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All the ideas for 'Frege philosophy of mathematics', 'The Approach to Metaphysics' and 'Travels in Four Dimensions'

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58 ideas

1. Philosophy / E. Nature of Metaphysics / 4. Metaphysics as Science
Metaphysics rests on observations, but ones so common we hardly notice them [Peirce]
2. Reason / D. Definition / 7. Contextual Definition
A contextual definition permits the elimination of the expression by a substitution [Dummett]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
In classical logic, logical truths are valid formulas; in higher-order logics they are purely logical [Dummett]
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 / 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 / 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 / 3. Being / d. Non-being
A thing which makes no difference seems unlikely to exist [Le Poidevin]
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 / 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]
14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
In addition to causal explanations, they can also be inferential, or definitional, or purposive [Le Poidevin]
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 / C. Assigning Meanings / 9. Indexical Semantics
We don't just describe a time as 'now' from a private viewpoint, but as a fact about the world [Le Poidevin]
26. Natural Theory / C. Causation / 1. Causation
The logical properties of causation are asymmetry, transitivity and irreflexivity [Le Poidevin]
27. Natural Reality / C. Space / 3. Points in Space
Why should the limit of measurement be points, not intervals? [Dummett]
We can identify unoccupied points in space, so they must exist [Le Poidevin]
If spatial points exist, then they must be stationary, by definition [Le Poidevin]
27. Natural Reality / C. Space / 4. Substantival Space
Absolute space explains actual and potential positions, and geometrical truths [Le Poidevin]
27. Natural Reality / C. Space / 5. Relational Space
For relationists moving an object beyond the edge of space creates new space [Le Poidevin]
27. Natural Reality / C. Space / 6. Space-Time
We distinguish time from space, because it passes, and it has a unique present moment [Le Poidevin]
27. Natural Reality / D. Time / 1. Nature of Time / e. Eventless time
Since nothing occurs in a temporal vacuum, there is no way to measure its length [Le Poidevin]
Temporal vacuums would be unexperienced, unmeasured, and unending [Le Poidevin]
27. Natural Reality / D. Time / 2. Passage of Time / b. Rate of time
Time can't speed up or slow down, so it doesn't seem to be a 'process' [Le Poidevin]
27. Natural Reality / D. Time / 2. Passage of Time / f. Tenseless (B) series
To say that the past causes the present needs them both to be equally real [Le Poidevin]
The B-series doesn't seem to allow change [Le Poidevin]
If the B-universe is eternal, why am I trapped in a changing moment of it? [Le Poidevin]
27. Natural Reality / D. Time / 2. Passage of Time / g. Time's arrow
An ordered series can be undirected, but time favours moving from earlier to later [Le Poidevin]
If time's arrow is causal, how can there be non-simultaneous events that are causally unconnected? [Le Poidevin]
If time's arrow is psychological then different minds can impose different orders on events [Le Poidevin]
There are Thermodynamic, Psychological and Causal arrows of time [Le Poidevin]
Presumably if time's arrow is thermodynamic then time ends when entropy is complete [Le Poidevin]
If time is thermodynamic then entropy is necessary - but the theory says it is probable [Le Poidevin]
Time's arrow is not causal if there is no temporal gap between cause and effect [Le Poidevin]
27. Natural Reality / D. Time / 2. Passage of Time / i. Time and motion
Instantaneous motion is an intrinsic disposition to be elsewhere [Le Poidevin]
The dynamic view of motion says it is primitive, and not reducible to objects, properties and times [Le Poidevin]
27. Natural Reality / D. Time / 2. Passage of Time / k. Temporal truths
If the present could have diverse pasts, then past truths can't have present truthmakers [Le Poidevin]
27. Natural Reality / D. Time / 3. Parts of Time / a. Beginning of time
The present is the past/future boundary, so the first moment of time was not present [Le Poidevin]
27. Natural Reality / D. Time / 3. Parts of Time / c. Intervals
The primitive parts of time are intervals, not instants [Le Poidevin]
27. Natural Reality / D. Time / 3. Parts of Time / e. Present moment
If time is infinitely divisible, then the present must be infinitely short [Le Poidevin]
27. Natural Reality / E. Cosmology / 10. Multiverse
The multiverse is distinct time-series, as well as spaces [Le Poidevin]
28. God / A. Divine Nature / 5. God and Time
How could a timeless God know what time it is? So could God be both timeless and omniscient? [Le Poidevin]