Combining Philosophers

All the ideas for William W. Tait, Mark Colyvan and David S. Oderberg

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52 ideas

1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
Analytic philosophy focuses too much on forms of expression, instead of what is actually said [Tait]
2. Reason / D. Definition / 5. Genus and Differentia
'Animal' is a genus and 'rational' is a specific difference [Oderberg]
Definition distinguishes one kind from another, and individuation picks out members of the kind [Oderberg]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Rejecting double negation elimination undermines reductio proofs [Colyvan]
Showing a disproof is impossible is not a proof, so don't eliminate double negation [Colyvan]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
The null set was doubted, because numbering seemed to require 'units' [Tait]
4. Formal Logic / F. Set Theory ST / 7. Natural Sets
We can have a series with identical members [Tait]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim proved his result for a first-order sentence, and Skolem generalised it [Colyvan]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Mathematics must be based on axioms, which are true because they are axioms, not vice versa [Tait, by Parsons,C]
Axioms are 'categorical' if all of their models are isomorphic [Colyvan]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
The Aristotelian view is that numbers depend on (and are abstracted from) other things [Oderberg]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinal numbers represent order relations [Colyvan]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Intuitionists only accept a few safe infinities [Colyvan]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / j. Infinite divisibility
Infinitesimals were sometimes zero, and sometimes close to zero [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Reducing real numbers to rationals suggested arithmetic as the foundation of maths [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Transfinite induction moves from all cases, up to the limit ordinal [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Most mathematical proofs are using set theory, but without saying so [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Structuralism say only 'up to isomorphism' matters because that is all there is to it [Colyvan]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
If 'in re' structures relies on the world, does the world contain rich enough structures? [Colyvan]
7. Existence / A. Nature of Existence / 3. Being / a. Nature of Being
Being is substantial/accidental, complete/incomplete, necessary/contingent, possible, relative, intrinsic.. [Oderberg]
8. Modes of Existence / B. Properties / 13. Tropes / b. Critique of tropes
If tropes are in space and time, in what sense are they abstract? [Oderberg]
8. Modes of Existence / C. Powers and Dispositions / 4. Powers as Essence
We need to distinguish the essential from the non-essential powers [Oderberg]
9. Objects / B. Unity of Objects / 2. Substance / e. Substance critique
Empiricists gave up 'substance', as unknowable substratum, or reducible to a bundle [Oderberg]
9. Objects / D. Essence of Objects / 1. Essences of Objects
Essences are real, about being, knowable, definable and classifiable [Oderberg, by PG]
9. Objects / D. Essence of Objects / 3. Individual Essences
Nominalism is consistent with individual but not with universal essences [Oderberg]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
Essentialism is the main account of the unity of objects [Oderberg]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
Essence is not explanatory but constitutive [Oderberg]
9. Objects / D. Essence of Objects / 9. Essence and Properties
Properties are not part of an essence, but they flow from it [Oderberg]
9. Objects / D. Essence of Objects / 15. Against Essentialism
Could we replace essence with collections of powers? [Oderberg]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
Leibniz's Law is an essentialist truth [Oderberg]
10. Modality / B. Possibility / 4. Potentiality
Bodies have act and potency, the latter explaining new kinds of existence [Oderberg]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Realism about possible worlds is circular, since it needs a criterion of 'possible' [Oderberg]
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Necessity of identity seems trivial, because it leaves out the real essence [Oderberg]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
Rigid designation has at least three essentialist presuppositions [Oderberg]
14. Science / C. Induction / 6. Bayes's Theorem
Probability supports Bayesianism better as degrees of belief than as ratios of frequencies [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
Mathematics can reveal structural similarities in diverse systems [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / f. Necessity in explanations
Mathematics can show why some surprising events have to occur [Colyvan]
14. Science / D. Explanation / 2. Types of Explanation / m. Explanation by proof
Proof by cases (by 'exhaustion') is said to be unexplanatory [Colyvan]
Reductio proofs do not seem to be very explanatory [Colyvan]
If inductive proofs hold because of the structure of natural numbers, they may explain theorems [Colyvan]
Can a proof that no one understands (of the four-colour theorem) really be a proof? [Colyvan]
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
Mathematical generalisation is by extending a system, or by abstracting away from it [Colyvan]
18. Thought / E. Abstraction / 2. Abstracta by Selection
Abstraction is 'logical' if the sense and truth of the abstraction depend on the concrete [Tait]
Cantor and Dedekind use abstraction to fix grammar and objects, not to carry out proofs [Tait]
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
Abstraction may concern the individuation of the set itself, not its elements [Tait]
18. Thought / E. Abstraction / 8. Abstractionism Critique
Why should abstraction from two equipollent sets lead to the same set of 'pure units'? [Tait]
If abstraction produces power sets, their identity should imply identity of the originals [Tait]
26. Natural Theory / A. Speculations on Nature / 3. Natural Function
Essence is the source of a thing's characteristic behaviour [Oderberg]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / e. The One
What makes Parmenidean reality a One rather than a Many? [Oderberg]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / a. Scientific essentialism
The real essentialist is not merely a scientist [Oderberg]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / e. Anti scientific essentialism
The reductionism found in scientific essentialism is mistaken [Oderberg]