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
If you hope to improve the world, all you can do is improve yourself
While faith is a passion (as Kierkegaard says), wisdom is passionless
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
1. Philosophy / D. Nature of Philosophy / 1. Philosophy
What we cannot speak about we must pass over in silence
A philosopher is outside any community of ideas
1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
The main problem of philosophy is what can and cannot be thought and expressed
I say (contrary to Wittgenstein) that philosophy expresses what we thought we must be silent about
Philosophy is a battle against the bewitchment of our intelligence by means of language
1. Philosophy / D. Nature of Philosophy / 4. Aims of Philosophy / d. Philosophy as puzzles
Philosophical tries to be rid of certain intellectual puzzles, irrelevant to daily life
1. Philosophy / D. Nature of Philosophy / 5. Hopes for Philosophy
If a question can be framed at all, it is also possible to answer it
1. Philosophy / D. Nature of Philosophy / 6. Despair over Philosophy
What is your aim in philosophy? - To show the fly the way out of the fly-bottle
The 'Tractatus' is a masterpiece of anti-philosophy
Philosophers express puzzlement, but don't clearly state the puzzle
1. Philosophy / F. Analytic Philosophy / 1. Analysis
We already know what we want to know, and analysis gives us no new facts
All complex statements can be resolved into constituents and descriptions
1. Philosophy / F. Analytic Philosophy / 2. Conceptual Analysis
Analysis complicates a statement, but only as far as the complexity of its meaning
1. Philosophy / F. Analytic Philosophy / 4. Ordinary Language
We don't need a theory of truth, because we use the word perfectly well
The limits of my language means the limits of my world
2. Reason / B. Laws of Thought / 3. Non-Contradiction
The problem is to explain the role of contradiction in social life
2. Reason / B. Laws of Thought / 6. Ockham's Razor
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
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
Grammar says that saying 'sound is red' is not false, but nonsense
Talking nonsense is not following the rules
3. Truth / A. Truth Problems / 2. Defining Truth
There is no theory of truth, because it isn't a concept
3. Truth / B. Truthmakers / 2. Truthmaker Relation
The best account of truth-making is isomorphism
3. Truth / B. Truthmakers / 11. Truthmaking and Correspondence
All truths have truth-makers, but only atomic truths correspond to them
3. Truth / C. Correspondence Truth / 1. Correspondence Truth
Wittgenstein's picture theory is the best version of the correspondence theory of truth
Language is [propositions-elementary propositions-names]; reality is [facts-states of affairs-objects]
Pictures reach out to or feel reality, touching at the edges, correlating in its parts
All thought has the logical form of reality
3. Truth / H. Deflationary Truth / 1. Redundant Truth
'It is true that this follows' means simply: this follows
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
We can dispense with self-evidence, if language itself prevents logical mistakes
In logic nothing is hidden
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Wittgenstein is right that logic is just tautologies
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
Logic is a priori because it is impossible to think illogically
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
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
The propositions of logic are analytic tautologies
5. Theory of Logic / C. Ontology of Logic / 2. Platonism in Logic
Wittgenstein convinced Russell that logic is tautologies, not Platonic forms
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
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
Contradiction is between two rules, not between rule and reality
5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
The sign of identity is not allowed in 'Tractatus'
The identity sign is not essential in logical notation, if every sign has a different meaning
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
A statement's logical form derives entirely from its constituents
Wittgenstein says we want the grammar of problems, not their first-order logical structure
Apparent logical form may not be real logical form
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
'And' and 'not' are non-referring terms, which do not represent anything
My fundamental idea is that the 'logical constants' do not represent
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / c. not
We may correctly use 'not' without making the rule explicit
Negations are not just reversals of truth-value, since that can happen without negation
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
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
'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
Naming is a preparation for description
A person's name doesn't mean their body; bodies don't sit down, and their existence can be denied
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
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
A name is primitive, and its meaning is the object
5. Theory of Logic / H. Proof Systems / 1. Proof Systems
Logical proof just explicates complicated tautologies
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Logical truths are just 'by-products' of the introduction rules for logical constants
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
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
'This sentence is false' sends us in a looping search for its proposition
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
In mathematics everything is algorithm and nothing is meaning
6. Mathematics / A. Nature of Mathematics / 3. Numbers / g. Real numbers
We don't get 'nearer' to something by adding decimals to 1.1412... (root-2)
6. Mathematics / A. Nature of Mathematics / 4. The Infinite / a. The Infinite
Infinity is not a number, so doesn't say how many; it is the property of a law
6. Mathematics / B. Foundations for Mathematics / 4. Definitions of Number / a. Defining numbers
The concept of number is just what all numbers have in common
A number is a repeated operation
6. Mathematics / B. Foundations for Mathematics / 5. Mathematics as Set Theory / b. Mathematics is not set theory
The theory of classes is superfluous in mathematics
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Two and one making three has the necessity of logical inference
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Wittgenstein hated logicism, and described is as a cancerous growth
7. Existence / A. Nature of Existence / 1. Nature of Existence
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
The 'Tractatus' is an extreme example of 'Logical Atomism'
7. Existence / D. Theories of Reality / 7. Facts / b. Types of fact
There are no positive or negative facts; these are just the forms of propositions
8. Modes of Existence / A. Relations / 2. Internal Relations
The order of numbers is an internal relation, not an external one
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
Using 'green' is a commitment to future usage of 'green'
8. Modes of Existence / E. Nominalism / 2. Resemblance Nominalism
Various games have a 'family resemblance', as their similarities overlap and criss-cross
9. Objects / B. Unity of Objects / 2. Substance / b. Need for substance
We accept substance, to avoid infinite backwards chains of meaning
9. Objects / D. Essence of Objects / 5. Essence as Kind
Essence is expressed by grammar
9. Objects / F. Identity among Objects / 1. Concept of Identity
Identity is not a relation between objects
9. Objects / F. Identity among Objects / 5. Self-Identity
Two things can't be identical, and self-identity is an empty concept
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
It at least makes sense to say two objects have all their properties in common
10. Modality / A. Necessity / 3. Types of Necessity
The only necessity is logical necessity
10. Modality / C. Sources of Modality / 3. Necessity by Convention
For each necessity in the world there is an arbitrary rule of language
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
To know an object you must know all its possible occurrences
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
Two objects may only differ in being different
11. Knowledge Aims / A. Knowledge / 2. Understanding
Understanding is translation, into action or into other symbols
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
The belief that fire burns is like the fear that it burns
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
Are sense-data the material of which the universe is made?
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
If the truth doesn't follow from self-evidence, then self-evidence cannot justify a truth
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
Logic and maths can't say anything about the world, since, as tautologies, they are consistent with all realities
12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective
Logic is a priori because we cannot think illogically
12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory
We live in sense-data, but talk about physical objects
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
As sense-data are necessarily private, they are attacked by Wittgenstein's objections
12. Knowledge Sources / D. Empiricism / 1. Empiricism
Good philosophy asserts science, and demonstrates the meaninglessness of metaphysics
12. Knowledge Sources / E. Direct Knowledge / 1. Intuition
How do I decide when to accept or obey an intuition?
12. Knowledge Sources / E. Direct Knowledge / 3. Memory
If you remember wrongly, then there must be some other criterion than your remembering
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
Foundations need not precede other beliefs
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
Causes of beliefs are irrelevant to their contents
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Doubts can't exist if they are inexpressible or unanswerable
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
One can mistrust one's own senses, but not one's own beliefs
Total doubt can't even get started
14. Science / B. Scientific Theories / 3. Instrumentalism
The 'Tractatus' is instrumentalist about laws of nature
14. Science / C. Induction / 2. Aims of Induction
Induction accepts the simplest law that fits our experiences
14. Science / D. Explanation / 1. Explanation / b. Aims of explanation
Explanation and understanding are the same
Explanation gives understanding by revealing the full multiplicity of the thing
14. Science / D. Explanation / 2. Types of Explanation / d. Lawlike explanations
The modern worldview is based on the illusion that laws explain nature
14. Science / D. Explanation / 2. Types of Explanation / h. Explanations by mechanism
A machine strikes us as being a rule of movement
14. Science / D. Explanation / 3. Best Explanation / a. Best explanation
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
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
It is irresponsible to generalise from my own case of pain to other people's
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
If a lion could talk, it would be nothing like other lions
If a lion could talk, we could not understand him
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
16. Persons / D. Self and Body / 2. A Priori Self
The subject stands outside our understanding of the world
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?
18. Thought / A. Modes of Thought / 1. Thought
Thought is an activity which we perform by the expression of it
18. Thought / A. Modes of Thought / 10. Rule Following
An 'inner process' stands in need of outward criteria
One cannot obey a rule 'privately', because that is a practice, not the same as thinking one is obeying
If individuals can't tell if they are following a rule, how does a community do it?
Every course of action can either accord or conflict with a rule, so there is no accord or conflict
18. Thought / C. Content / 6. Broad Content
Externalist accounts of mental content begin in Wittgenstein
Is white simple, or does it consist of the colours of the rainbow?
18. Thought / D. Concepts / 3. Ontology of Concepts / b. Concepts as abilities
Possessing a concept is knowing how to go on
Concepts direct our interests and investigations, and express those interests
Man learns the concept of the past by remembering
18. Thought / D. Concepts / 5. Concepts and Language / a. Concepts and language
What can be said is what can be thought, so language shows the limits of thought
19. Language / A. Nature of Meaning / 1. Meaning
Make the following experiment: say "It's cold here" and mean "It's warm here"
19. Language / A. Nature of Meaning / 2. Meaning as Mental
Language pictures the essence of the world
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
To understand a proposition means to know what is the case if it is true
A proposition draws a line around the facts which agree with it
19. Language / A. Nature of Meaning / 5. Meaning as Verification
You can't believe it if you can't imagine a verification for it
The meaning of a proposition is the mode of its verification
Good philosophy should show that metaphysical remarks use meaningless signs
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
For Wittgenstein, words are defined by their use, just as chess pieces are
We do not achieve meaning and understanding in our heads, but in the world
We all seem able to see quite clearly how sentences represent things when we use them
In the majority of cases the meaning of a word is its use in the language
19. Language / A. Nature of Meaning / 7. Meaning Holism / a. Sentence meaning
Words function only in propositions, like levers in a machine
19. Language / A. Nature of Meaning / 7. Meaning Holism / b. Lanugage holism
To understand a sentence means to understand a language
19. Language / A. Nature of Meaning / 10. Denial of Meanings
We don't have 'meanings' in our minds in addition to verbal expressions
If you are not certain of any fact, you cannot be certain of the meaning of your words either
19. Language / C. Reference / 1. Reference theories
How do words refer to sensations?
19. Language / C. Reference / 3. Direct Reference / b. Causal reference
The standard metre in Paris is neither one metre long nor not one metre long
19. Language / D. Propositions / 1. Propositions
A proposition is any expression which can be significantly negated
19. Language / F. Communication / 4. Private Language
Was Wittgenstein's problem between individual and community, or between occasions for an individual?
If a brilliant child invented a name for a private sensation, it couldn't communicate it
We cannot doublecheck mental images for correctness (or confirm news with many copies of the paper)
To imagine a language means to imagine a form of life
If we only named pain by our own case, it would be like naming beetles by looking in a private box
If the reference is private, that is incompatible with the sense being public
Getting from perceptions to words cannot be a private matter; the rules need an institution of use
19. Language / F. Communication / 6. Interpreting Language / b. Indeterminate translation
The doctrine of indeterminacy of translation seems implied by the later Wittgenstein
19. Language / F. Communication / 6. Interpreting Language / c. Principle of charity
Common human behaviour enables us to interpret an unknown language
To communicate, language needs agreement in judgment as well as definition
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?
21. Aesthetics / A. Aesthetic Experience / 2. Aesthetic Attitude
Consider: "Imagine this butterfly exactly as it is, but ugly instead of beautiful"
22. Metaethics / A. Value / 1. Nature of Value / d. Objective value
The sense of the world must lie outside the world
22. Metaethics / C. Ethics Foundations / 1. Nature of Ethics / b. Defining ethics
Ethics cannot be put into words
24. Applied Ethics / C. Death Issues / 4. Suicide
Absolute prohibitions are the essence of ethics, and suicide is the most obvious example
26. Natural Theory / D. Laws of Nature / 12. Against Laws of Nature
Laws of nature are an aspect of the phenomena, and are just our mode of description
29. Religion / A. Religious Thought / 2. Religious Meaning
Grammar tells what kind of object anything is - and theology is a kind of grammar
29. Religion / E. Immortality / 2. Soul
The human body is the best picture of the human soul