Ideas of Ludwig Wittgenstein, by Theme

[Austrian, 1889 - 1951, Born Vienna. Aeronautics at Manchester, then philosophy with Russell in Cambridge. Austrian army in WWI. Teacher in the Alps, then back to Cambridge. Died in Cambridge.]

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1. Philosophy / A. Wisdom / 2. Wise People
7536 If you hope to improve the world, all you can do is improve yourself
16010 While faith is a passion (as Kierkegaard says), wisdom is passionless
1. Philosophy / C. History of Philosophy / 1. History of Philosophy
18730 The history of philosophy only matters if the subject is a choice between rival theories
1. Philosophy / D. Nature of Philosophy / 1. Philosophy
2937 What we cannot speak about we must pass over in silence
2626 A philosopher is outside any community of ideas
1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
7085 The main problem of philosophy is what can and cannot be thought and expressed [Grayling]
6870 I say (contrary to Wittgenstein) that philosophy expresses what we thought we must be silent about [Ansell Pearson]
2512 Philosophy is a battle against the bewitchment of our intelligence by means of language
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / d. Philosophy as puzzles
18704 Philosophy tries to be rid of certain intellectual puzzles, irrelevant to daily life
1. Philosophy / D. Nature of Philosophy / 6. Hopes for Philosophy
2944 If a question can be framed at all, it is also possible to answer it
1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
9810 The 'Tractatus' is a masterpiece of anti-philosophy [Badiou]
23459 This work solves all the main problems, but that has little value
23512 Once you understand my book you will see that it is nonsensical
18710 Philosophers express puzzlement, but don't clearly state the puzzle
4148 What is your aim in philosophy? - To show the fly the way out of the fly-bottle
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
18274 Analysis complicates a statement, but only as far as the complexity of its meaning
6429 All complex statements can be resolved into constituents and descriptions
23492 Our language is an aspect of biology, and so its inner logic is opaque
23510 Most philosophical questions arise from failing to understand the logic of language
2938 The limits of my language means the limits of my world
18732 We don't need a theory of truth, because we use the word perfectly well
22490 Bring words back from metaphysics to everyday use
1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
23499 This book says we should either say it clearly, or shut up
18714 We already know what we want to know, and analysis gives us no new facts
1. Philosophy / G. Scientific Philosophy / 3. Scientism
23508 Science is all the true propositions
2. Reason / B. Laws of Thought / 3. Non-Contradiction
6566 The problem is to explain the role of contradiction in social life
2. Reason / B. Laws of Thought / 6. Ockham's Razor
2939 If a sign is useless it is meaningless; that is the point of Ockham's maxim
2. Reason / F. Fallacies / 8. Category Mistake / a. Category mistakes
18706 Words of the same kind can be substituted in a proposition without producing nonsense
2. Reason / F. Fallacies / 8. Category Mistake / b. Category mistake as syntactic
18719 Grammar says that saying 'sound is red' is not false, but nonsense
18735 Talking nonsense is not following the rules
3. Truth / A. Truth Problems / 2. Defining Truth
18731 There is no theory of truth, because it isn't a concept
3. Truth / B. Truthmakers / 2. Truthmaker Relation
10910 The best account of truth-making is isomorphism [Mulligan/Simons/Smith]
3. Truth / B. Truthmakers / 5. What Makes Truths / c. States of affairs make truths
23462 He says the world is the facts because it is the facts which fix all the truths [Morris,M]
3. Truth / B. Truthmakers / 11. Truthmaking and Correspondence
18349 All truths have truth-makers, but only atomic truths correspond to them [Rami]
3. Truth / C. Correspondence Truth / 1. Correspondence Truth
10967 Wittgenstein's picture theory is the best version of the correspondence theory of truth [Read]
7087 Language is [propositions-elementary propositions-names]; reality is [facts-states of affairs-objects] [Grayling]
4702 The account of truth in the 'Tractatus' seems a perfect example of the correspondence theory [O'Grady]
7056 Pictures reach out to or feel reality, touching at the edges, correlating in its parts
18707 All thought has the logical form of reality
3. Truth / C. Correspondence Truth / 2. Correspondence to Facts
23483 Proposition elements correlate with objects, but the whole picture does not correspond to a fact [Morris,M]
3. Truth / H. Deflationary Truth / 1. Redundant Truth
11074 'It is true that this follows' means simply: this follows
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
16908 We can dispense with self-evidence, if language itself prevents logical mistakes [Jeshion]
23502 Logic fills the world, to its limits
23504 Logic concerns everything that is subject to law; the rest is accident
18724 In logic nothing is hidden
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
6428 Wittgenstein is right that logic is just tautologies [Russell]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
11062 Logic is a priori because it is impossible to think illogically
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
18277 If q implies p, that is justified by q and p, not by some 'laws' of inference
5. Theory of Logic / C. Ontology of Logic / 1. Ontology of Logic
18162 The propositions of logic are analytic tautologies
5. Theory of Logic / C. Ontology of Logic / 2. Platonism in Logic
7537 Wittgenstein convinced Russell that logic is tautologies, not Platonic forms [Monk]
5. Theory of Logic / C. Ontology of Logic / 4. Logic by Convention
18709 Laws of logic are like laws of chess - if you change them, it's just a different game
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
23496 Two colours in the same place is ruled out by the logical structure of colour
18736 Contradiction is between two rules, not between rule and reality
5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
18154 The sign of identity is not allowed in 'Tractatus' [Bostock]
13429 The identity sign is not essential in logical notation, if every sign has a different meaning [Ramsey]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
18276 A statement's logical form derives entirely from its constituents
18268 Apparent logical form may not be real logical form
18743 Wittgenstein says we want the grammar of problems, not their first-order logical structure [Horsten/Pettigrew]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
6563 'And' and 'not' are non-referring terms, which do not represent anything [Fogelin]
10905 My fundamental idea is that the 'logical constants' do not represent
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / c. not
23493 'Not' isn't an object, because not-not-p would then differ from p
18723 We may correctly use 'not' without making the rule explicit
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / d. and
18718 Saying 'and' has meaning is just saying it works in a sentence
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
7784 'Object' is a pseudo-concept, properly indicated in logic by the variable x
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
23506 Names are primitive, and cannot be analysed
18727 A person's name doesn't mean their body; bodies don't sit down, and their existence can be denied
4139 Naming is a preparation for description
5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive
4946 A name is not determined by a description, but by a cluster or family [Kripke]
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
7089 A name is primitive, and its meaning is the object
5. Theory of Logic / G. Quantification / 1. Quantification
9467 Wittgenstein tried unsuccessfully to reduce quantifiers to conjunctions and disjunctions [Jacquette]
5. Theory of Logic / H. Proof Systems / 1. Proof Systems
15089 Logical proof just explicates complicated tautologies
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
13830 Logical truths are just 'by-products' of the introduction rules for logical constants [Hacking]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
19292 Logic doesn't split into primitive and derived propositions; they all have the same status
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
6569 'This sentence is false' sends us in a looping search for its proposition [Fogelin]
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
18281 In mathematics everything is algorithm and nothing is meaning
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
18738 We don't get 'nearer' to something by adding decimals to 1.1412... (root-2)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
18708 Infinity is not a number, so doesn't say how many; it is the property of a law
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / a. Defining numbers
18160 The concept of number is just what all numbers have in common
18153 A number is a repeated operation
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / b. Mathematics is not set theory
18161 The theory of classes is superfluous in mathematics
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
11073 Two and one making three has the necessity of logical inference
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
6849 Wittgenstein hated logicism, and described it as a cancerous growth [Monk]
23509 The logic of the world is shown by tautologies in logic, and by equations in mathematics
7. Existence / A. Nature of Existence / 1. Nature of Existence
13133 The world is facts, not things. Facts determine the world, and the world divides into facts
7. Existence / C. Structure of Existence / 6. Fundamentals / d. Logical atoms
23472 The sense of propositions relies on the world's basic logical structure
23463 Atomic facts correspond to true elementary propositions
7090 The 'Tractatus' is an extreme example of 'Logical Atomism' [Grayling]
23464 In atomic facts the objects hang together like chain links
23471 The structure of an atomic fact is how its objects combine; this possibility is its form
21682 If a proposition is elementary, no other elementary proposition contradicts it
22319 Analysis must end in elementary propositions, which are combinations of names
21683 Nothing can be inferred from an elementary proposition
7. Existence / D. Theories of Reality / 7. Facts / a. Facts
23473 Do his existent facts constitute the world, or determine the world? [Morris,M]
7. Existence / D. Theories of Reality / 7. Facts / b. Types of fact
18737 There are no positive or negative facts; these are just the forms of propositions
7. Existence / D. Theories of Reality / 7. Facts / d. Negative facts
22312 Facts can be both positive and negative [Potter]
22311 The world is determined by the facts, and there are no further facts
22313 The existence of atomic facts is a positive fact, their non-existence a negative fact
22314 On white paper a black spot is a positive fact and a white spot a negative fact
8. Modes of Existence / A. Relations / 2. Internal Relations
7969 The order of numbers is an internal relation, not an external one
7968 A relation is internal if it is unthinkable that its object should not possess it
8. Modes of Existence / D. Universals / 5. Universals as Concepts
18715 Using 'green' is a commitment to future usage of 'green'
9. Objects / A. Existence of Objects / 1. Physical Objects
23466 Objects are the substance of the world
9. Objects / A. Existence of Objects / 3. Objects in Thought
22320 An 'object' is just what can be referred to without possible non-existence
9. Objects / A. Existence of Objects / 5. Simples
23467 Objects are simple
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
23468 Apart from the facts, there is only substance
9. Objects / B. Unity of Objects / 2. Substance / b. Need for substance
10710 We accept substance, to avoid infinite backwards chains of meaning [Potter]
9. Objects / D. Essence of Objects / 5. Essence as Kind
15106 Essence is expressed by grammar
9. Objects / D. Essence of Objects / 9. Essence and Properties
22321 To know an object we must know the form and content of its internal properties [Potter]
9. Objects / F. Identity among Objects / 1. Concept of Identity
6056 Identity is not a relation between objects
9. Objects / F. Identity among Objects / 2. Defining Identity
22322 You can't define identity by same predicates, because two objects with same predicates is assertable
9. Objects / F. Identity among Objects / 5. Self-Identity
6057 Two things can't be identical, and self-identity is an empty concept
10. Modality / A. Necessity / 3. Types of Necessity
9442 The only necessity is logical necessity
10. Modality / C. Sources of Modality / 3. Necessity by Convention
18726 For each necessity in the world there is an arbitrary rule of language
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
23495 The tautologies of logic show the logic of language and the world
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
23487 What is thinkable is possible
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
23470 Each thing is in a space of possible facts
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
23507 Unlike the modern view of a set of worlds, Wittgenstein thinks of a structured manifold of them [White,RM]
23469 An imagined world must have something in common with the real world
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
11027 To know an object you must know all its possible occurrences
23465 The 'form' of an object is its possible roles in facts
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
12869 Two objects may only differ in being different
11. Knowledge Aims / A. Knowledge / 2. Understanding
18712 Understanding is translation, into action or into other symbols
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
6600 The belief that fire burns is like the fear that it burns
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
4153 Are sense-data the material of which the universe is made?
11. Knowledge Aims / C. Knowing Reality / 4. Solipsism
23503 Strict solipsism is pure realism, with the self as a mere point in surrounding reality
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
16907 If the truth doesn't follow from self-evidence, then self-evidence cannot justify a truth
12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
23500 My main problem is the order of the world, and whether it is knowable a priori
23479 The Tractatus aims to reveal the necessities, without appealing to synthetic a priori truths [Morris,M]
23501 There is no a priori order of things
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
7088 Logic and maths can't say anything about the world, since, as tautologies, they are consistent with all realities [Grayling]
12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective
16909 Logic is a priori because we cannot think illogically
12. Knowledge Sources / A. A Priori Knowledge / 11. Denying the A Priori
23485 No pictures are true a priori
12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory
18280 We live in sense-data, but talk about physical objects
12. Knowledge Sources / B. Perception / 4. Sense Data / d. Sense-data problems
18729 Part of what we mean by stating the facts is the way we tend to experience them
6501 As sense-data are necessarily private, they are attacked by Wittgenstein's objections [Robinson,H]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
11079 How do I decide when to accept or obey an intuition?
12. Knowledge Sources / E. Direct Knowledge / 4. Memory
18734 If you remember wrongly, then there must be some other criterion than your remembering
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
3597 Foundations need not precede other beliefs
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
3790 Causes of beliefs are irrelevant to their contents
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
6591 Doubts can't exist if they are inexpressible or unanswerable
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
3596 Total doubt can't even get started [Williams,M]
4160 One can mistrust one's own senses, but not one's own beliefs
14. Science / B. Scientific Theories / 3. Instrumentalism
17665 The 'Tractatus' is instrumentalist about laws of nature [Armstrong]
14. Science / C. Induction / 2. Aims of Induction
2941 Induction accepts the simplest law that fits our experiences
14. Science / D. Explanation / 1. Explanation / b. Aims of explanation
18721 Explanation and understanding are the same
18720 Explanation gives understanding by revealing the full multiplicity of the thing
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
17673 The modern worldview is based on the illusion that laws explain nature
14. Science / D. Explanation / 2. Types of Explanation / i. Explanations by mechanism
18716 A machine strikes us as being a rule of movement
14. Science / D. Explanation / 3. Best Explanation / a. Best explanation
18713 If an explanation is good, the symbol is used properly in the future
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds
19273 I don't have the opinion that people have minds; I just treat them as such
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / d. Other minds by analogy
5663 It is irresponsible to generalise from my own case of pain to other people's
19272 To imagine another's pain by my own, I must imagine a pain I don't feel, by one I do feel
15. Nature of Minds / B. Features of Minds / 3. Privacy
4161 If a lion could talk, we could not understand him
7392 If a lion could talk, it would be nothing like other lions [Dennett]
16. Persons / B. Nature of the Self / 4. Presupposition of Self
22323 The philosophical I is the metaphysical subject, the limit - not a part of the world
2940 The subject stands outside our understanding of the world
16. Persons / C. Self-Awareness / 1. Introspection
5676 To say that I 'know' I am in pain means nothing more than that I AM in pain
16. Persons / D. Continuity of the Self / 3. Reference of 'I'
22419 'I' is a subject in 'I am in pain' and an object in 'I am bleeding' [McGinn]
16. Persons / E. Rejecting the Self / 4. Denial of the Self
23498 The modern idea of the subjective soul is composite, and impossible
17. Mind and Body / D. Property Dualism / 6. Mysterianism
4154 Why are we not aware of the huge gap between mind and brain in ordinary life?
18. Thought / A. Modes of Thought / 1. Thought
18717 Thought is an activity which we perform by the expression of it
18. Thought / A. Modes of Thought / 6. Judgement / b. Error
23475 The form of a proposition must show why nonsense is unjudgeable
18. Thought / A. Modes of Thought / 10. Rule Following
4158 An 'inner process' stands in need of outward criteria
6165 Every course of action can either accord or conflict with a rule, so there is no accord or conflict
4143 One cannot obey a rule 'privately', because that is a practice, not the same as thinking one is obeying
7092 If individuals can't tell if they are following a rule, how does a community do it? [Grayling]
18. Thought / C. Content / 6. Broad Content
4138 Is white simple, or does it consist of the colours of the rainbow?
7055 Externalist accounts of mental content begin in Wittgenstein [Heil]
18. Thought / D. Concepts / 3. Ontology of Concepts / b. Concepts as abilities
12576 Possessing a concept is knowing how to go on [Peacocke]
4157 Concepts direct our interests and investigations, and express those interests
12606 Man learns the concept of the past by remembering
18. Thought / D. Concepts / 4. Structure of Concepts / h. Family resemblance
4141 Various games have a 'family resemblance', as their similarities overlap and criss-cross
18. Thought / D. Concepts / 5. Concepts and Language / a. Concepts and language
7084 What can be said is what can be thought, so language shows the limits of thought [Grayling]
19. Language / A. Nature of Meaning / 1. Meaning
23450 Wittgenstein rejected his earlier view that the form of language is the form of the world [Morris,M]
19. Language / A. Nature of Meaning / 2. Meaning as Mental
23481 Propositions assemble a world experimentally, like the model of a road accident
23482 The 'form' of the picture is its possible combinations
18283 Language pictures the essence of the world
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
8172 To understand a proposition means to know what is the case if it is true
18725 A proposition draws a line around the facts which agree with it
19. Language / A. Nature of Meaning / 5. Meaning as Verification
7086 Good philosophy asserts science, and demonstrates the meaninglessness of metaphysics
18282 You can't believe it if you can't imagine a verification for it
18728 The meaning of a proposition is the mode of its verification
4150 Asking about verification is only one way of asking about the meaning of a proposition
19. Language / A. Nature of Meaning / 6. Meaning as Use
6567 For Wittgenstein, words are defined by their use, just as chess pieces are [Fogelin]
4137 In the majority of cases the meaning of a word is its use in the language
6169 We do not achieve meaning and understanding in our heads, but in the world [Rowlands]
4155 We all seem able to see quite clearly how sentences represent things when we use them
19. Language / A. Nature of Meaning / 7. Meaning Holism / a. Sentence meaning
18705 Words function only in propositions, like levers in a machine
19. Language / A. Nature of Meaning / 7. Meaning Holism / b. Language holism
4142 To understand a sentence means to understand a language
19. Language / A. Nature of Meaning / 10. Denial of Meanings
4721 If you are not certain of any fact, you cannot be certain of the meaning of your words either
4149 We don't have 'meanings' in our minds in addition to verbal expressions
4156 Make the following experiment: say "It's cold here" and mean "It's warm here"
19. Language / B. Reference / 1. Reference theories
4145 How do words refer to sensations?
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
4140 The standard metre in Paris is neither one metre long nor not one metre long
19. Language / C. Assigning Meanings / 4. Compositionality
23511 Propositions use old expressions for a new sense
23488 Propositions are understood via their constituents
19. Language / D. Propositions / 1. Propositions
18711 A proposition is any expression which can be significantly negated
19. Language / D. Propositions / 2. Abstract Propositions / b. Propositions as possible worlds
23486 Pictures are possible situations in logical space
19. Language / D. Propositions / 4. Mental Propositions
23490 A thought is mental constituents that relate to reality as words do
19. Language / F. Communication / 4. Private Language
23497 Solipsism is correct, but can only be shown, not said, by the limits of my personal language
4136 To imagine a language means to imagine a form of life
6166 Was Wittgenstein's problem between individual and community, or between occasions for an individual? [Rowlands]
7875 If a brilliant child invented a name for a private sensation, it couldn't communicate it
4146 We cannot doublecheck mental images for correctness (or confirm news with many copies of the paper)
4147 If we only named pain by our own case, it would be like naming beetles by looking in a private box
5659 If the reference is private, that is incompatible with the sense being public [Scruton]
4152 Getting from perceptions to words cannot be a private matter; the rules need an institution of use
19. Language / F. Communication / 6. Interpreting Language / a. Translation
23489 We translate by means of proposition constituents, not by whole propositions
19. Language / F. Communication / 6. Interpreting Language / b. Indeterminate translation
6318 The doctrine of indeterminacy of translation seems implied by the later Wittgenstein [Quine]
19. Language / F. Communication / 6. Interpreting Language / c. Principle of charity
4144 Common human behaviour enables us to interpret an unknown language
11049 To communicate, language needs agreement in judgment as well as definition
20. Action / A. Definition of Action / 3. Actions and Events
6658 What is left over if I subtract my arm going up from my raising my arm?
21. Aesthetics / A. Aesthetic Experience / 2. Aesthetic Attitude
6606 Consider: "Imagine this butterfly exactly as it is, but ugly instead of beautiful"
22. Metaethics / A. Value / 1. Nature of Value / c. Objective value
2942 The sense of the world must lie outside the world
22. Metaethics / C. Ethics Foundations / 1. Nature of Ethics / b. Defining ethics
2943 Ethics cannot be put into words
25. Social Practice / F. Life Issues / 4. Suicide
4678 Absolute prohibitions are the essence of ethics, and suicide is the most obvious example
26. Natural Theory / D. Laws of Nature / 11. Against Laws of Nature
18733 Laws of nature are an aspect of the phenomena, and are just our mode of description
29. Religion / D. Religious Issues / 1. Religious Commitment / b. Religious Meaning
4151 Grammar tells what kind of object anything is - and theology is a kind of grammar
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
4159 The human body is the best picture of the human soul