Combining Philosophers

All the ideas for Hugo Grotius, Penelope Maddy and Peter van Inwagen

expand these ideas     |    start again     |     specify just one area for these philosophers


112 ideas

2. Reason / D. Definition / 12. Paraphrase
We could refer to tables as 'xs that are arranged tablewise' [Inwagen]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
'Forcing' can produce new models of ZFC from old models [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
A Large Cardinal Axiom would assert ever-increasing stages in the hierarchy [Maddy]
New axioms are being sought, to determine the size of the continuum [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / b. Axiom of Extensionality I
The Axiom of Extensionality seems to be analytic [Maddy]
Extensional sets are clearer, simpler, unique and expressive [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
The Axiom of Infinity states Cantor's breakthrough that launched modern mathematics [Maddy]
Infinite sets are essential for giving an account of the real numbers [Maddy]
Axiom of Infinity: completed infinite collections can be treated mathematically [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / g. Axiom of Powers VI
The Power Set Axiom is needed for, and supported by, accounts of the continuum [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / i. Axiom of Foundation VIII
The Axiom of Foundation says every set exists at a level in the set hierarchy [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
Efforts to prove the Axiom of Choice have failed [Maddy]
Modern views say the Choice set exists, even if it can't be constructed [Maddy]
A large array of theorems depend on the Axiom of Choice [Maddy]
The Axiom of Choice paradoxically allows decomposing a sphere into two identical spheres [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
Axiom of Reducibility: propositional functions are extensionally predicative [Maddy]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets
The Iterative Conception says everything appears at a stage, derived from the preceding appearances [Maddy]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / f. Limitation of Size
Limitation of Size is a vague intuition that over-large sets may generate paradoxes [Maddy]
4. Formal Logic / F. Set Theory ST / 7. Natural Sets
The master science is physical objects divided into sets [Maddy]
Maddy replaces pure sets with just objects and perceived sets of objects [Maddy, by Shapiro]
4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory
What in the real world could ground the distinction between the sets {A,{A,B}} and {B,{A,B}}? [Inwagen]
4. Formal Logic / G. Formal Mereology / 1. Mereology
Mereology is 'nihilistic' (just atoms) or 'universal' (no restrictions on what is 'whole') [Inwagen, by Varzi]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Henkin semantics is more plausible for plural logic than for second-order logic [Maddy]
5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
Critics of if-thenism say that not all starting points, even consistent ones, are worth studying [Maddy]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
The 'Law' of Excluded Middle needs all propositions to be definitely true or definitely false [Inwagen]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
'Propositional functions' are propositions with a variable as subject or predicate [Maddy]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
Variables are just like pronouns; syntactic explanations get muddled over dummy letters [Inwagen]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Hilbert's geometry and Dedekind's real numbers were role models for axiomatization [Maddy]
If two mathematical themes coincide, that suggest a single deep truth [Maddy]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / b. The Heap paradox ('Sorites')
There are no heaps [Inwagen]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
Completed infinities resulted from giving foundations to calculus [Maddy]
Cantor and Dedekind brought completed infinities into mathematics [Maddy]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / g. Continuum Hypothesis
Every infinite set of reals is either countable or of the same size as the full set of reals [Maddy]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
Infinity has degrees, and large cardinals are the heart of set theory [Maddy]
For any cardinal there is always a larger one (so there is no set of all sets) [Maddy]
An 'inaccessible' cardinal cannot be reached by union sets or power sets [Maddy]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / l. Limits
Theorems about limits could only be proved once the real numbers were understood [Maddy]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / c. Fregean numbers
In the ZFC hierarchy it is impossible to form Frege's set of all three-element sets [Maddy]
The extension of concepts is not important to me [Maddy]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
Frege solves the Caesar problem by explicitly defining each number [Maddy]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Set theory (unlike the Peano postulates) can explain why multiplication is commutative [Maddy]
Standardly, numbers are said to be sets, which is neat ontology and epistemology [Maddy]
Numbers are properties of sets, just as lengths are properties of physical objects [Maddy]
A natural number is a property of sets [Maddy, by Oliver]
Making set theory foundational to mathematics leads to very fruitful axioms [Maddy]
Unified set theory gives a final court of appeal for mathematics [Maddy]
Set theory brings mathematics into one arena, where interrelations become clearer [Maddy]
Identifying geometric points with real numbers revealed the power of set theory [Maddy]
The line of rationals has gaps, but set theory provided an ordered continuum [Maddy]
Set-theory tracks the contours of mathematical depth and fruitfulness [Maddy]
Mathematics rests on the logic of proofs, and on the set theoretic axioms [Maddy]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / b. Mathematics is not set theory
Number theory doesn't 'reduce' to set theory, because sets have number properties [Maddy]
Sets exist where their elements are, but numbers are more like universals [Maddy]
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / b. Against mathematical platonism
If mathematical objects exist, how can we know them, and which objects are they? [Maddy]
6. Mathematics / C. Sources of Mathematics / 2. Intuition of Mathematics
Intuition doesn't support much mathematics, and we should question its reliability [Maddy, by Shapiro]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
We know mind-independent mathematical truths through sets, which rest on experience [Maddy, by Jenkins]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / b. Indispensability of mathematics
Scientists posit as few entities as possible, but set theorist posit as many as possible [Maddy]
Maybe applications of continuum mathematics are all idealisations [Maddy]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
The connection of arithmetic to perception has been idealised away in modern infinitary mathematics [Maddy]
6. Mathematics / C. Sources of Mathematics / 5. Numbers as Adjectival
Number words are unusual as adjectives; we don't say 'is five', and numbers always come first [Maddy]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
We can get arithmetic directly from HP; Law V was used to get HP from the definition of number [Maddy]
7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff
I reject talk of 'stuff', and treat it in terms of particles [Inwagen]
7. Existence / D. Theories of Reality / 10. Vagueness / d. Vagueness as linguistic
Singular terms can be vague, because they can contain predicates, which can be vague [Inwagen]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
The theoretical indispensability of atoms did not at first convince scientists that they were real [Maddy]
9. Objects / A. Existence of Objects / 1. Physical Objects
Material objects are in space and time, move, have a surface and mass, and are made of some stuff [Inwagen]
Maybe table-shaped particles exist, but not tables [Inwagen, by Lowe]
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
Nihilism says composition between single things is impossible [Inwagen]
If there are no tables, but tables are things arranged tablewise, the denial of tables is a contradiction [Liggins on Inwagen]
Actions by artefacts and natural bodies are disguised cooperations, so we don't need them [Inwagen]
9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
Every physical thing is either a living organism or a simple [Inwagen]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
The statue and lump seem to share parts, but the statue is not part of the lump [Inwagen]
If you knead clay you make an infinite series of objects, but they are rearrangements, not creations [Inwagen]
9. Objects / C. Structure of Objects / 3. Matter of an Object
I assume matter is particulate, made up of 'simples' [Inwagen]
9. Objects / C. Structure of Objects / 5. Composition of an Object
If contact causes composition, do two colliding balls briefly make one object? [Inwagen]
If bricks compose a house, that is at least one thing, but it might be many things [Inwagen]
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
I think parthood involves causation, and not just a reasonably stable spatial relationship [Inwagen]
We can deny whole objects but accept parts, by referring to them as plurals within things [Inwagen, by Liggins]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
Special Composition Question: when is a thing part of something? [Inwagen]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
The essence of a star includes the released binding energy which keeps it from collapse [Inwagen]
9. Objects / D. Essence of Objects / 11. Essence of Artefacts
The persistence of artifacts always covertly involves intelligent beings [Inwagen]
9. Objects / E. Objects over Time / 7. Intermittent Objects
When an electron 'leaps' to another orbit, is the new one the same electron? [Inwagen]
9. Objects / E. Objects over Time / 9. Ship of Theseus
If you reject transitivity of vague identity, there is no Ship of Theseus problem [Inwagen]
9. Objects / F. Identity among Objects / 1. Concept of Identity
We should talk of the transitivity of 'identity', and of 'definite identity' [Inwagen]
10. Modality / C. Sources of Modality / 5. Modality from Actuality
Actuality proves possibility, but that doesn't explain how it is possible [Inwagen]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Counterparts reduce counterfactual identity to problems about similarity relations [Inwagen]
10. Modality / E. Possible worlds / 3. Transworld Objects / e. Possible Objects
A merely possible object clearly isn't there, so that is a defective notion [Inwagen]
Merely possible objects must be consistent properties, or haecceities [Inwagen]
15. Nature of Minds / C. Capacities of Minds / 6. Idealisation
Science idealises the earth's surface, the oceans, continuities, and liquids [Maddy]
16. Persons / F. Free Will / 7. Compatibilism
Determinism clashes with free will, as the past determines action, and is beyond our control [Inwagen, by Jackson]
20. Action / C. Motives for Action / 5. Action Dilemmas / c. Omissions
Nations are not obliged to help one-another, but are obliged not to harm one another [Grotius, by Tuck]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / d. Virtue theory critique
Virtue theory needs an external standard to judge behaviour and character [Inwagen, by Statman]
24. Political Theory / A. Basis of a State / 3. Natural Values / c. Natural rights
Everyone has a right of self-preservation, and harming others is usually unjustifiable [Grotius, by Tuck]
24. Political Theory / D. Ideologies / 5. Democracy / a. Nature of democracy
Democracy needs respect for individuality, but the 'community of friends' implies strict equality [Grotius]
25. Social Practice / A. Freedoms / 7. Freedom to leave
A person is free to renounce their state, as long as it is not a moment of crisis [Grotius, by Rousseau]
25. Social Practice / D. Justice / 2. The Law / c. Natural law
Grotius and Pufendorf based natural law on real (rather than idealised) humanity [Grotius, by Ford,JD]
A natural right of self-preservation is balanced by a natural law to avoid unnecessary harm [Grotius, by Tuck]
25. Social Practice / D. Justice / 2. The Law / d. Legal positivism
Grotius ignored elaborate natural law theories, preferring a basic right of self-preservation [Grotius, by Tuck]
25. Social Practice / E. Policies / 1. War / b. Justice in war
It is permissible in a just cause to capture a place in neutral territory [Grotius]
27. Natural Reality / B. Modern Physics / 3. Chromodynamics / a. Chromodynamics
The strong force pulls, but also pushes apart if nucleons get too close together [Inwagen]
27. Natural Reality / F. Chemistry / 2. Modern Elements
Is one atom a piece of gold, or is a sizable group of atoms required? [Inwagen]
27. Natural Reality / G. Biology / 2. Life
At the lower level, life trails off into mere molecular interaction [Inwagen]
The chemical reactions in a human life involve about sixteen elements [Inwagen]
Life is vague at both ends, but could it be totally vague? [Inwagen]
A tumour may spread a sort of life, but it is not a life, or an organism [Inwagen]
Being part of an organism's life is a matter of degree, and vague [Inwagen]
A flame is like a life, but not nearly so well individuated [Inwagen]
If God were to 'reassemble' my atoms of ten years ago, the result would certainly not be me [Inwagen]
Some events are only borderline cases of lives [Inwagen]
Unlike waves, lives are 'jealous'; it is almost impossible for them to overlap [Inwagen]
One's mental and other life is centred on the brain, unlike any other part of the body [Inwagen]
28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
Moral principles have some validity without a God commanding obedience [Grotius, by Mautner]
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
There is no reason to think that mere existence is a valuable thing [Inwagen]