Combining Texts

All the ideas for 'fragments/reports', 'Barcan Formulae' and 'The Problem of Possibilia'

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5 ideas

4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
Barcan:nothing comes into existence; Converse:nothing goes out; Both:domain is unchanging [Vervloesem]
     Full Idea: Intuitively, the Barcan formula says that nothing comes into existence when moving from a possible world to an alternative world. The converse says that nothing goes out of existence. Together they say the domain of quantification is fixed for all worlds.
     From: Koen Vervloesem (Barcan Formulae [2010])
     A reaction: Stated so clearly, they sound absurd. The sensible idea, I suppose, is that you can refer to all the things from any world, but that doesn't mean they are possible. Shades of Meinong. 'Square circles' are not possible.
10. Modality / B. Possibility / 1. Possibility
Possible states of affairs are not propositions; a proposition can't be a state of affairs! [Fine,K]
     Full Idea: Possible states of affairs have often been taken to be propositions, but this cannot be correct, since any possible state of affairs is possibly a state of affairs, but no proposition is possibly a state of affairs.
     From: Kit Fine (The Problem of Possibilia [2003], 2)
     A reaction: The point is, presumably, that the state of affairs cannot be the proposition itself, but (at least) what the proposition refers to. I can't see any objection to that.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
The actual world is a possible world, so we can't define possible worlds as 'what might have been' [Fine,K]
     Full Idea: A possible world can't be defined (by Stalnaker and Plantinga) as a way the world might have been, because a possible world is possibly the world, yet no way the world might have been is possibly the world.
     From: Kit Fine (The Problem of Possibilia [2003], 2)
     A reaction: His point is that any definition of a possible world must cover the actual world, because that is one of them. 'Might have been' is not applicable to the actual world. It seems a fairly important starting point for discussion of possible worlds.
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.