Combining Texts

All the ideas for 'Abstract Objects', 'Naming and Necessity preface' and 'Principles of Arithmetic, by a new method'

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21 ideas

4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
Possible worlds allowed the application of set-theoretic models to modal logic [Kripke]
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
A man has two names if the historical chains are different - even if they are the same! [Kripke]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
All models of Peano axioms are isomorphic, so the models all seem equally good for natural numbers [Cartwright,R on Peano]
PA concerns any entities which satisfy the axioms [Peano, by Bostock]
Peano axioms not only support arithmetic, but are also fairly obvious [Peano, by Russell]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
We can add Reflexion Principles to Peano Arithmetic, which assert its consistency or soundness [Halbach on Peano]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Arithmetic can have even simpler logical premises than the Peano Axioms [Russell on Peano]
9. Objects / A. Existence of Objects / 2. Abstract Objects / d. Problems with abstracta
How we refer to abstractions is much less clear than how we refer to other things [Rosen]
9. Objects / F. Identity among Objects / 1. Concept of Identity
With the necessity of self-identity plus Leibniz's Law, identity has to be an 'internal' relation [Kripke]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
The indiscernibility of identicals is as self-evident as the law of contradiction [Kripke]
10. Modality / C. Sources of Modality / 1. Sources of Necessity
I don't think possible worlds reductively reveal the natures of modal operators etc. [Kripke]
10. Modality / D. Knowledge of Modality / 2. A Priori Contingent
The very act of designating of an object with properties gives knowledge of a contingent truth [Kripke]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
Instead of talking about possible worlds, we can always say "It is possible that.." [Kripke]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Probability with dice uses possible worlds, abstractions which fictionally simplify things [Kripke]
18. Thought / E. Abstraction / 2. Abstracta by Selection
The Way of Abstraction used to say an abstraction is an idea that was formed by abstracting [Rosen]
18. Thought / E. Abstraction / 5. Abstracta by Negation
Nowadays abstractions are defined as non-spatial, causally inert things [Rosen]
Chess may be abstract, but it has existed in specific space and time [Rosen]
Sets are said to be abstract and non-spatial, but a set of books can be on a shelf [Rosen]
18. Thought / E. Abstraction / 6. Abstracta by Conflation
Conflating abstractions with either sets or universals is a big claim, needing a big defence [Rosen]
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
Functional terms can pick out abstractions by asserting an equivalence relation [Rosen]
Abstraction by equivalence relationships might prove that a train is an abstract entity [Rosen]