Combining Texts

All the ideas for 'fragments/reports', 'Notes on John Wilkins' and 'Notice of Fine's 'Limits of Abstraction''

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3 ideas

9. Objects / D. Essence of Objects / 14. Knowledge of Essences
Essence is the distinct thinkability of anything [Leibniz]
     Full Idea: (Essence) is the distinct thinkability (cogitabilitas) of anything.
     From: Gottfried Leibniz (Notes on John Wilkins [1672], A6.2.487-8), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 1
     A reaction: A very original remark from the young Leibniz. It is neutral as to whether this is a real feature of objects, or a feature of human mental capacities. Presumably accidental features are thinkable, so 'distinct' is the key word.
13. Knowledge Criteria / E. Relativism / 2. Knowledge as Convention
By nature people are close to one another, but culture drives them apart [Hippias]
     Full Idea: I regard you all as relatives - by nature, not by convention. By nature like is akin to like, but convention is a tyrant over humankind and often constrains people to act contrary to nature.
     From: Hippias (fragments/reports [c.430 BCE]), quoted by Plato - Protagoras 337c8
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
Abstraction theories build mathematics out of second-order equivalence principles [Cook/Ebert]
     Full Idea: A theory of abstraction is any account that reconstructs mathematical theories using second-order abstraction principles of the form: §xFx = §xGx iff E(F,G). We ignore first-order abstraction principles such as Frege's direction abstraction.
     From: R Cook / P Ebert (Notice of Fine's 'Limits of Abstraction' [2004], 1)
     A reaction: Presumably part of the neo-logicist programme, which also uses such principles. The function § (extension operator) 'provides objects corresponding to the argument concepts'. The aim is to build mathematics, rather than the concept of a 'rabbit'.