14024
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Truthmaker has problems with generalisation, non-existence claims, and property instantiations [Crisp,TM]
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Full Idea:
Truthmaker is controversial: what of truths like 'all ravens are black', or 'there are no unicorns'. And 'John is tall' is not made true by John or the property of being tall, but by the fusion of the two, but what could this non-mereological fusion be?
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From:
Thomas M. Crisp (Presentism [2003], 3.4)
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A reaction:
A first move is to include modal facts (or possible worlds) among the truthmakers. The unicorns are tricky, and seem to need all of actuality as their truthmaker. I don't see the tallness difficulty. Predication is odd, but so what?
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13165
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Geometrical proofs do not show causes, as when we prove a triangle contains two right angles [Proclus]
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Full Idea:
Geometry does not ask 'why?' ..When from the exterior angle equalling two opposite interior angles it is shown that the interior angles make two right angles, this is not a causal demonstration. With no exterior angle they still equal two right angles.
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From:
Proclus (Commentary on Euclid's 'Elements' [c.452], p.161-2), quoted by Paolo Mancosu - Explanation in Mathematics §5
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A reaction:
A very nice example. It is hard to imagine how one might demonstrate the cause of the angles making two right angles. If you walk, turn left x°, then turn left y°, then turn left z°, and x+y+z=180°, you end up going in the original direction.
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20653
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Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson]
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Full Idea:
There are six 'reductive levels' in science: social groups, (multicellular) living things, cells, molecules, atoms, and elementary particles.
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From:
report of H.Putnam/P.Oppenheim (Unity of Science as a Working Hypothesis [1958]) by Peter Watson - Convergence 10 'Intro'
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A reaction:
I have the impression that fields are seen as more fundamental that elementary particles. What is the status of the 'laws' that are supposed to govern these things? What is the status of space and time within this picture?
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9569
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The origin of geometry started in sensation, then moved to calculation, and then to reason [Proclus]
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Full Idea:
It is unsurprising that geometry was discovered in the necessity of Nile land measurement, since everything in the world of generation goes from imperfection to perfection. They would naturally pass from sense-perception to calculation, and so to reason.
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From:
Proclus (Commentary on Euclid's 'Elements' [c.452]), quoted by Charles Chihara - A Structural Account of Mathematics 9.12 n55
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A reaction:
The last sentence is the core of my view on abstraction, that it proceeds by moving through levels of abstraction, approaching more and more general truths.
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14020
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'Eternalism' is the thesis that reality includes past, present and future entities [Crisp,TM]
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Full Idea:
I use the term Eternalism for the thesis that reality includes past, present and future entities. (It is sometimes used for the view that all propositions have their truth-value eternally - it is always true or never true).
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From:
Thomas M. Crisp (Presentism [2003], Intro n.1)
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A reaction:
'Eternalism' strikes me as an excellent word for the former meaning, so I shall promote that, and quietly forget the second one. The idea that the future exists has always stuck in my craw, and the belief that Napoleon still exists strikes me as a weird.
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14022
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The only three theories are Presentism, Dynamic (A-series) Eternalism and Static (B-series) Eternalism [Crisp,TM]
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Full Idea:
Three theories exhaust the options on time: presentism, dynamic eternalism (eternalism with the tensed dynamic A-series view of time, and the totality of events changing over time), and static eternalism (eternalism with the B-series).
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From:
Thomas M. Crisp (Presentism [2003], 2.4)
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A reaction:
I think the idea that reality is Static Eternalism is just a misunderstanding, arising from our imaginative ability to take a lofty objective overview of a very fluid reality. The other two are the serious candidates. Present, or Growing-block.
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