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Taken from:
FOUNDATIONS OF PHYSICS BY ROBERT BRUCE LINDSAY, Ph.D. Associate Professor of Theoretical Physics, Brown University AND HENRY MARGENAU, Ph.D. Assistant Professor of Physics Yale University NEW YORK JOHN WILEY & SONS, Inc. LONDON: CHAPMAN & HALL, LIMITED, 1936 From the poster: Note the role that conventionalism and agreement play in the founding of a science by these authors. Why do the authors define physics as they do: the "task of physics as of all science is found in the coherent description of experience"? Do you hgave a better definition or characterization of physics? Is the notion of the "material world" really problematic? What would the realist say? What would the instrumentalist say? ------------------------------------------------------ --- p. 1 --- THE MEANING OF A PHYSICAL THEORY 1.1. The Data of Physics. Physics is concerned with a certain portion of human experience. From this experience the physicist constructs what he terms the physical world, a concept which arises from a peculiar combination of certain observed facts and the reasoning provoked by their perception. While most textbooks of physics set themselves the task of presenting to the student in the most adequate pedagogical manner the features of the physical world as they have been historically developed, it is the principal purpose of the present volume to conduct an inquiry into the logical constituents of these features, analyzing them into such elements as observed facts, definitions, postulates, and deductions. What, then, is experience, and how much of it concerns the physicist? A detailed answer to the first part of this question would lead us into the depths of philosophy, to which this book is not primarily devoted. Nevertheless, a few remarks on this point are necessary to avoid possible misconceptions. We shall at once assume the possibility of experience and knowledge as the metaphysical basis upon which any science fundamentally rests. Moreover, we shall accept the genuineness of the sense-perceptions of normal people and abstain from quarreling about the meaning of normality in this connection. Naturally, the physicist like all scientists must be forever on his guard against abnormal perceptions, but he has, we assume, objective criteria for detecting them. We must also grant the possibility of the exchange of knowledge, that is, the understanding of another's sense-perceptions and reflections in terms of one's own. A further assumption, however, must be made about experience before science as we know it becomes possible. Not only must there be agreement about it among normal people, but also it must exhibit a certain uniformity. That is, many sense-perceptions do not occur completely at random, but certain more or less well-defined groups of perceptions repeat themselves over and over again with only slight --- p. 2 --- 2 THE MEANING OF A PHYSICAL THEORY and often insignificant variations. The alternation of day and night with their attendant phenomena illustrates this point, and the reader will be able to supply other examples from all branches of science. There thus appears to be a kind of order in natural phenomena which is often expressed as the law of cause and effect: if a certain group of sense-perceptions appears a number of times associated with a second group, we expect that a repetition of the first group will always be associated with that of the second. This is not the place for a detailed discussion of the significance for physics of the assumption of uniformity in its various forms. We shall have occasion later (Chapter X) to investigate these matters more closely and are here introducing them merely as a means of initiating our discussion. Now, clearly, physics is not concerned with the whole body of human experience. How, then, are the data of physics selected? Before we come to this question, however, let us make quite plain that the task of physics as of all science is found in the coherent description of experience. Physics has nothing to say about a possible real world lying behind experience. It is extremely important to realize that, although physics rests upon the assumptions of the possibility of knowledge and the uniformity of experience, the other philosophical problems connected with realism and idealism have no significance for it. One often hears the statement that the task of physics is to describe or explain the behavior of the material world. We cannot help feeling that this is meant to imply the existence of such a world, though what the adjective "material" here means is by no means clear. The physicist has been striving for years to attach a clear meaning to the term matter, and undoubtedly we have reason to believe that the concept means much more to us today than to the physicists of fifty years ago. However, to have a clear understanding of a physical concept like matter is not at all equivalent to the assumption that there is a "real" world behind our sense-perceptions which is responsible for the existence of matter. There is perhaps no harm in such an assumption---in fact, certain minds may find that it enables them more firmly to grasp and feel confidence in physical theories; yet it must be stressed that the assumption is no necessary part of physics, and that in a logical development of the subject the safest course is to omit it entirely. It is possible, indeed, to take the view that adopting such an assumption as part of the physicist's stock-in trade involves a handicap. There is scarcely any use in believing in a real material world behind physical phenomena unless it is a permanent, unchanging affair toward the knowledge of which we progress with slow but certain steps. But our knowledge of it is based naturally --- p. 3 --- 1.1 THE DATA OF PHYSICS 3 on the prevailing physical theories. It seems as if the belief in such a world may tend to encourage too close adherence to reasonably successful physical theories with too small allowance for their necessary revision to meet the demands of new experience. Thus, the term "physical world" used in the introductory paragraph is not to be construed as being identical with real world. ----------------------------------- My definition of physics: Physics is the search for the smallest set of rules by which we can completely describe the behavior of inanimate matter under natural circumstances. Back when mechanics was thought to be the correct program to found all of physics, it made sense to think of matter as fundamental and irreducible, but since the advent of field theories this is not so meaningful, as the material particle itself can be modeled as a "localization" or accumulization of field, like the bunching up of a tablecloth. Patrick |
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Patrick Reany wrote:
Taken from: FOUNDATIONS OF PHYSICS [snip 148 lines] Plagiarizing moron. If you have nothing to say, don't. -- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) "Quis custodiet ipsos custodes?" The Net! |
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Patrick Reany wrote in message
om... Taken from: FOUNDATIONS OF PHYSICS BY ROBERT BRUCE LINDSAY, Ph.D. Associate Professor of Theoretical Physics, Brown University AND HENRY MARGENAU, Ph.D. Assistant Professor of Physics Yale University NEW YORK JOHN WILEY & SONS, Inc. LONDON: CHAPMAN & HALL, LIMITED, 1936 From the poster: Note the role that conventionalism and agreement play in the founding of a science by these authors. Why do the authors define physics as they do: the "task of physics as of all science is found in the coherent description of experience"? Do you hgave a better definition or characterization of physics? Is the notion of the "material world" really problematic? What would the realist say? What would the instrumentalist say? {snip the rest} It's all irrelevant. Science is the application of the scientific method. Nothing more or less. Anyone who wants to come up with their own, personal approach to the universe is welcome to do so. But they may not appropriate the word, 'science.' greywolf42 ubi dubium ibi libertas |
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"Ken S. Tucker" wrote in message om... (Patrick Reany) wrote in message . com... Taken from: [brevity snip, see OP's 1st post...] My definition of physics: Physics is the search for the smallest set of rules Is smallest relative? by which we can completely describe the behavior of inanimate matter Is animate matter exempt from physics? The word "behavior" covers this case. Rather than a search for "the smallest set of rules", I suggest that it is a search for sets of viable, cost-effect rules". The smallest set may be so complex or unwieldy, that the use of this set would be counter productive to individuals and society. For example if a "small set of rules" was in reality the "theory of everything", but the set was too complex, cumbersome, inefficient, etc. to be useful, physics would continue, and efforts would be made using the TOE set as a target, to come up with sub sets that with viable and cost-effective. -- Tom Potter http://tompotter.us |
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Patrick Reany:
[...] describe or explain the behavior of the material world. We cannot help feeling that this is meant to imply the existence of such a world, though what the adjective "material" here means is by no means clear. The physicist has been striving for years to attach a clear meaning to the term matter, and undoubtedly we have reason to believe that the concept means much more to us today than to the physicists of fifty years ago. However, to have a clear understanding of a physical concept like matter is not at all equivalent to the assumption that there is a "real" world behind our sense-perceptions which is responsible for the existence of matter. Allow me to mention what weinberg said in this regard at a talk of his I attended a while back. His point of view regarding a "theory of everything", was that it would not be a very satisfactory theory unless it gave one confidence that one really understood what was going on in the universe and did something more than simply produce the correct numbers. |
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Patrick Reany:
No. But the "being alive" aspect of animate matter is superfluous for two reasons in physics: The first is that when physics models animate matter, it will model it as collections of inanimate parts or systems anyway (levers, pullies, potential differences, ion transport, pressures, forces, heat flow, etc), and second, basic reasearch in physics does not require animate objects, at least it has not been the case in a long time. Not necessarily. The physics required for the condition we call "being alive" might place constraints on the variety of universes that could have been possible. The ability of the universe to support living things precludes universes which have only one or two spatial dimensions, for example. |
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#9
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"Patrick Reany" wrote in message om... Taken from: FOUNDATIONS OF PHYSICS BY ROBERT BRUCE LINDSAY, Ph.D. Associate Professor of Theoretical Physics, Brown University AND HENRY MARGENAU, Ph.D. Assistant Professor of Physics Yale University NEW YORK JOHN WILEY & SONS, Inc. LONDON: CHAPMAN & HALL, LIMITED, 1936 From the poster: Note the role that conventionalism and agreement play in the founding of a science by these authors. Why do the authors define physics as they do: the "task of physics as of all science is found in the coherent description of experience"? Do you hgave a better definition or characterization of physics? Is the notion of the "material world" really problematic? What would the realist say? What would the instrumentalist say? ------------------------------------------------------ --- p. 1 --- THE MEANING OF A PHYSICAL THEORY 1.1. The Data of Physics. Physics is concerned with a certain portion of human experience. From this experience the physicist constructs what he terms the physical world, a concept which arises from a peculiar combination of certain observed facts and the reasoning provoked by their perception. While most textbooks of physics set themselves the task of presenting to the student in the most adequate pedagogical manner the features of the physical world as they have been historically developed, it is the principal purpose of the present volume to conduct an inquiry into the logical constituents of these features, analyzing them into such elements as observed facts, definitions, postulates, and deductions. What, then, is experience, and how much of it concerns the physicist? A detailed answer to the first part of this question would lead us into the depths of philosophy, to which this book is not primarily devoted. Nevertheless, a few remarks on this point are necessary to avoid possible misconceptions. We shall at once assume the possibility of experience and knowledge as the metaphysical basis upon which any science fundamentally rests. Moreover, we shall accept the genuineness of the sense-perceptions of normal people and abstain from quarreling about the meaning of normality in this connection. Naturally, the physicist like all scientists must be forever on his guard against abnormal perceptions, but he has, we assume, objective criteria for detecting them. We must also grant the possibility of the exchange of knowledge, that is, the understanding of another's sense-perceptions and reflections in terms of one's own. A further assumption, however, must be made about experience before science as we know it becomes possible. Not only must there be agreement about it among normal people, but also it must exhibit a certain uniformity. That is, many sense-perceptions do not occur completely at random, but certain more or less well-defined groups of perceptions repeat themselves over and over again with only slight --- p. 2 --- 2 THE MEANING OF A PHYSICAL THEORY and often insignificant variations. The alternation of day and night with their attendant phenomena illustrates this point, and the reader will be able to supply other examples from all branches of science. There thus appears to be a kind of order in natural phenomena which is often expressed as the law of cause and effect: if a certain group of sense-perceptions appears a number of times associated with a second group, we expect that a repetition of the first group will always be associated with that of the second. This is not the place for a detailed discussion of the significance for physics of the assumption of uniformity in its various forms. We shall have occasion later (Chapter X) to investigate these matters more closely and are here introducing them merely as a means of initiating our discussion. Now, clearly, physics is not concerned with the whole body of human experience. How, then, are the data of physics selected? Before we come to this question, however, let us make quite plain that the task of physics as of all science is found in the coherent description of experience. Physics has nothing to say about a possible real world lying behind experience. It is extremely important to realize that, although physics rests upon the assumptions of the possibility of knowledge and the uniformity of experience, the other philosophical problems connected with realism and idealism have no significance for it. One often hears the statement that the task of physics is to describe or explain the behavior of the material world. We cannot help feeling that this is meant to imply the existence of such a world, though what the adjective "material" here means is by no means clear. The physicist has been striving for years to attach a clear meaning to the term matter, and undoubtedly we have reason to believe that the concept means much more to us today than to the physicists of fifty years ago. However, to have a clear understanding of a physical concept like matter is not at all equivalent to the assumption that there is a "real" world behind our sense-perceptions which is responsible for the existence of matter. There is perhaps no harm in such an assumption---in fact, certain minds may find that it enables them more firmly to grasp and feel confidence in physical theories; yet it must be stressed that the assumption is no necessary part of physics, and that in a logical development of the subject the safest course is to omit it entirely. It is possible, indeed, to take the view that adopting such an assumption as part of the physicist's stock-in trade involves a handicap. There is scarcely any use in believing in a real material world behind physical phenomena unless it is a permanent, unchanging affair toward the knowledge of which we progress with slow but certain steps. But our knowledge of it is based naturally --- p. 3 --- 1.1 THE DATA OF PHYSICS 3 on the prevailing physical theories. It seems as if the belief in such a world may tend to encourage too close adherence to reasonably successful physical theories with too small allowance for their necessary revision to meet the demands of new experience. Thus, the term "physical world" used in the introductory paragraph is not to be construed as being identical with real world. ----------------------------------- My definition of physics: Physics is the search for the smallest set of rules by which we can completely describe the behavior of inanimate matter under natural circumstances. Back when mechanics was thought to be the correct program to found all of physics, it made sense to think of matter as fundamental and irreducible, but since the advent of field theories this is not so meaningful, as the material particle itself can be modeled as a "localization" or accumulization of field, like the bunching up of a tablecloth. Patrick Since this post has appeared in sci.physics.relativity as well as sci.physics, I would like to endorse the emphasis the author has placed on assumption, and where it show up in Einstein's "On the Electrodynamics of Moving Bodies". quote In agreement with experience we further assume the quantity 2AB/(t'A-tA) = c, to be a universal constant... unquote If I toss a ball to you and run away, you toss it back and I catch it, then my experience is that it will take longer for you to return the ball to me than it did for me to send the ball to you. It is my further experience that the speed of the ball, relative to me, will be different to the speed of the ball relative to you in neither direction. Only if I remain at rest with respect to you can we agree on the velocities and the times of transit in each direction. Why would anyone make an assumption that the times and speeds were equal when the same situation is applied to light, since it is not in agreement with experience? It is at this juncture that a turning point is made in the history of physics. We've departed from experience, gone into the realms of assumption, and live in a mathematical world that has no correlation with Nature. If you want to *find* the smallest set of rules, it's probably best not to create them out of assumption. Human imagination knows no bounds, but Nature is there to be studied, not created from our minds. Ptolemy's epicycles worked well for 2000 years, and were hopelessly wrong, becuase he assumed the Earth was the centre of the universe. We've been making a similar mistake, based on asumption, for the last 98 years. Androcles |
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