of 3.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2)
     A reaction: See Idea 645 - Zermelo could save Plato from the criticisms of Aristotle! These two accounts are cited by opponents of the set-theoretical account of numbers, because it seems impossible to arbitrate between them.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Numbers do not exist independently; the essence of a number is its relations to other numbers [Shapiro]
     Full Idea: The structuralist vigorously rejects any sort of ontological independence among the natural numbers; the essence of a natural number is its relations to other natural numbers.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1)
     A reaction: This seems to place the emphasis on ordinals (what order?) rather than on cardinality (how many?). I am strongly inclined to think that this is the correct view, though you can't really have relations if there is nothing to relate.
A 'system' is related objects; a 'pattern' or 'structure' abstracts the pure relations from them [Shapiro]
     Full Idea: A 'system' is a collection of objects with certain relations among them; a 'pattern' or 'structure' is the abstract form of a system, highlighting the interrelationships and ignoring any features they do not affect how they relate to other objects.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1)
     A reaction: Note that 'ignoring' features is a psychological account of abstraction, which (thanks to Frege and Geach) is supposed to be taboo - but which I suspect is actually indispensable in any proper account of thought and concepts.
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Logicism seems to be a non-starter if (as is widely held) logic has no ontology of its own [Shapiro]
     Full Idea: The thesis that principles of arithmetic are derivable from the laws of logic runs against a now common view that logic itself has no ontology. There are no particular logical objects. From this perspective logicism is a non-starter.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 5.1)
     A reaction: This criticism strikes me as utterly devastating. There are two routes to go: prove that logic does have an ontology of objects (what would they be?), or - better - deny that arithmetic contains any 'objects'. Or give up logicism.
6. Mathematics / C. Sources of Mathematics / 7. Formalism
Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro]
     Full Idea: Term Formalism is the view that mathematics is just about characters or symbols - the systems of numerals and other linguistic forms. ...This will cover integers and rational numbers, but what are real numbers supposed to be, if they lack names?
     From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.1)
     A reaction: Real numbers (such as pi and root-2) have infinite decimal expansions, so we can start naming those. We could also start giving names like 'Harry' to other reals, though it might take a while. OK, I give up.
Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro]
     Full Idea: Game Formalism likens mathematics to chess, where the 'content' of mathematics is exhausted by the rules of operating with its language. ...This, however, leaves the problem of why the mathematical games are so useful to the sciences.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.2)
     A reaction: This thought pushes us towards structuralism. It could still be a game, but one we learned from observing nature, which plays its own games. Chess is, after all, modelled on warfare.
Deductivism says mathematics is logical consequences of uninterpreted axioms [Shapiro]
     Full Idea: The Deductivist version of formalism (sometimes called 'if-thenism') says that the practice of mathematics consists of determining logical consequences of otherwise uninterpreted axioms.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 6.2)
     A reaction: [Hilbert is the source] More plausible than Term or Game Formalism (qv). It still leaves the question of why it seems applicable to nature, and why those particular axioms might be chosen. In some sense, though, it is obviously right.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro]
     Full Idea: Critics commonly complain that the intuitionist restrictions cripple the mathematician. On the other hand, intuitionist mathematics allows for many potentially important distinctions not available in classical mathematics, and is often more subtle.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 7.1)
     A reaction: The main way in which it cripples is its restriction on talk of infinity ('Cantor's heaven'), which was resented by Hilbert. Since high-level infinities are interesting, it would be odd if we were not allowed to discuss them.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / c. Conceptualism
Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro]
     Full Idea: I classify conceptualists according to what they say about properties or concepts. If someone classified properties as existing independent of language I would classify her as a realist in ontology of mathematics. Or they may be idealists or nominalists.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 2.2.1)
     A reaction: In other words, Shapiro wants to eliminate 'conceptualist' as a useful label in philosophy of mathematics. He's probably right. All thought involves concepts, but that doesn't produce a conceptualist theory of, say, football.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
'Impredicative' definitions refer to the thing being described [Shapiro]
     Full Idea: A definition of a mathematical entity is 'impredicative' if it refers to a collection that contains the defined entity. The definition of 'least upper bound' is impredicative as it refers to upper bounds and characterizes a member of this set.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2)
     A reaction: The big question is whether mathematics can live with impredicative definitions, or whether they threaten to be viciously circular, and undermine the whole enterprise.
9. Objects / D. Essence of Objects / 5. Essence as Kind
Essence is expressed by grammar [Wittgenstein]
     Full Idea: Essence is expressed by grammar. ...Grammar tells us what kind of object anything is.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §371-3)
     A reaction: Enigmatic, as usual. The second part seems to imply sortal essentialism, though the emphasis on grammar seems to make it highly conventional, rather than a reflection of 'real' sorts.
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
The belief that fire burns is like the fear that it burns [Wittgenstein]
     Full Idea: The belief that fire will burn me is of the same kind as the fear that it will burn me.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §473)
     A reaction: Most of our beliefs are forced on us, rather than chosen, and this nice remark gives an indication of the reason. It dovetails with Peirce's pragmatic approach to be belief (e.g. Idea 6598), which is well developed by Robert Fogelin.
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
Are sense-data the material of which the universe is made? [Wittgenstein]
     Full Idea: Are sense-data the material of which the universe is made?
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §401)
     A reaction: Presumably the question is meant to be absurd, and to a realist it is. You can't serious think that a filing cabinet is made of sensations.
12. Knowledge Sources / B. Perception / 4. Sense Data / d. Sense-data problems
As sense-data are necessarily private, they are attacked by Wittgenstein's objections [Wittgenstein, by Robinson,H]
     Full Idea: Sense-data are usually conceived as necessarily private to individual observers, so the final crisis for the empiricist conception of perception was Wittgenstein's famous polemic against such private objects.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Howard Robinson - Perception IV.1
     A reaction: Personally I remain unconvinced by Wittgenstein's very elusive argument, but I think there are plenty of other reasons for doubting whether the idea of sense-data throws much light on our understanding of the processes of perception.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Rationalism tries to apply mathematical methodology to all of knowledge [Shapiro]
     Full Idea: Rationalism is a long-standing school that can be characterized as an attempt to extend the perceived methodology of mathematics to all of knowledge.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 1.1)
     A reaction: Sometimes called 'Descartes's Dream', or the 'Enlightenment Project', the dream of proving everything. Within maths, Hilbert's Programme aimed for the same certainty. Idea 22 is the motto for the opposition to this approach.
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
How do I decide when to accept or obey an intuition? [Wittgenstein]
     Full Idea: If intuition is an inner voice - how do I know how I am to obey it? And how do I know that it doesn't mislead me? For if it can guide me right, it can also guide me wrong. ((Intuition an unnecessary shuffle))
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], 213)
     A reaction: Presumably the last point, in brackets, means that you still have to evaluate the intuition, with which I would agree. I take judgement to occur in the space of reasons, to which intuition is a major contributor. Only a fool would just accept intuition.
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
One can mistrust one's own senses, but not one's own beliefs [Wittgenstein]
     Full Idea: One can mistrust one's own senses, but not one's own beliefs.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], II.x)
     A reaction: This seems right, because we don't choose our beliefs. We don't even choose whether to believe a sensation - we just focus harder until belief does or doesn't occur.
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds
I don't have the opinion that people have minds; I just treat them as such [Wittgenstein]
     Full Idea: My attitude towards him is an attitude towards a soul. I am not of the 'opinion' that he has a soul.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], II.iv)
     A reaction: This seems to be precisely Dennett's 'intentional stance', where we conjure up minds in things like chess-playing computers, irrespective of whether we believe they are conscious.
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / d. Other minds by analogy
It is irresponsible to generalise from my own case of pain to other people's [Wittgenstein]
     Full Idea: If I say of myself that it is only from my own case that I know what the word 'pain' means - must I not say the same of other people too? And how can I generalise from the one case so irresponsibly?
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §293)
     A reaction: This is the best known objection to Mill's Argument from Analogy for other minds. It appears to be induction from a single instance. The better approach seems to be ABduction (best explanation), in which my own case is just some evidence.
To imagine another's pain by my own, I must imagine a pain I don't feel, by one I do feel [Wittgenstein]
     Full Idea: If one has to imagine someone else's pain on the model of one's own, this is none too easy a thing to do: for I have to imagine pain which I do not feel on the model of pain which I do not feel.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §302)
     A reaction: I just don't feel a deep problem here. Wittgenstein didn't know about mirror neurons, which trigger in me a reaction like the one causing your behaviour.
15. Nature of Minds / B. Features of Minds / 3. Privacy
If a lion could talk, we could not understand him [Wittgenstein]
     Full Idea: If a lion could talk, we could not understand him.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], II.xi)
     A reaction: How does he know these things?! We could at least know whether they talked or merely grunted, by studying their correlated behaviour. Cf. dolphins. I think he is wrong. All talk is understandable to a degree, even God's.
If a lion could talk, it would be nothing like other lions [Dennett on Wittgenstein]
     Full Idea: I think that if a lion could talk, that lion would have a mind so different from the general run of lion minds, that although we could understand him just fine, we would learn little about ordinary lions from him.
     From: comment on Ludwig Wittgenstein (Philosophical Investigations [1952], II.xi) by Daniel C. Dennett - Consciousness Explained 14.2
     A reaction: This is rather more sensible than Wittgenstein's famous enigmatic utterance.
16. Persons / C. Self-Awareness / 1. Introspection
To say that I 'know' I am in pain means nothing more than that I AM in pain [Wittgenstein]
     Full Idea: As the word is normally used, it can't be said of me at all that I 'know' I am in pain; what is it supposed to mean - except perhaps that I am in pain?
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §246)
     A reaction: This raises the question of whether self-consciousness implies self-knowledge, and suggests that it doesn't. All our normal talk of knowledge requires some sort of reliable justification of beliefs, and we can't drop that in the case of self-knowledge.
17. Mind and Body / D. Property Dualism / 6. Mysterianism
Why are we not aware of the huge gap between mind and brain in ordinary life? [Wittgenstein]
     Full Idea: Why does the feeling of an unbridgeable gulf between consciousness and brain-process not come into the considerations of our ordinary life?
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §412)
     A reaction: Nice question. Presumably Wittgenstein has a quasi-behaviouristic answer. People don't now ignore it? They retreat into crazy spiritualism.
18. Thought / A. Modes of Thought / 10. Rule Following
An 'inner process' stands in need of outward criteria [Wittgenstein]
     Full Idea: An 'inner process' stands in need of outward criteria.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §580)
     A reaction: Why do processes need 'criteria'? I have never understood why I can't have private criteria, or at least private modifications of public criteria.
Every course of action can either accord or conflict with a rule, so there is no accord or conflict [Wittgenstein]
     Full Idea: Paradox: no course of action could be determined by a rule, because every course of action can be made out to accord with the rule. Answer: if everything can accord with the rule, then everything can conflict with it, so there is no accord or conflict.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §201)
     A reaction: This is a very interesting claim which goes beyond the private language question. It seems to imply, for example, Dancy's 'Particularism' about morality, which is a general rejection of rules and principles in moral thought.
One cannot obey a rule 'privately', because that is a practice, not the same as thinking one is obeying [Wittgenstein]
     Full Idea: 'Obeying a rule' is a practice. And to think one is obeying a rule is not to obey a rule. Hence it is not possible to obey a rule 'privately': otherwise thinking one was obeying a rule would be the same thing as obeying it.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §202)
     A reaction: The core of the Private Language argument. But if I drive on the right erroneously thinking it is the law, I can still make progress until I meet someone.
If individuals can't tell if they are following a rule, how does a community do it? [Grayling on Wittgenstein]
     Full Idea: The problem facing a putative private language-user - namely, that he cannot tell whether he is, or only thinks he is, following a rule - also faces the community as a whole; how does the community tell whether it is following a rule?
     From: comment on Ludwig Wittgenstein (Philosophical Investigations [1952], §580) by A.C. Grayling - Wittgenstein Ch.3
     A reaction: Nice question. If you really get into the sceptical frame of mind that Wittgenstein reached about rules, almost everything seems impossible. How can I move? How can I speak? How can one instant follow another? How can I understand a word?
18. Thought / C. Content / 6. Broad Content
Is white simple, or does it consist of the colours of the rainbow? [Wittgenstein]
     Full Idea: Is white simple, or does it consist of the colours of the rainbow?
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §047)
     A reaction: A nice challenge to externalism. White remains simple long after experts have told us it is complex.
Externalist accounts of mental content begin in Wittgenstein [Wittgenstein, by Heil]
     Full Idea: The roots of externalist accounts of mental content lie in Wittgenstein.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by John Heil - From an Ontological Point of View 18.2 n1
     A reaction: This points to the key idea being that content involves the whole language community, rather than that it involves the physical stuffs of the world, such as water. I suspect that Wittgenstein is right, but Putnam is wrong.
18. Thought / D. Concepts / 3. Ontology of Concepts / b. Concepts as abilities
Possessing a concept is knowing how to go on [Wittgenstein, by Peacocke]
     Full Idea: Wittgenstein implies that which concepts a thinker is capable of possessing depends on the ways in which he is capable of finding a natural way to go on.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Christopher Peacocke - A Study of Concepts 1.2
     A reaction: This doesn't seem to amount to much. Presumably someone who failed to grasp a concept would demonstrate the fact by going on in a silly way, and whether or not it was silly might not be obvious. A genius may go on in a quirky way.
Concepts direct our interests and investigations, and express those interests [Wittgenstein]
     Full Idea: Concepts lead us to make investigations; are the expression of our interest, and direct our interest.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §570)
     A reaction: This presumably points to the evolutionary origin of our concept-creating capacity, though I am not sure that it defines what a concept actually is.
Man learns the concept of the past by remembering [Wittgenstein]
     Full Idea: Man learns the concept of the past by remembering.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], II.13)
     A reaction: [quoted by Peacocke] Is it the case that we learn all of our concepts by doing? Obviously not, since we can be taught them. Could you have no long-term memories (head trauma), and be taught the concept of the past by someone else?
18. Thought / D. Concepts / 4. Structure of Concepts / h. Family resemblance
Various games have a 'family resemblance', as their similarities overlap and criss-cross [Wittgenstein]
     Full Idea: I shall say 'games' form a family, with a 'family resemblance', for the resemblances within a family - build, eyes, temperament etc. - overlap and criss-cross in the same way.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §067)
     A reaction: A very helpful idea for the nominalist view of universals, particularly for showing how concepts shade off indeterminately at the edges.
19. Language / A. Nature of Meaning / 1. Meaning
Wittgenstein rejected his earlier view that the form of language is the form of the world [Wittgenstein, by Morris,M]
     Full Idea: Wittgenstein's later work rejects the central thesis of the Tractatus's philosophy of language, that the form of language is the same as the form of the world.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Michael Morris - Guidebook to Wittgenstein's Tractatus Intro.4
     A reaction: I associate the earlier view with the stoic belief that nature is wholly rational, and that our reasoning can match it. I take it for granted that language largely matches the world, but we must explain why so many people believe absurdities.
19. Language / A. Nature of Meaning / 5. Meaning as Verification
Asking about verification is only one way of asking about the meaning of a proposition [Wittgenstein]
     Full Idea: Asking whether and how a proposition can be verified is only a particular way of asking 'How do you mean?' The answer is a contribution to the grammar of the proposition.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §353)
     A reaction: 'How' a proposition is verified seems utterly irrelevant. What situation in reality provides the verification must have something to do with the meaning. Cat-on-mat is what counts, not whether you see it, hear it or smell it.
19. Language / A. Nature of Meaning / 6. Meaning as Use
For Wittgenstein, words are defined by their use, just as chess pieces are [Wittgenstein, by Fogelin]
     Full Idea: For Wittgenstein, just as pieces in a game such as chess are defined by the rules that govern their moves, the meanings of words are similarly defined by the rules that govern their employment.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Robert Fogelin - Walking the Tightrope of Reason Ch.2
     A reaction: Fogelin's note points out that it is more complex than this. It is hard to dispute the chess case, but while words like 'and' and 'not' may be given entirely functional definitions, others don't work like that: John, run, red, solid, pain, ow! ….
We do not achieve meaning and understanding in our heads, but in the world [Wittgenstein, by Rowlands]
     Full Idea: For Wittgenstein, meaning and understanding are not things that we do or achieve in our heads; they are things we achieve in the world.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952], §202) by Mark Rowlands - Externalism Ch.5
     A reaction: Can't we achieve anything in our heads? Mental arithmetic seems to be fairly mental, unless we are going to be absurdly behaviouristic. If we can achieve some things in our heads, why not lots of things?
We all seem able to see quite clearly how sentences represent things when we use them [Wittgenstein]
     Full Idea: It it be asked, "How do sentences manage to represent?" the answer might be, "Don't you know? You certainly see it when you use them." For nothing is concealed.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §435)
     A reaction: A tool isn't its use, even though it becomes obvious how a tool works when it is used. It has a use because it has a certain nature or property.
In the majority of cases the meaning of a word is its use in the language [Wittgenstein]
     Full Idea: For a large class of cases - though not for all - the meaning of a word is its use in the language.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §043)
     A reaction: Defended by Paul Horwich, but I don't like this. If "swordfish" is a password, its meaning and its use are miles apart. Meaning connects to reality, but use doesn't.
19. Language / A. Nature of Meaning / 7. Meaning Holism / b. Language holism
To understand a sentence means to understand a language [Wittgenstein]
     Full Idea: To understand a sentence means to understand a language.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §198)
     A reaction: Does this make learning a language logically impossible? Helen Keller only knew one word at the beginning.
19. Language / A. Nature of Meaning / 10. Denial of Meanings
We don't have 'meanings' in our minds in addition to verbal expressions [Wittgenstein]
     Full Idea: When I think in language, there aren't 'meanings' going through my mind in addition to the verbal expressions.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §329)
     A reaction: No, but words have properties, like being meaningful, or long, or beautiful. They are not abstractions, or empty counters which can be used for anything.
Make the following experiment: say "It's cold here" and mean "It's warm here" [Wittgenstein]
     Full Idea: Make the following experiment: say "It's cold here" and mean "It's warm here".
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §510)
     A reaction: A lovely experiment, whatever it proves. It is easier if the meaning is the truth, rather than the words. I try to weld a new word onto my experience.
19. Language / B. Reference / 1. Reference theories
How do words refer to sensations? [Wittgenstein]
     Full Idea: How do words refer to sensations?
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §244)
     A reaction: A very nice question, to be remembered when discussing how we refer to beauty, gold, water or the present King of France.
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
The standard metre in Paris is neither one metre long nor not one metre long [Wittgenstein]
     Full Idea: There is one thing of which one can say neither that it is one metre long, nor that it is not one metre long, and that is the standard metre in Paris.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §050)
     A reaction: The remark which inspired Kripke's causal theory. Clearly W. is wrong, because it is one metre long, but why is it that length?
19. Language / F. Communication / 4. Private Language
Was Wittgenstein's problem between individual and community, or between occasions for an individual? [Rowlands on Wittgenstein]
     Full Idea: There are two interpretations of Wittgenstein here: the community interpretation sees error in a rule between the individual and the community, where the individual interpretation sees the problem between repeated occasions in the use of a sign.
     From: comment on Ludwig Wittgenstein (Philosophical Investigations [1952], §202) by Mark Rowlands - Externalism Ch.5
     A reaction: Rowlands brings out how a lot hangs on which of these two interpretations we opt for, but also that if the individual has a problem, this may logically imply the same problem for the community. The individual interpretation would be a deeper problem.
If a brilliant child invented a name for a private sensation, it couldn't communicate it [Wittgenstein]
     Full Idea: Let's assume the child is a genius and itself invents a name for the sensation! - But then, of course, he couldn't make himself understood when he used the word.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §257)
     A reaction: [His example is a sensation with no behaviour] Sensations are not just related to behaviour; they are related to external objects, and to parts of the body. We doubt the sensations of others if they can't name the object or the body part.
We cannot doublecheck mental images for correctness (or confirm news with many copies of the paper) [Wittgenstein]
     Full Idea: If the mental image of a train timetable cannot itself be tested for correctness, how can it confirm the correctness of the first memory? (As if someone were to buy several copies of the morning paper to assure himself that what it said was true).
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §265)
     A reaction: An important point for the epistemological sceptic. Could God do an infinite regress of checks on the truth of his mental images?
If we only named pain by our own case, it would be like naming beetles by looking in a private box [Wittgenstein]
     Full Idea: If someone says he only knows what pain is from his own case, suppose everyone had a box with something in it (a 'beetle'). We can't see into other boxes, so we say what a beetle is by looking in our own box. The contents of each box could be different.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §293)
     A reaction: But pain is private. Children must guess the meaning of parts of the language that refer to inner experience, like 'sad' or 'hopeful'. Body language brings our private concepts together, but error seems possible.
If the reference is private, that is incompatible with the sense being public [Wittgenstein, by Scruton]
     Full Idea: Wittgenstein's claim is that the assumption that the reference is private (being observable to one person alone) is incompatible with the hypothesis that the sense is public.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952], §293) by Roger Scruton - Short History of Modern Philosophy Ch.19
     A reaction: An illuminating summary, showing the link between the private language argument and modern 'externalism' about the meaning of concepts (e.g. Idea 4099). I still don't find Wittgenstein's claim conclusive. Something is definitely private.
Getting from perceptions to words cannot be a private matter; the rules need an institution of use [Wittgenstein]
     Full Idea: I could not apply any rules to a private transition from what is seen to words. Here the rules really would hang in the air; for the institution of their use is lacking.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §380)
     A reaction: That puts the argument nicely. In studying art or wine you learn what to say about your private experiences.
To imagine a language means to imagine a form of life [Wittgenstein]
     Full Idea: To imagine a language means to imagine a form of life.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §019)
     A reaction: I take this to be about the transparency of language, but it supports meaning as truth conditions, rather than as use.
19. Language / F. Communication / 6. Interpreting Language / c. Principle of charity
Common human behaviour enables us to interpret an unknown language [Wittgenstein]
     Full Idea: The common behaviour of mankind is the system of reference by means of which we interpret an unknown language.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §206)
     A reaction: This is a behaviourist spin on the idea of charity, but it leads to Davidson's assumption that most alien beliefs must be true.
To communicate, language needs agreement in judgment as well as definition [Wittgenstein]
     Full Idea: If language is to be a means of communication there must be agreement not only in definitions but also (queer as this may sound) in judgments.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §242)
     A reaction: If someone is locked into a highly alien viewpoint, then communication with them does seem to be virtually impossible. Amenability to reason, and consensus on elementary facts, seems to be the sine qua non of communication.
20. Action / A. Definition of Action / 3. Actions and Events
What is left over if I subtract my arm going up from my raising my arm? [Wittgenstein]
     Full Idea: What is left over if I subtract the fact that my arm goes up from the fact that I raise my arm?
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §621)
     A reaction: Wittgenstein's implication seems to be that nothing is left over, but I would have thought that the will was the thing left over when you decide to raise your arm, but then discover that you are paralysed.
29. Religion / D. Religious Issues / 1. Religious Commitment / b. Religious Meaning
Grammar tells what kind of object anything is - and theology is a kind of grammar [Wittgenstein]
     Full Idea: Grammar tells what kind of object anything is. (Theology as grammar)
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], §373)
     A reaction: A classic twentieth century blunder, originating in Frege and culminating in Quine, of thinking that the analysis of language is the last word in ontology.
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
The human body is the best picture of the human soul [Wittgenstein]
     Full Idea: The human body is the best picture of the human soul.
     From: Ludwig Wittgenstein (Philosophical Investigations [1952], II.iv)
     A reaction: Nice. How did we imagine the soul before reading that remark? My soul requires fingernails and eyelids in order to fulfil its essential nature.