Combining Texts

All the ideas for 'Isagoge ('Introduction')', 'Experimental Researches in Electricity' and 'Letters to Thomasius'

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4 ideas

8. Modes of Existence / D. Universals / 1. Universals

15034	Are genera and species real or conceptual? bodies or incorporeal? in sensibles or separate from them? [Porphyry]
	Full Idea: I shall beg off talking of a) whether genera and species are real or situated in bare thoughts alone, b) whether as real they are bodies or incorporeals, and c) whether they are separated or in sensibles and have their reality in connection with them.
	From: Porphyry (Isagoge ('Introduction') [c.295], (2))
	A reaction: This passage, picking up on Aristotle, seems to be the original source that grew into the medievel debate about universals. It seems to rather neatly lay out the agenda for the universals debate which is still with us.

9. Objects / D. Essence of Objects / 1. Essences of Objects

13432	The essence of a circle is the equality of its radii [Leibniz]
	Full Idea: The essence of a circle consists in the equality of all lines drawn from its centre to its circumference.
	From: Gottfried Leibniz (Letters to Thomasius [1669], 1669)
	A reaction: Compare Locke in Idea 13431 and Spinoza in Idea 13073 on the essence of geometrical figures. A key question is whether the essence is in the simplest definition, or in a complex and wide-ranging account, e.g. including conic sections for circles.

27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement

12696	Bodies are recreated in motion, and don't exist in intervening instants [Leibniz]
	Full Idea: I have demonstrated that whatever moves is continuously created and that bodies are nothing at any time between the instants in motion.
	From: Gottfried Leibniz (Letters to Thomasius [1669], 1669.04), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 1
	A reaction: Leibniz is a little over-confident about what he has 'demonstrated', but I think (from this remark) that he would not have been displeased with quantum theory, and the notion of a 'quantum leap' and a 'Planck time'. A 'conatus' is a 'smallest motion'.

27. Natural Reality / B. Modern Physics / 2. Electrodynamics / b. Fields

15314	Faraday's single field of variable forces introduces a criterion of Unity into what is ultimate [Faraday, by Harré/Madden]
	Full Idea: In Faraday lines of force picture the directional structure of powers,...so the fundamental entity is a single, unified field. ...A new criterion of the ultimate has stepped in: Unity. The universal field is still the final explanation, but not invariant.
	From: report of Michael Faraday (Experimental Researches in Electricity [1859]) by Harré,R./Madden,E.H. - Causal Powers 9.II.B
	A reaction: Almost Parmenides, except that the field is not invariant. But that was always the ancient objection to the One - that it offered no explanation of change.