Combining Philosophers

All the ideas for Tim Mawson, Richard Dedekind and Dorothy Edgington

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57 ideas

2. Reason / D. Definition / 9. Recursive Definition
Dedekind proved definition by recursion, and thus proved the basic laws of arithmetic [Dedekind, by Potter]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
Conditional Proof is only valid if we accept the truth-functional reading of 'if' [Edgington]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / d. Infinite Sets
An infinite set maps into its own proper subset [Dedekind, by Reck/Price]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
We have the idea of self, and an idea of that idea, and so on, so infinite ideas are available [Dedekind, by Potter]
4. Formal Logic / G. Formal Mereology / 1. Mereology
Dedekind originally thought more in terms of mereology than of sets [Dedekind, by Potter]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
Numbers are free creations of the human mind, to understand differences [Dedekind]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
Dedekind defined the integers, rationals and reals in terms of just the natural numbers [Dedekind, by George/Velleman]
Ordinals can define cardinals, as the smallest ordinal that maps the set [Dedekind, by Heck]
Order, not quantity, is central to defining numbers [Dedekind, by Monk]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Dedekind's ordinals are just members of any progression whatever [Dedekind, by Russell]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
We want the essence of continuity, by showing its origin in arithmetic [Dedekind]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts
A cut between rational numbers creates and defines an irrational number [Dedekind]
Dedekind's axiom that his Cut must be filled has the advantages of theft over honest toil [Dedekind, by Russell]
Dedekind says each cut matches a real; logicists say the cuts are the reals [Dedekind, by Bostock]
I say the irrational is not the cut itself, but a new creation which corresponds to the cut [Dedekind]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
In counting we see the human ability to relate, correspond and represent [Dedekind]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / f. Arithmetic
Arithmetic is just the consequence of counting, which is the successor operation [Dedekind]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / b. Mark of the infinite
A system S is said to be infinite when it is similar to a proper part of itself [Dedekind]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / l. Limits
If x changes by less and less, it must approach a limit [Dedekind]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
Dedekind gives a base number which isn't a successor, then adds successors and induction [Dedekind, by Hart,WD]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
Zero is a member, and all successors; numbers are the intersection of sets satisfying this [Dedekind, by Bostock]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Categoricity implies that Dedekind has characterised the numbers, because it has one domain [Rumfitt on Dedekind]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Induction is proved in Dedekind, an axiom in Peano; the latter seems simpler and clearer [Dedekind, by Russell]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Dedekind originated the structuralist conception of mathematics [Dedekind, by MacBride]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / b. Varieties of structuralism
Dedekindian abstraction talks of 'positions', where Cantorian abstraction talks of similar objects [Dedekind, by Fine,K]
9. Objects / A. Existence of Objects / 3. Objects in Thought
A thing is completely determined by all that can be thought concerning it [Dedekind]
10. Modality / A. Necessity / 1. Types of Modality
There are two families of modal notions, metaphysical and epistemic, of equal strength [Edgington]
10. Modality / A. Necessity / 5. Metaphysical Necessity
Metaphysical possibility is discovered empirically, and is contrained by nature [Edgington]
10. Modality / A. Necessity / 6. Logical Necessity
Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion [Edgington]
Logical necessity is epistemic necessity, which is the old notion of a priori [Edgington, by McFetridge]
An argument is only valid if it is epistemically (a priori) necessary [Edgington]
10. Modality / B. Possibility / 6. Probability
Truth-functional possibilities include the irrelevant, which is a mistake [Edgington]
A thing works like formal probability if all the options sum to 100% [Edgington]
Conclusion improbability can't exceed summed premise improbability in valid arguments [Edgington]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
It is a mistake to think that conditionals are statements about how the world is [Edgington]
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
Simple indicatives about past, present or future do seem to form a single semantic kind [Edgington]
Maybe forward-looking indicatives are best classed with the subjunctives [Edgington]
There are many different conditional mental states, and different conditional speech acts [Edgington]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
Truth-function problems don't show up in mathematics [Edgington]
Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]
Inferring conditionals from disjunctions or negated conjunctions gives support to truth-functionalism [Edgington]
The truth-functional view makes conditionals with unlikely antecedents likely to be true [Edgington]
Doctor:'If patient still alive, change dressing'; Nurse:'Either dead patient, or change dressing'; kills patient! [Edgington]
10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
A conditional does not have truth conditions [Edgington]
X believes 'if A, B' to the extent that A & B is more likely than A & ¬B [Edgington]
Non-truth-functionalist say 'If A,B' is false if A is T and B is F, but deny that is always true for TT,FT and FF [Edgington]
I say "If you touch that wire you'll get a shock"; you don't touch it. How can that make the conditional true? [Edgington]
10. Modality / B. Possibility / 8. Conditionals / e. Supposition conditionals
Conditionals express what would be the outcome, given some supposition [Edgington]
On the supposition view, believe if A,B to the extent that A&B is nearly as likely as A [Edgington]
10. Modality / B. Possibility / 8. Conditionals / f. Pragmatics of conditionals
Truth-functionalists support some conditionals which we assert, but should not actually believe [Edgington]
Does 'If A,B' say something different in each context, because of the possibiites there? [Edgington]
18. Thought / E. Abstraction / 3. Abstracta by Ignoring
Dedekind said numbers were abstracted from systems of objects, leaving only their position [Dedekind, by Dummett]
We derive the natural numbers, by neglecting everything of a system except distinctness and order [Dedekind]
18. Thought / E. Abstraction / 8. Abstractionism Critique
Dedekind has a conception of abstraction which is not psychologistic [Dedekind, by Tait]
25. Social Practice / C. Rights / 1. Basis of Rights
Rights are moral significance, or liberty, or right not to be restrained, or entitlement [Mawson]