Philosophy Dictionary of ArgumentsHome
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| Models, philosophy, logic: A model is obtained when a logical formula provides true statements by inserting objects instead of the free variables. One problem is the exclusion of unintended models. See also model theory._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. | |||
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Bernulf Kanitscheider on Models - Dictionary of Arguments
I 184 Model/Theory/Cosmology/Kanitscheider: The semantic carrier of the idealizations is the so-called model object. No physical theory refers directly to the unconceptual reality! The model of relativistic cosmology is that of the ideal perfect fluid. In large-scale view the galaxies are treated as a gas of not interacting particles. Then one even looks away from the particle structure of the gas to come to a perfect idealized liquid. This representation matter is characterized only by the four-velocity uα, the density of the mass-energy ρ and the pressure p more. ((s) >four-vector/Feynman). The velocity uα refers to an observer which is at rest relative to the material substrate, thus for which the neighboring galaxies have no motion. The density is also determined by this system. The kinetic pressure of the galaxies p makes itself felt when the density of kinetic energy reaches the order of magnitude of the rest mass density of the galaxies, which alone dominates in the universe today. In density and pressure all forms of radiation are included. In the present balance, however, neither matter nor radiation pressure weighs heavily. In the early days of the universe, however, radiation probably played a dominant role. The selection of the three parameters is by no means logically necessary! It is the question whether one decides to allow less highly symmetrical models for the description. For our extreme simplification we get the I 185 energy stress tensor: (5) Tαβ = (ρ + p)uαuβ + pgαβ u: velocity ρ: density p: kinetic pressure g: metrics From the ontological point of view it is remarkable that in the expression for the matter (right side) neither the metric gαβ appears. This can be seen as an indication against Mach's principle that the Tαβ cannot be formulated without the gαβ. But this speaks for the fact that one cannot strictly separate geometry and matter in Einstein's theory! The ontological duplicity is only seductively suggested by the causal way of speaking, according to which the matter distribution produces the space structure. Matter/Cosmos/Einstein/Kanitscheider: in the simplified model one obtains the static distribution, where of the 10 components only T00 = γ remains, and this density is also independent of time. >Model theory._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. Translations: Dictionary of Arguments The note [Concept/Author], [Author1]Vs[Author2] or [Author]Vs[term] resp. "problem:"/"solution:", "old:"/"new:" and "thesis:" is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition. |
Kanitsch I B. Kanitscheider Kosmologie Stuttgart 1991 Kanitsch II B. Kanitscheider Im Innern der Natur Darmstadt 1996 |
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> Counter arguments against Kanitscheider
> Counter arguments in relation to Models
Ed. Martin Schulz, access date 2024-04-16