Economics Dictionary of ArgumentsHome![]() | |||
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Physics: Physics is the study of matter, energy, and their interactions. It is the fundamental science that seeks to understand how the natural world works. See also Nature, Natural laws, Method, Measurments, Observation, Regularities._____________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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Pierre Duhem on Physics - Dictionary of Arguments
I XXI Physics/Duhem: the work of the physicist in 4 steps: 1. Definition and measurement of the physical quantities (also combined quantities) the symbols of the theory are given a physical meaning only to the extent that measurement methods for the quantities are given. 2. Formulation of hypotheses. Here, quantities are linked together. I XXII 3. The mathematical development of the theory e.g. the slowed down motion on the inclined plane is the responsibility of the logician and the mathematician alone. 4. Review by experiment. "Consistency with experience is the only criterion of truth for a physical theory." I 150 Theoretical Physics/Duhem: cannot grasp the sensually perceptible phenomena. It cannot therefore decide whether these properties are qualitative or quantitative. Theoretical physics confines itself to representing perceptible phenomena through signs, by symbols. It does not capture the reality of things. I 275 Physics/Duhem: must respect the mathematical rules strictly. The mathematical symbols have only meaning under properly determined conditions. To define these symbols is to enumerate the conditions. E.g. because of the definition, an absolute temperature can only be positive, the mass of a body invariable. Postulates: The theory has the principle of postulates, i.e. theorems which it can express as it likes, if there are no contradictions within the postulates, or between them. Only such rules weigh on the construction of the theory. The physical theory can take any path that is logical. In particular, it is free to give no account of the experimental facts. This is no longer the case when the theory is fully developed. Then it becomes necessary to compare the group of mathematical theorems with the group of experimental data. It may then turn out that it must be discarded, although it is logically correct because it is physically false because of the observation. >Theories, >Observation, >Observation language, >Theoretical terms. I 276 It is a mistake that all the conclusions made by the mathematician have a physical meaning. Similarly, (falsely) any calculation carried out during a measurement procedure would have to have a correspondence in a property of the examined body. That is not the case. Only the concluding formulas deal with the observed objects. E.g. Dissociation of a perfect gas mixture into its elements, which were regarded as perfect gases. I 277 Measuring: e.g. no thermometer can determine the highest temperature. The symbol for absolute temperature does not correspond to any of the measuring methods. What is called a perfect gas in thermodynamics is only an approximate picture of a real gas. >Experiments, >Idealization._____________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. |
Duh I P. Duhem La théorie physique, son objet et sa structure, Paris 1906 German Edition: Ziel und Struktur der physikalischen Theorien Hamburg 1998 |