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Cambridge University Press eBooks

Excess Baggage

James B. Hartle

Published Oct 25, 1991• 4 citations
Publisher

Abstract

QUANTUM COSMOLOGY It is an honor, of course, but also a pleasure for me to join in this celebration of Murray Gell-Mann's sixtieth birthday and to address such a distinguished audience. Murray was my teacher and more recently we have worked together in the search for a quantum framework within which to erect a fundamental description of the universe which would encompass all scales – from the microscopic scales of the elementary particle interactions to the most distant reaches of the realm of the galaxies – from the moment of the big bang to the most distant future that one can contemplate. Such a framework is needed if we accept, as we have every reason to, that at a basic level the laws of physics are quantum mechanical. Further, as I shall argue below, there are important features of our observations which require such a framework for their explanation. This application of quantum physics to the universe as a whole has come to be called the subject of quantum cosmology. The assignment of the organizers was to speak on the topic “Where are our efforts leading?” I took this as an invitation to speculate, for I think that it is characteristic of the frontier areas of science that, while we may know what direction we are headed, we seldom know where we will wind up.

DOI
10.1017/cbo9780511563980.002

Related papers

The Quantum Universe: Essays on Quantum Mechanics, Quantum Cosmology and Physics in General

James B. Hartle

Computability and physical theories / R. Geroch and J.B. Hartle -- Excess baggage -- Sources of predictability -- The no-boundary wave function of the universe -- Scientific knowledge from the perspective of quantum cosmology -- The physics of 'now' -- The quantum mechanics of closed systems -- The spacetime approach to quantum mechanics -- Quantum physics and human language -- Quantum pasts and the utility of history -- The quasiclassical realms of this quantum universe -- Living in a superposition -- The quantum mechanical arrows of time -- Why our universe is comprehensible -- Quantum cosmology : problems for the 21st century -- Anthropic reasoning and quantum cosmology -- Are we typical? / J.B. Hartle and M. Srednicki -- Science in a very large universe / M. Srednicki and J.B. Hartle -- The observer strikes back / J.B. Hartle and T. Hertog -- Quantum multiverses -- Quantum mechanics at the Planck scale -- The state of the universe -- The impact of cosmology on quantum mechanics -- Murray Gell-Mann : a short appreciation -- Working with Stephen Hawking

•Jul 13, 2020•0 citations

Excess Baggage

James B. Hartle

Many advances in physics have in common that some idea which was previously accepted as fundamental, general, and inescapable was subsequently seen to be consequent, special, and dispensable. The idea was not truly a general feature of the world, but only perceived to be general because of our special place in the universe and the limited range of our experience. It was excess baggage which had to be jettisoned to reach a more a more general perspective. This article discusses excess baggage from the perspective of quantum cosmology which aims at a theory of the universe's quantum initial state. We seek to answer the question `Which features of our current theoretical framework are fundamental and which reflect our special position in the universe or its special initial condition?' Past instances of cosmological excess baggage are reviewed such as the idea that the Earth was at the center of the universe or that the second law of thermodynamics was fundamental. Examples of excess baggage in our current understanding of quantum cosmology are the notion that measurement is central to formulating quantum mechanics, a fundamental quantum mechanical arrow of time, and the idea that a preferred time is needed to formulate quantum theory. We speculate on candidates for future excess baggage. (This article appeared in 1991 but is posted here for accessibility and possible current interest.)

•Jul 30, 2005•7 citations

Excess Baggage

James B. Hartle

Many advances in physics have in common that some idea which was previously accepted as fundamental, general, and inescapable was subsequently seen to be consequent, special, and dispensable. The idea was not truly a general feature of the world, but only perceived to be general because of our special place in the universe and the limited range of our experience. It was excess baggage which had to be jettisoned to reach a more a more general perspective. This article discusses excess baggage from the perspective of quantum cosmology which aims at a theory of the universe's quantum initial state. We seek to answer the question `Which features of our current theoretical framework are fundamental and which reflect our special position in the universe or its special initial condition?' Past instances of cosmological excess baggage are reviewed such as the idea that the Earth was at the center of the universe or that the second law of thermodynamics was fundamental. Examples of excess baggage in our current understanding of quantum cosmology are the notion that measurement is central to formulating quantum mechanics, a fundamental quantum mechanical arrow of time, and the idea that a preferred time is needed to formulate quantum theory. We speculate on candidates for future excess baggage. (This article appeared in 1991 but is posted here for accessibility and possible current interest.)

arXiv:gr-qc/0508001•Jul 30, 2005•0 citations

In the Beginning Was Quantum Mechanics

Dietrick E. Thomsen

In principio erat verbum. It seems appropriate to add the first few words of St. John's gospel to the Latin quotations that were bandied about at the beginning of the recent Workshop on Cosmology, which was held at the Fermi National Accelerator Laboratory in Batavia, Ill. This outburst of Latinity and classical scholarship, which even included a dispute over whether the word apparatus belongs to the second or the fifth declension, seemed an appropriate beginning for a conference on a subject the origins of the universe that has fascinated scholars ever since classical times. In the beginning was the word, en arche hen ho logos. One of the meanings of logos in this context is a word descriptive of the basic structure of the universe and, more than descriptive, a dynamical word that outlines and perhaps even determines the course of the history that follows the beginning. From the philosophers of ancient Hellas to the professors of physics in modern universities, most have expected that this word would be mathematical. It is the last generation or two that has expected it to be quantum mechanical. Quantum mechanics has to describe everything, said Murray Gell-Mann of Caltech in Pasadena in the opening talk of the workshop. And it became clear that by everything he meant the work of historians and crime detectives and the songs of birds as well as the motions of galaxies. But he added: questions are all murky and border on the philosophical. The main reason for the dominance of quantum mechanics was cited by James Hartle of the University of California at Santa Barbara: laws of physics are quantum mechanical; quantum cosmology is the proper framework. Nevertheless, the large objects that dominate the universe as we now see it operate according to classical mechanics. The serious problem for all of physics, and for quantum cosmology in particular, is to find some kind of linkage by which classical physics can be generated out of quantum mechanics. A similar question occurs historically: If we trace the expansion of the universe backwards we eventually come to a point in history when the universe was so small that it had to behave as a whole as a quantum mechanical system. Figuring out how the present came out of the past is the problem.

Science News•May 30, 1987•0 citations

“Is Quantum Mechanics for the Birds?”

V. L. Telegdi

I would like to correct a misrepresentation made by several of the preceding speakers. We are not celebrating the sixtieth anniversary of Murray's birthday. We are celebrating the sixtieth anniversary of his conception. His actual birthday is in September. We are, of course, celebrating Murray Gell–Mann, whom I've known now since 1951. We joined the University of Chicago the same year, a few months apart. And before I go into the more scientific part of my lecture, I think you might be interested in the origin of the name “Murray.” Presumably it was, like some other first names, derived from a surname. And these, in turn, often come from geographical names, in the present case, from a Scottish province, “Muraih.” Already in 1203 we find a William de Moravia, and in 1317 an Orland de Morris, and in 1327, an Andrew Muraih. [This does not prove the point, because these family names could well have come from “Murie,” the Middle English form of Merry.] As a first name, it has also been surmised, as I see from a book by Partridge, Name This Child , that “Murray” comes from “Murrey” a word for dark red or eggplant colored, an adjective which in turn presumably comes from mulberry, in turn connected to maroon. Which brings us back to Murray's favorite color of corduroy jackets at the University of Chicago. Now having explained the word Murray, I cannot refrain from giving you the origin of the name Gell–Mann.

Cambridge University Press eBooks•Oct 25, 1991•0 citations

A general framework for cosmological quantum theory

Chris J. Clarke

Reports on Mathematical Physics•Jun 1, 1978•1 citation
QUANTUM COSMOLOGY It is an honor, of course, but also a pleasure for me to join in this celebration of Murray Gell-Mann's sixtieth birthday and to address such a distinguished audience. Murray was my teacher and more recently we have worked together in the search for a quantum framework within which to erect a fundamental description of the universe which would encompass all scales – from the microscopic scales of the elementary particle interactions to the most distant reaches of the realm of the galaxies – from the moment of the big bang to the most distant future that one can contemplate. Such a framework is needed if we accept, as we have every reason to, that at a basic level the laws of physics are quantum mechanical. Further, as I shall argue below, there are important features of our observations which require such a framework for their explanation. This application of quantum physics to the universe as a whole has come to be called the subject of quantum cosmology. The assignment of the organizers was to speak on the topic “Where are our efforts leading?” I took this as an invitation to speculate, for I think that it is characteristic of the frontier areas of science that, while we may know what direction we are headed, we seldom know where we will wind up.
Computability and physical theories / R. Geroch and J.B. Hartle -- Excess baggage -- Sources of predictability -- The no-boundary wave function of the universe -- Scientific knowledge from the perspective of quantum cosmology -- The physics of 'now' -- The quantum mechanics of closed systems -- The spacetime approach to quantum mechanics -- Quantum physics and human language -- Quantum pasts and the utility of history -- The quasiclassical realms of this quantum universe -- Living in a superposition -- The quantum mechanical arrows of time -- Why our universe is comprehensible -- Quantum cosmology : problems for the 21st century -- Anthropic reasoning and quantum cosmology -- Are we typical? / J.B. Hartle and M. Srednicki -- Science in a very large universe / M. Srednicki and J.B. Hartle -- The observer strikes back / J.B. Hartle and T. Hertog -- Quantum multiverses -- Quantum mechanics at the Planck scale -- The state of the universe -- The impact of cosmology on quantum mechanics -- Murray Gell-Mann : a short appreciation -- Working with Stephen Hawking
Many advances in physics have in common that some idea which was previously accepted as fundamental, general, and inescapable was subsequently seen to be consequent, special, and dispensable. The idea was not truly a general feature of the world, but only perceived to be general because of our special place in the universe and the limited range of our experience. It was excess baggage which had to be jettisoned to reach a more a more general perspective. This article discusses excess baggage from the perspective of quantum cosmology which aims at a theory of the universe's quantum initial state. We seek to answer the question `Which features of our current theoretical framework are fundamental and which reflect our special position in the universe or its special initial condition?' Past instances of cosmological excess baggage are reviewed such as the idea that the Earth was at the center of the universe or that the second law of thermodynamics was fundamental. Examples of excess baggage in our current understanding of quantum cosmology are the notion that measurement is central to formulating quantum mechanics, a fundamental quantum mechanical arrow of time, and the idea that a preferred time is needed to formulate quantum theory. We speculate on candidates for future excess baggage. (This article appeared in 1991 but is posted here for accessibility and possible current interest.)
Many advances in physics have in common that some idea which was previously accepted as fundamental, general, and inescapable was subsequently seen to be consequent, special, and dispensable. The idea was not truly a general feature of the world, but only perceived to be general because of our special place in the universe and the limited range of our experience. It was excess baggage which had to be jettisoned to reach a more a more general perspective. This article discusses excess baggage from the perspective of quantum cosmology which aims at a theory of the universe's quantum initial state. We seek to answer the question `Which features of our current theoretical framework are fundamental and which reflect our special position in the universe or its special initial condition?' Past instances of cosmological excess baggage are reviewed such as the idea that the Earth was at the center of the universe or that the second law of thermodynamics was fundamental. Examples of excess baggage in our current understanding of quantum cosmology are the notion that measurement is central to formulating quantum mechanics, a fundamental quantum mechanical arrow of time, and the idea that a preferred time is needed to formulate quantum theory. We speculate on candidates for future excess baggage. (This article appeared in 1991 but is posted here for accessibility and possible current interest.)
In principio erat verbum. It seems appropriate to add the first few words of St. John's gospel to the Latin quotations that were bandied about at the beginning of the recent Workshop on Cosmology, which was held at the Fermi National Accelerator Laboratory in Batavia, Ill. This outburst of Latinity and classical scholarship, which even included a dispute over whether the word apparatus belongs to the second or the fifth declension, seemed an appropriate beginning for a conference on a subject the origins of the universe that has fascinated scholars ever since classical times. In the beginning was the word, en arche hen ho logos. One of the meanings of logos in this context is a word descriptive of the basic structure of the universe and, more than descriptive, a dynamical word that outlines and perhaps even determines the course of the history that follows the beginning. From the philosophers of ancient Hellas to the professors of physics in modern universities, most have expected that this word would be mathematical. It is the last generation or two that has expected it to be quantum mechanical. Quantum mechanics has to describe everything, said Murray Gell-Mann of Caltech in Pasadena in the opening talk of the workshop. And it became clear that by everything he meant the work of historians and crime detectives and the songs of birds as well as the motions of galaxies. But he added: questions are all murky and border on the philosophical. The main reason for the dominance of quantum mechanics was cited by James Hartle of the University of California at Santa Barbara: laws of physics are quantum mechanical; quantum cosmology is the proper framework. Nevertheless, the large objects that dominate the universe as we now see it operate according to classical mechanics. The serious problem for all of physics, and for quantum cosmology in particular, is to find some kind of linkage by which classical physics can be generated out of quantum mechanics. A similar question occurs historically: If we trace the expansion of the universe backwards we eventually come to a point in history when the universe was so small that it had to behave as a whole as a quantum mechanical system. Figuring out how the present came out of the past is the problem.
I would like to correct a misrepresentation made by several of the preceding speakers. We are not celebrating the sixtieth anniversary of Murray's birthday. We are celebrating the sixtieth anniversary of his conception. His actual birthday is in September. We are, of course, celebrating Murray Gell–Mann, whom I've known now since 1951. We joined the University of Chicago the same year, a few months apart. And before I go into the more scientific part of my lecture, I think you might be interested in the origin of the name “Murray.” Presumably it was, like some other first names, derived from a surname. And these, in turn, often come from geographical names, in the present case, from a Scottish province, “Muraih.” Already in 1203 we find a William de Moravia, and in 1317 an Orland de Morris, and in 1327, an Andrew Muraih. [This does not prove the point, because these family names could well have come from “Murie,” the Middle English form of Merry.] As a first name, it has also been surmised, as I see from a book by Partridge, Name This Child , that “Murray” comes from “Murrey” a word for dark red or eggplant colored, an adjective which in turn presumably comes from mulberry, in turn connected to maroon. Which brings us back to Murray's favorite color of corduroy jackets at the University of Chicago. Now having explained the word Murray, I cannot refrain from giving you the origin of the name Gell–Mann.