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All the ideas for 'Lectures 1930-32 (student notes)', 'Cantorian Abstraction: Recon. and Defence' and 'The Guide of the Perplexed'

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42 ideas

1. Philosophy / C. History of Philosophy / 1. History of Philosophy
The history of philosophy only matters if the subject is a choice between rival theories [Wittgenstein]
     Full Idea: If philosophy were a matter of choice between rival theories, then it would be sound to teach it historically. But if it is not, then it is a fault to teach it historically, because it is quite unnecessary; we can tackle the subject direct.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C V A)
     A reaction: Wittgenstein was a bit notorious for not knowing the history of the subject terribly well, and this explains why. Presumably our tackling the subject direct will not have the dreadful consequence of producing yet another theory.
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / d. Philosophy as puzzles
Philosophy tries to be rid of certain intellectual puzzles, irrelevant to daily life [Wittgenstein]
     Full Idea: Philosophy is the attempt to be rid of a particular kind of puzzlement. This 'philosophical' puzzlement is one of the intellect and not of instinct. Philosophical puzzles are irrelevant to our every-day life.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A I.1)
     A reaction: All enquiry begins with puzzles, and they are cured by explanations, which result in understanding. In that sense he is right. I entirely disagree that the puzzles are irrelevant to daily life.
1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
Philosophers express puzzlement, but don't clearly state the puzzle [Wittgenstein]
     Full Idea: Philosophers as 'Why?' and 'What?' without knowing clearly what their questions are. They are expressing a feeling of mental uneasiness.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B I.1)
     A reaction: He suggests it is childish to express puzzlement, instead of asking for precise information. How odd. All enquiries start with vague puzzlement, which gradually comes into focus, or else is abandoned.
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
We don't need a theory of truth, because we use the word perfectly well [Wittgenstein]
     Full Idea: It is nonsense to try to find a theory of truth, because we can see that in everyday life we use the word quite clearly and definitely in various different senses.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C V B)
     A reaction: This was a year before Tarski published his famous theory of truth for formal languages. Prior to that, most philosophers were giving up on truth. Would he say the same about 'gravity' or 'inflation'?
1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
We already know what we want to know, and analysis gives us no new facts [Wittgenstein]
     Full Idea: In philosophy we know already all that we want to know; philosophical analysis does not give us any new facts.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B V.1)
2. Reason / F. Fallacies / 8. Category Mistake / a. Category mistakes
Words of the same kind can be substituted in a proposition without producing nonsense [Wittgenstein]
     Full Idea: 'Blue' and 'brown' are of the same kind, for the substitution of one for the other, though it may falsify the proposition, does not make nonsense of it.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A I.4)
     A reaction: He chooses an easy example, because they are determinates of the determinable 'coloured'. What if I say 'the sky is blue', and then substitute 'frightening' for 'blue'?
2. Reason / F. Fallacies / 8. Category Mistake / b. Category mistake as syntactic
Talking nonsense is not following the rules [Wittgenstein]
     Full Idea: Talking nonsense is not following the rules.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C X)
     A reaction: He doesn't seem to distinguish between syntax and semantics, and makes it sound as if all nonsense is syntactic, which it isn't.
Grammar says that saying 'sound is red' is not false, but nonsense [Wittgenstein]
     Full Idea: If grammar says that you cannot say that a sound is red, it means not that it is false to say so but that it is nonsense - i.e. not a language at all.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B IX.6)
     A reaction: I am baffled as to why he thinks 'grammar' is what prohibits such a statement. Surely the world, the nature of sound and colour, is what makes the application of the predicate wrong. Sounds aren't coloured, so they can't be red. False, not nonsense.
3. Truth / A. Truth Problems / 2. Defining Truth
There is no theory of truth, because it isn't a concept [Wittgenstein]
     Full Idea: It is wrong to say that there is any one theory of truth, for truth is not a concept.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C V B)
     A reaction: This makes you wonder how he understood the word 'concept'. In most modern discussions truth seems to be a concept, and in Frege it can be an unsaturated predicate which is satisfied by sentences or thoughts.
3. Truth / C. Correspondence Truth / 1. Correspondence Truth
All thought has the logical form of reality [Wittgenstein]
     Full Idea: Thought must have the logical form of reality if it is to be thought at all.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A V.1)
     A reaction: This links nicely the idea that true thoughts somehow share the structure of what they refer to, with the idea of logical form in logic. But maybe logical form is a fiction we offer in order to obtain a spurious map of reality.
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
In logic nothing is hidden [Wittgenstein]
     Full Idea: In logic nothing is hidden.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B XII.3)
     A reaction: If so, then the essence of logic must be there for all to see. The rules of natural deduction are a good shot at showing this.
5. Theory of Logic / C. Ontology of Logic / 4. Logic by Convention
Laws of logic are like laws of chess - if you change them, it's just a different game [Wittgenstein]
     Full Idea: I might as well question the laws of logic as the laws of chess. If I change the rules it is a different game and there is an end of it.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A XI.3)
     A reaction: No, that isn't the end of it, because there are meta-criteria for preferring one game to another. Why don't we just give up classical logic? It would be such fun to have a wild wacky logic. We can start with 'tonk'.
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
Contradiction is between two rules, not between rule and reality [Wittgenstein]
     Full Idea: Contradiction is between one rule and another, not between rule and reality.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C XIII)
     A reaction: If I say 'he is sitting' and 'he is standing', it seems to be reality which produces the contradiction. What 'rule' could possibly do it? The rule which says sitting and standing are incompatible? But what makes that so?
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / c. not
We may correctly use 'not' without making the rule explicit [Wittgenstein]
     Full Idea: Correct use does not imply the ability to make the rules explicit. Understanding 'not' is like understanding a move in chess.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B XII.1)
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / d. and
Saying 'and' has meaning is just saying it works in a sentence [Wittgenstein]
     Full Idea: When we say that the word 'and' has meaning what we mean is that it works in a sentence and is not just a flourish.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B VIII.2)
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
I think of variables as objects rather than as signs [Fine,K]
     Full Idea: It is natural nowadays to think of variables as a certain kind of sign, but I wish to think of them as a certain kind of object.
     From: Kit Fine (Cantorian Abstraction: Recon. and Defence [1998], §2)
     A reaction: Fine has a theory based on 'arbitrary objects', which is a rather charming idea. The cell of a spreadsheet is a kind of object, I suppose. A variable might be analogous to a point in space, where objects can locate themselves.
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
A person's name doesn't mean their body; bodies don't sit down, and their existence can be denied [Wittgenstein]
     Full Idea: The meaning of the words 'Professor Moore' is not a certain human body, because we do not say that the meaning sits on the sofa, and the words occur in the proposition 'Professor Moore does not exist'.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B Easter)
     A reaction: Brilliant. Love it. Kripke ending up denying the existence of 'meanings'.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
We don't get 'nearer' to something by adding decimals to 1.1412... (root-2) [Wittgenstein]
     Full Idea: We say we get nearer to root-2 by adding further figures after the decimal point: 1.1412.... This suggests there is something we can get nearer to, but the analogy is a false one.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], Notes)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Infinity is not a number, so doesn't say how many; it is the property of a law [Wittgenstein]
     Full Idea: 'Infinite' is not an answer to the question 'How many?', since the infinite is not a number. ...Infinity is the property of a law, not of an extension.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A VII.2)
7. Existence / D. Theories of Reality / 8. Facts / b. Types of fact
There are no positive or negative facts; these are just the forms of propositions [Wittgenstein]
     Full Idea: There are no positive or negative facts. 'Positive' and 'negative' refer to the form of propositions, and not to the facts which verify or falsify them.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C XIII)
     A reaction: Personally I think if we are going to allow the world to be full of 'facts', then there are negative, conjunctive, disjunctive and hypothetical facts.
8. Modes of Existence / D. Universals / 5. Universals as Concepts
Using 'green' is a commitment to future usage of 'green' [Wittgenstein]
     Full Idea: If I say this is green, I must say that other things are green too. I am committed to a future usage.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B VI.2)
     A reaction: This seems to suggest that the eternal verity of a universal concept is just a convention of stability in a language.
10. Modality / C. Sources of Modality / 3. Necessity by Convention
For each necessity in the world there is an arbitrary rule of language [Wittgenstein]
     Full Idea: To a necessity in the world there corresponds an arbitrary rule in language.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B XIV.2)
     A reaction: This seems to be hardcore logical positivism, making all necessities arbitrary. Compare Quine on the number of planets.
11. Knowledge Aims / A. Knowledge / 2. Understanding
Understanding is translation, into action or into other symbols [Wittgenstein]
     Full Idea: Understanding is really translation, whether into other symbols or into action.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B I.5)
     A reaction: The second part of this sounds like pure pragmatism. To do is to understand? I doubt it. Do animals understand anything?
12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory
We live in sense-data, but talk about physical objects [Wittgenstein]
     Full Idea: The world we live in is the world of sense-data, but the world we talk about is the world of physical objects.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], p.82), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 13 'Verif'
     A reaction: I really like that one. Even animals, I surmise, think of objects quite differently from the way they immediately experience them.
12. Knowledge Sources / B. Perception / 4. Sense Data / d. Sense-data problems
Part of what we mean by stating the facts is the way we tend to experience them [Wittgenstein]
     Full Idea: There is no need of a theory to reconcile what we know about sense data and what we believe about physical objects, because part of what we mean by saying that a penny is round is that we see it as elliptical in such and such conditions.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C III)
     A reaction: This is an interesting and cunning move to bridge the gap between our representations and reallity. We may surmise how a thing really is, but then be surprised by the sense-data we get from it.
12. Knowledge Sources / E. Direct Knowledge / 4. Memory
If you remember wrongly, then there must be some other criterion than your remembering [Wittgenstein]
     Full Idea: If you remember wrongly, then there must be some other criterion than your remembering. If you admit another test, then your memory itself is not the test.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C VII)
     A reaction: If I fear that I am remembering some private solitary event wrongly, there is no other criterion to turn to, so I'm stuck. Sometimes dubious memories are all we have.
14. Science / D. Explanation / 1. Explanation / b. Aims of explanation
Explanation and understanding are the same [Wittgenstein]
     Full Idea: For us explanation and understanding are the same, understanding being the correlate of explanation.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B XI.2)
     A reaction: I'm not convinced that they are 'the same', but they are almost interdependent ideas. Strevens has a nice paper on this.
Explanation gives understanding by revealing the full multiplicity of the thing [Wittgenstein]
     Full Idea: An explanation gives understanding, ...but it cannot teach you understanding, it cannot create understanding. It makes further distinctions i.e. it increases multiplicity. When multiplicity is complete, then there is no further misunderstanding.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B X.3)
     A reaction: The thought seems to resemble Aristotle's idea of definition as gradual division of the subject. To understand is the dismantle the parts and lay them out before us. Wittgenstein was very interested in explanation at this time.
14. Science / D. Explanation / 2. Types of Explanation / i. Explanations by mechanism
A machine strikes us as being a rule of movement [Wittgenstein]
     Full Idea: We are accustomed to look on a machine as the expression of a rule of movement.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B VII.2)
     A reaction: What a beautiful definition of a machine! I like this because it connects the two halves of my view of the 'essence' of a thing, as derived from Aristotle, as both a causal mechanism and an underlying principle. Cf Turing machines.
14. Science / D. Explanation / 3. Best Explanation / a. Best explanation
If an explanation is good, the symbol is used properly in the future [Wittgenstein]
     Full Idea: The criterion of an explanation is whether the symbol explained is used properly in the future.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B II.4)
     A reaction: This appears to be a pragmatic criterion for the best explanation. It presumably rests on his doctrine that meaning is use, so good explanation is understanding meanings.
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
If green is abstracted from a thing, it is only seen as a type if it is common to many things [Fine,K]
     Full Idea: In traditional abstraction, the colour green merely has the intrinsic property of being green, other properties of things being abstracted away. But why should that be regarded as a type? It must be because the property is common to the instances.
     From: Kit Fine (Cantorian Abstraction: Recon. and Defence [1998], §5)
     A reaction: A nice question which shows that the much-derided single act of abstraction is not sufficient to arrive at a concept, so that abstraction is a more complex matter (perhaps even a rational one) than simple empiricists believe.
18. Thought / A. Modes of Thought / 1. Thought
Thought is an activity which we perform by the expression of it [Wittgenstein]
     Full Idea: Thought is an activity which we perform by the expression of it, and lasts as long as the expression.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B VIII)
     A reaction: I take this to be an outmoded view of thought, which modern cognitive science has undermined, by showing how little of our thinking is actually conscious.
18. Thought / E. Abstraction / 2. Abstracta by Selection
To obtain the number 2 by abstraction, we only want to abstract the distinctness of a pair of objects [Fine,K]
     Full Idea: In abstracting from the elements of a doubleton to obtain 2, we do not wish to abstract away from all features of the objects. We wish to take account of the fact that the two objects are distinct; this alone should be preserved under abstraction.
     From: Kit Fine (Cantorian Abstraction: Recon. and Defence [1998], §3)
     A reaction: This is Fine's strategy for meeting Frege's objection to abstraction, summarised in Idea 9146. It seems to use the common sense idea that abstraction is not all-or-nothing. Abstraction has degrees (and levels).
We should define abstraction in general, with number abstraction taken as a special case [Fine,K]
     Full Idea: Number abstraction can be taken to be a special case of abstraction in general, which can then be defined without recourse to the concept of number.
     From: Kit Fine (Cantorian Abstraction: Recon. and Defence [1998], §3)
     A reaction: At last, a mathematical logician recognising that they don't have a monopoly on abstraction. It is perfectly obvious that abstractions of simple daily concepts must be chronologically and logically prior to number abstraction. Number of what?
18. Thought / E. Abstraction / 8. Abstractionism Critique
After abstraction all numbers seem identical, so only 0 and 1 will exist! [Fine,K]
     Full Idea: In Cantor's abstractionist account there can only be two numbers, 0 and 1. For abs(Socrates) = abs(Plato), since their numbers are the same. So the number of {Socrates,Plato} is {abs(Soc),abs(Plato)}, which is the same number as {Socrates}!
     From: Kit Fine (Cantorian Abstraction: Recon. and Defence [1998], §1)
     A reaction: Fine tries to answer this objection, which arises from §45 of Frege's Grundlagen. Fine summarises that "indistinguishability without identity appears to be impossible". Maybe we should drop talk of numbers in terms of sets.
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
A proposition draws a line around the facts which agree with it [Wittgenstein]
     Full Idea: A proposition gives reality a degree of freedom; it draws a line round the facts which agree with it, and distinguishes them from those which do not.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B XIII.2)
     A reaction: This seems to be the idea of meaning as the range of truth conditions. Propositions as sets of possible worlds extends this into possible facts which agree with the proposition. Most facts neither agree nor disagree with some proposition.
19. Language / A. Nature of Meaning / 5. Meaning as Verification
The meaning of a proposition is the mode of its verification [Wittgenstein]
     Full Idea: The meaning of a proposition is the mode of its verification (and two propositions cannot have the same verification).
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C I)
     A reaction: Does this mean that if two sentences have the same mode of verification, then they must be expressing the same proposition? I guess so.
19. Language / A. Nature of Meaning / 7. Meaning Holism / a. Sentence meaning
Words function only in propositions, like levers in a machine [Wittgenstein]
     Full Idea: Words function only in propositions, like the levers in a machine.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A I.4)
     A reaction: Hm. Consider the word 'tree'. Did you manage to do it? Was it just a noise?
19. Language / D. Propositions / 1. Propositions
A proposition is any expression which can be significantly negated [Wittgenstein]
     Full Idea: Any affirmation can be negated: if it has sense to say p it also has sense to say ¬p. ...A proposition therefore is any expression which can be significantly negated.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B I.2)
     A reaction: I'm not sure about 'therefore'. I'm thinking you would have to already grasp the proposition in order to apply his negation test.
26. Natural Theory / D. Laws of Nature / 11. Against Laws of Nature
Laws of nature are an aspect of the phenomena, and are just our mode of description [Wittgenstein]
     Full Idea: The laws of nature are not outside phenomena. They are part of language and of our way of describing things; you cannot discuss them apart from their physical manifestation.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C V C)
     A reaction: I suppose this amounts to a Humean regularity theory - that the descriptions pick out patterns in the manifestations. I like the initial claim that they are not external to phenomena.
28. God / A. Divine Nature / 2. Divine Nature
We can approach knowledge of God by negative attributes [Maimonides]
     Full Idea: You will come nearer to the knowledge and comprehension of God by the negative attributes.
     From: Moses Maimonides (The Guide of the Perplexed [1190], p.86), quoted by Brian Davies - Introduction to the Philosophy of Religion 2 'Negation'
     A reaction: Illustrated by grasping what a ship is by eliminating other categories it might belong to. The assumption is that you have a known and finite list - something like Aristotle's categories. Maimonides fears we know too little for positive attributes.
28. God / C. Attitudes to God / 4. God Reflects Humanity
Thinking of God as resembling humans results from a bad translation of Genesis 1:26 [Maimonides]
     Full Idea: Mistranslation of 'image' has been the cause of a crass anthropomorphism because of the verse 'Let us make man in Our image after Our likeness' (Gen.1:26). They think God has the shape and outline of man, ..with face and hands like themselves.
     From: Moses Maimonides (The Guide of the Perplexed [1190], I.1)
     A reaction: It's interesting that Michelangelo still visualises God as an old man. The idea won't go away, presumably because God is understood as a 'person', in Locke's sense, though of a very special kind.