Combining Texts

All the ideas for 'fragments/reports', 'Letters to Wagner' and 'Elucidation of some points in E.Schrder'

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4 ideas

4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set

14238	A class is an aggregate of objects; if you destroy them, you destroy the class; there is no empty class [Frege]
	Full Idea: A class consists of objects; it is an aggregate, a collective unity, of them; if so, it must vanish when these objects vanish. If we burn down all the trees of a wood, we thereby burn down the wood. Thus there can be no empty class.
	From: Gottlob Frege (Elucidation of some points in E.Schröder [1895], p.212), quoted by Oliver,A/Smiley,T - What are Sets and What are they For?
	A reaction: This rests on Cantor's view of a set as a collection, rather than on Dedekind, which allows null and singleton sets.

26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature

1748	Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]
	Full Idea: Archelaus was the first person to say that the universe is boundless.
	From: report of Archelaus (fragments/reports [c.450 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 02.Ar.3

26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / a. Early Modern matter

19436	Bare or primary matter is passive; it is clothed or secondary matter which contains action [Leibniz]
	Full Idea: The active principle is not attributed by me to bare or primary matter, which is merely passive ...but to clothed or secondary matter which in addition contains a primitive entelechy, or active principle.
	From: Gottfried Leibniz (Letters to Wagner [1710], 1710 §2)
	A reaction: Secondary matter contains monads. The puzzling question is what primary matter consists of. It is not atoms, because it is infinitely divisible, and it seems to be composed of corpuscles. But what is it made of? Just gunge? He says it is 'flux'.

27. Natural Reality / G. Biology / 3. Evolution

5989	Archelaus said life began in a primeval slime [Archelaus, by Schofield]
	Full Idea: Archelaus wrote that life on Earth began in a primeval slime.
	From: report of Archelaus (fragments/reports [c.450 BCE]) by Malcolm Schofield - Archelaus
	A reaction: This sounds like a fairly clearcut assertion of the production of life by evolution. Darwin's contribution was to propose the mechanism for achieving it. We should honour the name of Archelaus for this idea.