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All the ideas for 'Frege philosophy of mathematics', 'Axiomatic Theories of Truth' and 'Enquiry Conc Human Understanding'

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159 ideas

1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
The observation of human blindness and weakness is the result of all philosophy [Hume]
1. Philosophy / F. Analytic Philosophy / 4. Conceptual Analysis
If we suspect that a philosophical term is meaningless, we should ask what impression it derives from [Hume]
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Analysis rests on natural language, but its ideal is a framework which revises language [Halbach]
1. Philosophy / G. Scientific Philosophy / 1. Aims of Science
All experimental conclusions assume that the future will be like the past [Hume]
2. Reason / D. Definition / 2. Aims of Definition
An explicit definition enables the elimination of what is defined [Halbach]
2. Reason / D. Definition / 7. Contextual Definition
A contextual definition permits the elimination of the expression by a substitution [Dummett]
2. Reason / E. Argument / 3. Analogy
All reasoning concerning matters of fact is based on analogy (with similar results of similar causes) [Hume]
Don't trust analogies; they are no more than a guideline [Halbach]
3. Truth / A. Truth Problems / 1. Truth
Truth axioms prove objects exist, so truth doesn't seem to be a logical notion [Halbach]
Truth-value 'gluts' allow two truth values together; 'gaps' give a partial conception of truth [Halbach]
3. Truth / A. Truth Problems / 2. Defining Truth
Any definition of truth requires a metalanguage [Halbach]
Traditional definitions of truth often make it more obscure, rather than less [Halbach]
If people have big doubts about truth, a definition might give it more credibility [Halbach]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / c. Meta-language for truth
Semantic theories avoid Tarski's Theorem by sticking to a sublanguage [Halbach]
3. Truth / F. Semantic Truth / 2. Semantic Truth
Disquotational truth theories are short of deductive power [Halbach]
3. Truth / G. Axiomatic Truth / 1. Axiomatic Truth
Axiomatic truth doesn't presuppose a truth-definition, though it could admit it at a later stage [Halbach]
To axiomatise Tarski's truth definition, we need a binary predicate for his 'satisfaction' [Halbach]
Compositional Truth CT has the truth of a sentence depending of the semantic values of its constituents [Halbach]
The main semantic theories of truth are Kripke's theory, and revisions semantics [Halbach]
Gödel numbering means a theory of truth can use Peano Arithmetic as its base theory [Halbach]
Truth axioms need a base theory, because that is where truth issues arise [Halbach]
CT proves PA consistent, which PA can't do on its own, so CT is not conservative over PA [Halbach]
We know a complete axiomatisation of truth is not feasible [Halbach]
A theory is 'conservative' if it adds no new theorems to its base theory [Halbach, by PG]
The Tarski Biconditional theory TB is Peano Arithmetic, plus truth, plus all Tarski bi-conditionals [Halbach]
Theories of truth are 'typed' (truth can't apply to sentences containing 'true'), or 'type-free' [Halbach]
3. Truth / G. Axiomatic Truth / 2. FS Truth Axioms
Friedman-Sheard is type-free Compositional Truth, with two inference rules for truth [Halbach]
3. Truth / G. Axiomatic Truth / 3. KF Truth Axioms
Kripke-Feferman theory KF axiomatises Kripke fixed-points, with Strong Kleene logic with gluts [Halbach]
The KF is much stronger deductively than FS, which relies on classical truth [Halbach]
The KF theory is useful, but it is not a theory containing its own truth predicate [Halbach]
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
Deflationism says truth is a disquotation device to express generalisations, adding no new knowledge [Halbach]
The main problem for deflationists is they can express generalisations, but not prove them [Halbach]
Deflationists say truth is just for expressing infinite conjunctions or generalisations [Halbach]
Compositional Truth CT proves generalisations, so is preferred in discussions of deflationism [Halbach]
Some say deflationism is axioms which are conservative over the base theory [Halbach]
4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
In Strong Kleene logic a disjunction just needs one disjunct to be true [Halbach]
In Weak Kleene logic there are 'gaps', neither true nor false if one component lacks a truth value [Halbach]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Every attempt at formal rigour uses some set theory [Halbach]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
The underestimated costs of giving up classical logic are found in mathematical reasoning [Halbach]
In classical logic, logical truths are valid formulas; in higher-order logics they are purely logical [Dummett]
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
A theory is some formulae and all of their consequences [Halbach]
5. Theory of Logic / K. Features of Logics / 3. Soundness
Normally we only endorse a theory if we believe it to be sound [Halbach]
Soundness must involve truth; the soundness of PA certainly needs it [Halbach]
You cannot just say all of Peano arithmetic is true, as 'true' isn't part of the system [Halbach]
5. Theory of Logic / L. Paradox / 1. Paradox
Many new paradoxes may await us when we study interactions between frameworks [Halbach]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
The liar paradox applies truth to a negated truth (but the conditional will serve equally) [Halbach]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
A prime number is one which is measured by a unit alone [Dummett]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
Addition of quantities is prior to ordering, as shown in cyclic domains like angles [Dummett]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / a. Units
A number is a multitude composed of units [Dummett]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / e. Counting by correlation
We understand 'there are as many nuts as apples' as easily by pairing them as by counting them [Dummett]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
The compactness theorem can prove nonstandard models of PA [Halbach]
The global reflection principle seems to express the soundness of Peano Arithmetic [Halbach]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
To reduce PA to ZF, we represent the non-negative integers with von Neumann ordinals [Halbach]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
The identity of a number may be fixed by something outside structure - by counting [Dummett]
Numbers aren't fixed by position in a structure; it won't tell you whether to start with 0 or 1 [Dummett]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
Reason assists experience in discovering laws, and in measuring their application [Hume]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / b. Type theory
Set theory was liberated early from types, and recent truth-theories are exploring type-free [Halbach]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Set theory isn't part of logic, and why reduce to something more complex? [Dummett]
7. Existence / A. Nature of Existence / 4. Abstract Existence
We can't think about the abstract idea of triangles, but only of particular triangles [Hume]
7. Existence / C. Structure of Existence / 2. Reduction
That Peano arithmetic is interpretable in ZF set theory is taken by philosophers as a reduction [Halbach]
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
The distinction of concrete/abstract, or actual/non-actual, is a scale, not a dichotomy [Dummett]
7. Existence / D. Theories of Reality / 2. Realism
Realism is just the application of two-valued semantics to sentences [Dummett]
8. Modes of Existence / C. Powers and Dispositions / 7. Against Powers
We cannot form an idea of a 'power', and the word is without meaning [Hume]
8. Modes of Existence / E. Nominalism / 1. Nominalism / a. Nominalism
Nominalism assumes unmediated mental contact with objects [Dummett]
9. Objects / A. Existence of Objects / 2. Abstract Objects / a. Nature of abstracta
The existence of abstract objects is a pseudo-problem [Dummett]
9. Objects / A. Existence of Objects / 2. Abstract Objects / c. Modern abstracta
Abstract objects nowadays are those which are objective but not actual [Dummett]
It is absurd to deny the Equator, on the grounds that it lacks causal powers [Dummett]
'We've crossed the Equator' has truth-conditions, so accept the Equator - and it's an object [Dummett]
9. Objects / A. Existence of Objects / 2. Abstract Objects / d. Problems with abstracta
Abstract objects need the context principle, since they can't be encountered directly [Dummett]
9. Objects / F. Identity among Objects / 2. Defining Identity
Content is replaceable if identical, so replaceability can't define identity [Dummett, by Dummett]
Frege introduced criteria for identity, but thought defining identity was circular [Dummett]
10. Modality / A. Necessity / 2. Nature of Necessity
Maybe necessity is a predicate, not the usual operator, to make it more like truth [Halbach]
10. Modality / B. Possibility / 6. Probability
We transfer the frequency of past observations to our future predictions [Hume]
10. Modality / B. Possibility / 7. Chance
There is no such thing as chance [Hume]
11. Knowledge Aims / A. Knowledge / 4. Belief / a. Beliefs
Belief is stronger, clearer and steadier than imagination [Hume]
11. Knowledge Aims / A. Knowledge / 4. Belief / b. Elements of beliefs
Belief is just a particular feeling attached to ideas of objects [Hume]
Belief can't be a concept plus an idea, or we could add the idea to fictions [Hume]
11. Knowledge Aims / A. Knowledge / 4. Belief / d. Cause of beliefs
'Natural beliefs' are unavoidable, whatever our judgements [Hume, by Strawson,G]
Beliefs are built up by resemblance, contiguity and causation [Hume]
12. Knowledge Sources / A. A Priori Knowledge / 9. A Priori from Concepts
Relations of ideas are known by thought, independently from the world [Hume]
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / e. Primary/secondary critique
If secondary qualities (e.g. hardness) are in the mind, so are primary qualities like extension [Hume]
12. Knowledge Sources / B. Perception / 3. Representation
It never occurs to people that they only experience representations, not the real objects [Hume]
12. Knowledge Sources / D. Empiricism / 1. Empiricism
All ideas are copies of impressions [Hume]
All reasoning about facts is causal; nothing else goes beyond memory and senses [Hume]
If books don't relate ideas or explain facts, commit them to the flames [Hume]
All objects of enquiry are Relations of Ideas, or Matters of Fact [Hume]
Hume is loose when he says perceptions of different strength are different species [Reid on Hume]
Impressions are our livelier perceptions, Ideas the less lively ones [Hume]
12. Knowledge Sources / D. Empiricism / 2. Associationism
All ideas are connected by Resemblance, Contiguity in time or place, and Cause and Effect [Hume]
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
Only madmen dispute the authority of experience [Hume]
We can only invent a golden mountain by combining experiences [Hume]
We cannot form the idea of something we haven't experienced [Hume]
How could Adam predict he would drown in water or burn in fire? [Hume]
You couldn't reason at all if you lacked experience [Hume]
When definitions are pushed to the limit, only experience can make them precise [Hume]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
Hume mistakenly lumps sensations and perceptions together as 'impressions' [Scruton on Hume]
If a person had a gap in their experience of blue shades, they could imaginatively fill it in [Hume]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / c. Empirical foundations
Reasons for belief must eventually terminate in experience, or they are without foundation [Hume]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
There is no certain supreme principle, or infallible rule of inference [Hume]
13. Knowledge Criteria / C. External Justification / 7. Testimony
We think testimony matches reality because of experience, not some a priori connection [Hume]
Good testimony needs education, integrity, motive and agreement [Hume, by PG]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Reason can never show that experiences are connected to external objects [Hume]
Mitigated scepticism draws attention to the limitations of human reason, and encourages modesty [Hume]
13. Knowledge Criteria / D. Scepticism / 2. Types of Scepticism
Mitigated scepticism sensibly confines our enquiries to the narrow capacity of human understanding [Hume]
13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism
Examples of illusion only show that sense experience needs correction by reason [Hume]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
It is a very extravagant aim of the sceptics to destroy reason and argument by means of reason and argument [Hume]
The main objection to scepticism is that no good can come of it [Hume]
14. Science / C. Induction / 2. Aims of Induction
We assume similar secret powers behind similar experiences, such as the nourishment of bread [Hume]
14. Science / C. Induction / 3. Limits of Induction
All inferences from experience are effects of custom, not reasoning [Hume]
Reason cannot show why reliable past experience should extend to future times and remote places [Hume]
Induction can't prove that the future will be like the past, since induction assumes this [Hume]
If we infer causes from repetition, this explains why we infer from a thousand objects what we couldn't infer from one [Hume]
Fools, children and animals all learn from experience [Hume]
14. Science / C. Induction / 4. Reason in Induction
Hume just shows induction isn't deduction [Williams,M on Hume]
Premises can support an argument without entailing it [Pollock/Cruz on Hume]
15. Nature of Minds / C. Capacities of Minds / 7. Seeing Resemblance
A picture of a friend strengthens our idea of him, by resemblance [Hume]
General ideas are the connection by resemblance to some particular [Hume]
Hume does not distinguish real resemblances among degrees of resemblance [Shoemaker on Hume]
15. Nature of Minds / C. Capacities of Minds / 8. Remembering Contiguity
When I am close to (contiguous with) home, I feel its presence more nearly [Hume]
15. Nature of Minds / C. Capacities of Minds / 9. Perceiving Causation
Our awareness of patterns of causation is too important to be left to slow and uncertain reasoning [Hume]
An object made by a saint is the best way to produce thoughts of him [Hume]
16. Persons / F. Free Will / 5. Against Free Will
The doctrine of free will arises from a false sensation we have of freedom in many actions [Hume]
16. Persons / F. Free Will / 7. Compatibilism
Liberty is merely acting according to the will, which anyone can do if they are not in chains [Hume]
Hume makes determinism less rigid by removing the necessity from causation [Trusted on Hume]
18. Thought / D. Concepts / 4. Structure of Concepts / i. Conceptual priority
Maybe a concept is 'prior' to another if it can be defined without the second concept [Dummett]
An argument for conceptual priority is greater simplicity in explanation [Dummett]
18. Thought / E. Abstraction / 1. Abstract Thought
Abstract terms are acceptable as long as we know how they function linguistically [Dummett]
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
There is no reason why abstraction by equivalence classes should be called 'logical' [Dummett, by Tait]
We arrive at the concept 'suicide' by comparing 'Cato killed Cato' with 'Brutus killed Brutus' [Dummett]
18. Thought / E. Abstraction / 8. Abstractionism Critique
To abstract from spoons (to get the same number as the forks), the spoons must be indistinguishable too [Dummett]
19. Language / C. Assigning Meanings / 5. Fregean Semantics
Fregean semantics assumes a domain articulated into individual objects [Dummett]
19. Language / D. Propositions / 4. Mental Propositions
We need propositions to ascribe the same beliefs to people with different languages [Halbach]
20. Action / B. Preliminaries of Action / 2. Willed Action / a. Will to Act
Only experience teaches us about our wills [Hume]
20. Action / C. Motives for Action / 4. Responsibility for Actions
Praise and blame can only be given if an action proceeds from a person's character and disposition [Hume]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / g. Moral responsibility
If you deny all necessity and causation, then our character is not responsible for our crime [Hume]
Repentance gets rid of guilt, which shows that responsibility arose from the criminal principles in the mind [Hume]
25. Social Practice / A. Freedoms / 3. Free speech
No government has ever suffered by being too tolerant of philosophy [Hume]
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / b. Limited purposes
We can discover some laws of nature, but never its ultimate principles and causes [Hume]
26. Natural Theory / C. Causation / 1. Causation
A priori it looks as if a cause could have absolutely any effect [Hume]
If a singular effect is studied, its cause can only be inferred from the types of events involved [Hume]
26. Natural Theory / C. Causation / 7. Eliminating causation
Hume never even suggests that there is no such thing as causation [Hume, by Strawson,G]
26. Natural Theory / C. Causation / 8. Particular Causation / b. Causal relata
At first Hume said qualities are the causal entities, but later he said events [Hume, by Davidson]
26. Natural Theory / C. Causation / 9. General Causation / a. Constant conjunction
It is only when two species of thing are constantly conjoined that we can infer one from the other [Hume]
Hume says we can only know constant conjunctions, not that that's what causation IS [Hume, by Strawson,G]
In both of Hume's definitions, causation is extrinsic to the sequence of events [Psillos on Hume]
Hume's definition of cause as constantly joined thoughts can't cover undiscovered laws [Ayer on Hume]
A cause is either similar events following one another, or an experience always suggesting a second experience [Hume]
No causes can be known a priori, but only from experience of constant conjunctions [Hume]
26. Natural Theory / C. Causation / 9. General Causation / c. Counterfactual causation
Cause is where if the first object had not been, the second had not existed [Hume]
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
In observing causes we can never observe any necessary connections or binding qualities [Hume]
Hume never shows how a strong habit could generate the concept of necessity [Harré/Madden on Hume]
Hume's regularity theory of causation is epistemological; he believed in some sort of natural necessity [Hume, by Strawson,G]
27. Natural Reality / C. Space / 3. Points in Space
Why should the limit of measurement be points, not intervals? [Dummett]
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
It can never be a logical contradiction to assert the non-existence of something thought to exist [Hume]
28. God / B. Proving God / 3. Proofs of Evidence / c. Teleological Proof critique
You can't infer the cause to be any greater than its effect [Hume]
28. God / B. Proving God / 3. Proofs of Evidence / e. Miracles
To establish a miracle the falseness of the evidence must be a greater miracle than the claimed miraculous event [Hume]
A miracle violates laws which have been established by continuous unchanging experience, so should be ignored [Hume]
All experience must be against a supposed miracle, or it wouldn't be called 'a miracle' [Hume]
28. God / C. Attitudes to God / 4. God Reflects Humanity
The idea of an infinite, intelligent, wise and good God arises from augmenting the best qualities of our own minds [Hume]