Combining Texts

All the ideas for 'fragments/reports', 'The Problem of Counterfactual Conditionals' and 'Letters to Leibniz'

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4 ideas

4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
No one can conceive of a possible substance, apart from those which God has created [Arnauld]
     Full Idea: I am much mistaken if there is anyone who dares to say that he can conceive of a purely possible substance, …for although one talks so much of them, one never conceives them except according to the notion of those which God has created.
     From: Antoine Arnauld (Letters to Leibniz [1686], 1686.05.13), quoted by David Wiggins - Sameness and Substance 4.2
     A reaction: This idea cashes out in the 'necessitism' of Tim Williamson, and views on the Barcan formulae in modal logic.
10. Modality / B. Possibility / 9. Counterfactuals
Counterfactuals are true if logical or natural laws imply the consequence [Goodman, by McFetridge]
     Full Idea: Goodman's central idea was: 'If that match had been scratched, it would have lighted' is true if there are suitable truths from which, with the antecedent, the consequent can be inferred by means of a logical, or more typically natural, law.
     From: report of Nelson Goodman (The Problem of Counterfactual Conditionals [1947]) by Ian McFetridge - Logical Necessity: Some Issues §4
     A reaction: Goodman then discusses the problem of identifying the natural laws, and identifying the suitable truths. I'm inclined to think counterfactuals are vaguer than that; they are plausible if coherent reasons can be offered for the inference.
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
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
27. Natural Reality / G. Biology / 3. Evolution
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.