The Anthropic Cosmological Principle (Oxford Paperbacks) Revised ed. Edition
by John D. Barrow (Author), Frank J. Tipler (Author), John A. Wheeler (Foreword)
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Editorial Reviews
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`an engaging book ... practically a universal education in both the history of modern science and the history of the Universe ... will be much quoted, much debated and much praised' Nature
`a feast: the kind of book which tells you everything you want to know about everything' The Economist
`I was infuriated by it, disagreed with it and loved reading it.' Timothy Ferris, New York Times Book Review
`in the speculative and intellectual richness of its pages, this book is probably unsurpassed' Peter Atkins
`a masterly exposition of what seems bound to become one of the most important developments to have taken place in physical science' TLS
`Intriguing analysis of new scientific thinking.' Sydney Times
`unique and wide-ranging book ... The reader is taken on an eclectic study of many scientific disciplines and is presented with a revealing picture of the structure of the physical world solely in terms of its invariant constants. There are also fascinating chapters on the definition and nature of life, the search for extra-terrestrial intelligence and the interpretation of quantum theory in relation to the existence of observers.' Europe & Astronomy 1992
`If you get a kick out of cosmic coincidences The Anthropic Cosmological Principle ... is definitely for you. The "anthropic" idea, which is that our very existence may explain why the Universe is the way it is, is an extraordinary one. So too is Barrow and Tipler's account.' New Scientist
From the Back Cover
In their classic work, John Barrow and Frank Tipler examine the question of mankind's place in the Universe, taking the reader on a tour of many scientific disciplines and offering fascinating insights into issues such as the nature of life, the search for extraterrestrial intelligence, and the history and fate of our universe.
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Product details
Publisher : Oxford University Press; Revised ed. edition (August 25, 1988)
Language : English
Paperback : 738 pages
Frank J. Tipler
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John D. Barrow
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Top reviews from the United States
jdvb books
5.0 out of 5 stars Well worth the time.Reviewed in the United States on September 5, 2018
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Any college graduate should know there would be no life let alone intelligent life on earth if we were not located at a specific distance from a G2 star on a planet well endowed with water and the basic chemicals and timescale required for the evolution of carbon based life forms. The reason I bought this text was from several references with cited it as listing a host of other improbable cofactors related to the formation, physics, chemical properties and time lapse of the universe required for the evolution of mankind to a point that we can even attempt to understand the universe and the world in which we live. Those factors are very well elaborated and described. We are indeed fortunate to be alive.
This was a long difficult read for me requiring a great deal of thought and reference work. Some sections related to physics and math were simply beyond my understanding in spite of a strong postgraduate science base and attempts to keep abreast in advances in science. I could work through much of the math but quantum physics and cosmology have advanced well beyond my education and a fair amount of subsequent readings in these fields. This was the rare book I enjoyed in spite of having to pass over a few chapters and sections. My interest and knowledge in biology and chemistry made these chapters very rewarding and informative pulling together many issues I had never before considered. I was one of those rare college students who was fascinated by biochemistry and those sections alone were well worth the read. Frankly the extensive side work required to understand many of the arguments was also a positive. The knowledge base of the authors not only in the various science disciplines but also in history and philosophy is extraordinary. Recognize a great deal of advancement in science has occurred since the first edition of the book in 1986.
While I hesitated to share this book with my son who majored in the arts, philosophy and theology due to his lack of interest and education in science much beyond Newtonian physics and Mendel's genetics I will do so because an understanding of the limits of our personal knowledge base is critical as has been so throughly demonstrated since the 2016 elections in the USA.
Not sure I share the optimism of the authors with the advancement and potential of the human species, critical factors in accepting the conclusions of the authors. Nevertheless, anyone who fails to read the book based on their preconceived ideas of design, lack of design or purpose of the universe will be missing a major intellectual work of value.
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Rich
5.0 out of 5 stars Review: The Anthropic Cosmological Principle (John Barrow and Frank Tipler)Reviewed in the United States on September 27, 2021
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This book is about the Anthropic Cosmological Principle (ACP) and its shadow cousin, Intelligent Design (ID) and how the universe evolved with what seems to be intent and purpose in creating the perfect conditions for life to emerge on a universal scale. The ACP asserts that the universe seems particularly suited to bring about and support human life (weak anthropic principle), whereas the ID argument says that life, or the universe, cannot have arisen by chance and was designed and created by some super intelligent entity. There is much discourse surrounding this dual in the text along with various theme variations as the issues evolved throughout history. The implications of the multi-verse and quantum mechanics are also included in this history. Metaphysical and philosophical discussions include, the final cause, spiritualism and materialism, the multi-verse, quantum mechanics influences, theism, cosmology, and much more are among the plethora of topics included.
There are three fundamental ACPs discussions in the book including the Strong Anthropic Principle, the Weak Anthropic Principle, and the Final Cosmological Principle. The case for each is discussed along with criticism on the merits of each.
There are 25 fundamental physical constants in the universe whose values coincidently are exactly fine tuned to make life possible or even inevitable in the universe (gravitational constant, strong nuclear force constant, the polarity of water molecule, et al). The probability of such a coincidence is extraordinarily small; how or why did this happen? If any of these parameters were different in their attributes by even one or two percent, life on earth may not have been possible. It is as though the universe was providing a pathway for life and consciousness with intent and purpose using the big-bang fall-out.
This book is an intense read and requires a good background in the physical sciences and mathematics. Many of the chapters contain no mathematics, others require calculus. The intensely mathematical chapters can be skimmed without loss of fundamental ideas. The material is really good reading and well worth the effort.
Rich
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xingren
5.0 out of 5 stars Life, the Universe, and EverythingReviewed in the United States on September 25, 2019
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I had a copy of an early edition of this book, but it was borrowed by a friend who promptly moved to another province... Now I've refilled that gap on my shelf with an uptodate edition of this comprehensive and detailed thesis. The footnotes at the end of each chapter would themselves fill a small library. Don't worry about the little bits of math, most of the text is easy reading. Recommended for anyone looking for an overview of cosmogony and our part in it.
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Richard Ventura
5.0 out of 5 stars A design of super intelligenceReviewed in the United States on October 31, 2019
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Excellent work but very technical. It is excellent in describing the incredible high precision fine tuning of the Universe showing that only a super intelligent genius I.e., God, could have designed it for life! It helps to have a knowledge of science to fully appreciate it!
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Phoober
5.0 out of 5 stars Dense - take your time!Reviewed in the United Kingdom on October 6, 2017
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Want a full on brain workout - read this. If you like interdisciplinary reads, this is definitely for you, but it needs reading slowly and over a period of months (may be even years!) It's just too dense to sit down and take in over a nice cup of morning coffee!
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Mr Paul Landman
5.0 out of 5 stars One of the best books I've ever hadReviewed in the United Kingdom on April 4, 2020
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This book will blow your mind! Recommended for those looking for enlightenment!
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Adam Southworth
5.0 out of 5 stars Five StarsReviewed in the United Kingdom on November 29, 2017
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Great product, swift delivery. Thanks.
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Joe
5.0 out of 5 stars Great book, but a bit musty.Reviewed in the United Kingdom on December 30, 2020
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Heavy reading. Enjoyable, but it was a struggle to finish. That said, excellently well written. The best books require a ton of thinking and that’s one of them.
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Nicko
5.0 out of 5 stars Very fascinating but quite a lot of math in it ...Reviewed in the United Kingdom on March 2, 2016
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Very fascinating but quite a lot of math in it. I think the chapter about the existence of extraterristials is wrong as it rests on some rather questionable assumptions. An important book.
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==
If you're into stuff like this, you can read the full review.
Superstitionists: "The Anthropic Cosmological Principle" by John D. Barrow, Frank J. Tipler
This is a frankly stupid argument and it surprises me that in the course of more than 25 years, otherwise highly intelligent people (scientists, I mean, superstitionists, not so much) still bother to engage in it.
So far as the apparent fine-tuning of the universe for our kind of life is concerned:
1. It does not matter whether there is an infinity of parallel universes; or 24; or three; or just this one.
2. It does not matter whether there have been millions of earlier Big Bangs, or just 42; or five; or just this one. (less)
Superstitionists: "The Anthropic Cosmological Principle" by John D. Barrow, Frank J. Tipler
This is a frankly stupid argument and it surprises me that in the course of more than 25 years, otherwise highly intelligent people (scientists, I mean, superstitionists, not so much) still bother to engage in it.
So far as the apparent fine-tuning of the universe for our kind of life is concerned:
1. It does not matter whether there is an infinity of parallel universes; or 24; or three; or just this one.
2. It does not matter whether there have been millions of earlier Big Bangs, or just 42; or five; or just this one. (less)
Dec 26, 2010Ushan rated it really liked it
This review was not written by a one-year-old human child because a one-year-old human child's mind is too simple to write this review. Douglas Hofstadter used to be fond of this kind of meaningful self-referential statements. This review was also not written during the first million years after the Big Bang, because any being that could conceivably write this review would be composed of solid and liquid matter, and during the first million years after the Big Bang, all matter in the Universe was in the plasma state. This review could not be written if the Milky Way had been the only galaxy in the Universe, since a Universe with only the Milky Way's worth of matter would stop expanding and start collapsing within a month of the Big Bang. The authors quote the eighth book of Milton's Paradise Lost, where Adam asks an angel, why the Universe is so large; the angel replies, "That Man may know he dwells not in his own - An edifice too large for him to fill, Lodged in a small partition, and the rest Ordained for uses to his Lord best known." The correct answer is that if the Universe were smaller, Adam himself would not exist. In fact, physics and cosmology tell us that both the constants of nature and the initial cosmological parameters required for the evolution of any thinking being have to be very precisely the ones we observe: for helium inside stars to be transformed into carbon, a resonant state of carbon-12 must have a mass just above the combined mass of beryllium-8 and helium-4, and for it not to be immediately transformed into oxygen, a resonant state of oxygen-16 must have a mass just below the combined mass of carbon-12 and helium-4. Apparently biochemistry requires carbon and oxygen; ammonia is sufficiently unlike water and silicon is sufficiently unlike carbon to preclude the development of silicon-based instead of carbon-based life, or ammonia-based instead of water-based life. This of course has been controversial ever since this book was published; arxiv.org has a paper claiming that the Universe without the weak interaction could still support life and another that criticizes it. Nobody knows, why the constants of nature have the values they do, whether or not they or the initial cosmological parameters could have been different.
Although this book gives a long history of philosophical and theological arguments about the Universe being designed for humans, it does not mention my favorite, from Tom Paine's The Age of Reason: God created the six planets so that humans (as well as the inhabitants of the other planets) could discover the Law of Universal Gravitation, and consequently develop modern science and technology. (less)
Although this book gives a long history of philosophical and theological arguments about the Universe being designed for humans, it does not mention my favorite, from Tom Paine's The Age of Reason: God created the six planets so that humans (as well as the inhabitants of the other planets) could discover the Law of Universal Gravitation, and consequently develop modern science and technology. (less)
Anthropic principle; is it intelligent design or fine tuning of physical constants or mere coincidences?
The anthropic coincidences are connections between physical constants that seem to be necessary for the existence of life in the universe and the physical reality we observe. Physical reality defined from the physical and scientific data is limited because it is not only limited by the narrow focus of our instrument and the boundaries of physical laws but also by the observer/experimenter's input in data collection process (observation selection effect.) The anthropic reasoning seeks to explain this physical reality from a philosophical standpoint. There are over 30 anthropic principles and they are tautological (circular reasoning), and hence indisputable, which makes many scientists skeptical about this idea. However, in multiverse concept, where space and time are infinite, then it is possible that fundamental physical constants may have a broad distribution in billions of universes, and in a selected universe it is quite likely that these constant may be fine tuned so that carbon based life (intelligent observers) may evolve. Such an idea avoids the universal selection of constants.
The authors bring a unique combination of skills from their specialized field of study and make every effort to discuss every aspect of anthropic principle, the best thoughts of past and present to make a comprehensive discussion in a meticulous manner. Examples include; does nature limit itself to three spatial and one time dimension at the most fundamental level (chapter 4); the anthropic relationship with cosmological factors (chapter 6); quantum physics and anthropic principle (chapter 7); and chapter 8 on the discussion of biological and statistical considerations in anthropic reasoning. This is also a good book to read about an introduction to quantum physics and cosmology.
The book may be summarized as follows: The idea of anthropic reasoning became apparent when the values of physical constants were considered. For example, the ratio of electromagnetic force to the gravitational force between two electrons is of the order of 10e(39). This is puzzling since pure numbers not associated with any measuring units must be close to unity when describing physical properties. Physicist Herman Weyl first observed this phenomenon and suggested that there may be a universal selection principle in operation. This large disparity is essential for life because if they were of comparable strengths, then the stars would collapse long before life had time to evolve.
The Brandon carter's weak anthropic principle (WAP) states that our location in universe is privileged to the extent of being compatible with our existence as observers, and strong anthropic principle (SAP) states that the universe (and its fundamental constants) must be such that it creates observers. Most constants such as gravitational constants, the speed of light (may be derived form Maxwell's equations), the electric charge, the mass of the electron, and Planck's constants are arbitrary, but the values of these constants make a great deal of difference between the selection of carbon based life (observers) and a universe with no life. For example, the gravitational constant must have the "correct" value to balance the repulsive and attractive forces in the interior of a star so that planetary system could evolve followed by carbon based life. The strong force coupling constants must have the "correct" value so that it holds together the nucleus of an atom together in a relatively stable form. The electromagnetic coupling constants with its "correct" value also hold the electrons and the nucleus in a stable form so that atoms, molecules and complex structures can evolve. If these constants deviate by a narrow range of 1 to 5 percent, atomic configurations wouldn't have existed, and intelligent life would be impossible.
The quantum reality interpreted by the many worlds hypothesis where every possible realization of position and energy of every particle exists. This interpretation resolves the problem of anthropic principle since we live in one of the many universes which support life. The anthropic coincidences are not coincidences after all, they are just one possibility of billions of possibilities that exists parallel to our universe. The cosmic inflationary theory also resolves the problem of anthropic principle in a similar fashion. The inflation at the symmetry breaking point of Grand Unified Theory resulted in enormous amount of energy that expanded spacetime at enormous heights of the order of 10e(54), but the matter moved by the limitations of special relativity. Thus our universe is like a bubble in an infinite number of universes that were formed. Our universe had the appropriate physical constants that lead to the evolution of intelligent life and this was not predetermined or required. Another early subscriber to an ensemble picture of multiverse was physicist Fred Hoyle. His interest in the many possible worlds of the anthropic principle was provoked by his discovery of a remarkable series of coincidences concerning the nuclear resonance levels of biological elements. Just as the electrons of an atom can be considered to reside in a variety of states according to their energy levels so it is with nucleons. Neutrons and protons have analogous spectrum of nuclear energy levels. If nucleons undergo a transition from a high to a low energy state then energy is emitted; conversely, the addition of radiant energy can effect an upward translation between nuclear levels. This nuclear chemistry is a crucial factor in the chain of nuclear reactions that power the stars. In chapter 4 the authors discuss how the resonance energy levels of carbon, beryllium and oxygen are located at the "correct" energy states so that carbon and oxygen (building blocks of life) are formed in nuclear reactions in significant proportions inside the stars.
In conclusion, the constructs of the key features of the natural world is deduced from the knowledge of a few constants of nature. The sizes of atoms, people, and planets are not accidental nor are they the inevitable result of natural selection. Rather, they are consequences of inevitable equilibrium states between competing natural forces of attraction and repulsion.
(less)
The anthropic coincidences are connections between physical constants that seem to be necessary for the existence of life in the universe and the physical reality we observe. Physical reality defined from the physical and scientific data is limited because it is not only limited by the narrow focus of our instrument and the boundaries of physical laws but also by the observer/experimenter's input in data collection process (observation selection effect.) The anthropic reasoning seeks to explain this physical reality from a philosophical standpoint. There are over 30 anthropic principles and they are tautological (circular reasoning), and hence indisputable, which makes many scientists skeptical about this idea. However, in multiverse concept, where space and time are infinite, then it is possible that fundamental physical constants may have a broad distribution in billions of universes, and in a selected universe it is quite likely that these constant may be fine tuned so that carbon based life (intelligent observers) may evolve. Such an idea avoids the universal selection of constants.
The authors bring a unique combination of skills from their specialized field of study and make every effort to discuss every aspect of anthropic principle, the best thoughts of past and present to make a comprehensive discussion in a meticulous manner. Examples include; does nature limit itself to three spatial and one time dimension at the most fundamental level (chapter 4); the anthropic relationship with cosmological factors (chapter 6); quantum physics and anthropic principle (chapter 7); and chapter 8 on the discussion of biological and statistical considerations in anthropic reasoning. This is also a good book to read about an introduction to quantum physics and cosmology.
The book may be summarized as follows: The idea of anthropic reasoning became apparent when the values of physical constants were considered. For example, the ratio of electromagnetic force to the gravitational force between two electrons is of the order of 10e(39). This is puzzling since pure numbers not associated with any measuring units must be close to unity when describing physical properties. Physicist Herman Weyl first observed this phenomenon and suggested that there may be a universal selection principle in operation. This large disparity is essential for life because if they were of comparable strengths, then the stars would collapse long before life had time to evolve.
The Brandon carter's weak anthropic principle (WAP) states that our location in universe is privileged to the extent of being compatible with our existence as observers, and strong anthropic principle (SAP) states that the universe (and its fundamental constants) must be such that it creates observers. Most constants such as gravitational constants, the speed of light (may be derived form Maxwell's equations), the electric charge, the mass of the electron, and Planck's constants are arbitrary, but the values of these constants make a great deal of difference between the selection of carbon based life (observers) and a universe with no life. For example, the gravitational constant must have the "correct" value to balance the repulsive and attractive forces in the interior of a star so that planetary system could evolve followed by carbon based life. The strong force coupling constants must have the "correct" value so that it holds together the nucleus of an atom together in a relatively stable form. The electromagnetic coupling constants with its "correct" value also hold the electrons and the nucleus in a stable form so that atoms, molecules and complex structures can evolve. If these constants deviate by a narrow range of 1 to 5 percent, atomic configurations wouldn't have existed, and intelligent life would be impossible.
The quantum reality interpreted by the many worlds hypothesis where every possible realization of position and energy of every particle exists. This interpretation resolves the problem of anthropic principle since we live in one of the many universes which support life. The anthropic coincidences are not coincidences after all, they are just one possibility of billions of possibilities that exists parallel to our universe. The cosmic inflationary theory also resolves the problem of anthropic principle in a similar fashion. The inflation at the symmetry breaking point of Grand Unified Theory resulted in enormous amount of energy that expanded spacetime at enormous heights of the order of 10e(54), but the matter moved by the limitations of special relativity. Thus our universe is like a bubble in an infinite number of universes that were formed. Our universe had the appropriate physical constants that lead to the evolution of intelligent life and this was not predetermined or required. Another early subscriber to an ensemble picture of multiverse was physicist Fred Hoyle. His interest in the many possible worlds of the anthropic principle was provoked by his discovery of a remarkable series of coincidences concerning the nuclear resonance levels of biological elements. Just as the electrons of an atom can be considered to reside in a variety of states according to their energy levels so it is with nucleons. Neutrons and protons have analogous spectrum of nuclear energy levels. If nucleons undergo a transition from a high to a low energy state then energy is emitted; conversely, the addition of radiant energy can effect an upward translation between nuclear levels. This nuclear chemistry is a crucial factor in the chain of nuclear reactions that power the stars. In chapter 4 the authors discuss how the resonance energy levels of carbon, beryllium and oxygen are located at the "correct" energy states so that carbon and oxygen (building blocks of life) are formed in nuclear reactions in significant proportions inside the stars.
In conclusion, the constructs of the key features of the natural world is deduced from the knowledge of a few constants of nature. The sizes of atoms, people, and planets are not accidental nor are they the inevitable result of natural selection. Rather, they are consequences of inevitable equilibrium states between competing natural forces of attraction and repulsion.
(less)
Jan 07, 2019Mientras Leo rated it liked it
No ha sido la lectura que yo esperaba, la verdad.
Oct 03, 2013Alex Shrugged rated it it was amazing
Shelves: reviewed-books, astrophysics, astronomy, physics, history, science
I own the paperback version of this book and it's fascinating. It's also a lot of physics but the first four chapters are within the ability of any high school graduate because the chapters cover the history of design theories.
Scientists (and high school science teachers) generally don't like design theories because they are simple, intuitive and appealing to the average person. Refuting a design theory (and they can be refuted) takes time, some background material and the results are not very satisfying and soon forgotten.
In order to understand the Anthropic Cosmological Principle takes some background material in the history of design arguments so reading the first four chapters would be worth anyone's time.
There are mathematical formulas in the book but for the first four chapters you can skip these with no problem whatsoever. If you decide to go on, intrepid fellow, I highly recommend the discussion on Von Neumann Probes. It has convinced me that we are alone... at least within this galaxy. Otherwise we would see evidence of a visit from such a probe.
Update (2021-Feb-17): As I recall, this is my second full reading of the book. My other readings have been confined to the first 4 chapters. I confess that I lack the background to understand all of it, but I do understand a lot of it, and it has been very helpful to me. (less)
Scientists (and high school science teachers) generally don't like design theories because they are simple, intuitive and appealing to the average person. Refuting a design theory (and they can be refuted) takes time, some background material and the results are not very satisfying and soon forgotten.
In order to understand the Anthropic Cosmological Principle takes some background material in the history of design arguments so reading the first four chapters would be worth anyone's time.
There are mathematical formulas in the book but for the first four chapters you can skip these with no problem whatsoever. If you decide to go on, intrepid fellow, I highly recommend the discussion on Von Neumann Probes. It has convinced me that we are alone... at least within this galaxy. Otherwise we would see evidence of a visit from such a probe.
Update (2021-Feb-17): As I recall, this is my second full reading of the book. My other readings have been confined to the first 4 chapters. I confess that I lack the background to understand all of it, but I do understand a lot of it, and it has been very helpful to me. (less)
I hardly know how to review this book. It was fascinating at times, very philosophical, but could also read like a textbook that was impossible to understand without a PhD in physics (I have a Masters in physics, but apparently, that wasn't enough!). Despite the far too technical parts, it was an excellent overview of the anthropic cosmological principle, how the universe is "suited" for life to evolve, which we can either take as an obvious statement (if it wasn't, we wouldn't be here to observe it, so it has to be this way!) or something more profound (that it was meant to be this way). The first few chapters on the philosophy and history were the best, in my opinion, and not hard to understand. I read most of the book, but skipped over some sections near the end because they were too technical, but overall, an intriguing read. (less)
Dec 03, 2008Alex is currently reading it
Mind meltingly scientific and bigger picture generalizations at the same time.
Mar 25, 2021P Mc rated it it was amazing
Shelves: 1981-to-2008, british-isles, philosophy, science, usa-and-canada
I read this in 1988 after being kicked out of Fordham and taking a Calculus Class and Chemistry Class at Fairfield (not eventually getting a bachelor's degree was not an option in my family's SES no matter how irresponsible I was.) I was strolling through Nyselius library looking for books unrelated to my studies, I have a penchant for being studious in subjects that won't help my academics I ran across this one. It was written by Tipler and Barrow about the Teleological end of the Universe and the possibility of using the big crunch (before findings in 1998 made the point moot no big crunch in the cards now) to make a superintelligence that would through computational simulation in that ever-energetic in an asymptotic speedup to infinity of computation as the crunch takes place this Omega point intelligence will resurrect the dead and have god-like powers. A physicist's eschaton. Tipler wrote a more popular book on this in the 1990s called "The Physics of Immortality" he needless to say later on got a little caught up on the Christian parallels and probably because he was raised in an evangelical household found himself back in the fold if a little flakier in both his physics and religion. Still, the idea of a day of resurrection still is a yearning put in me at Catholic school which I haven't completely escaped. The book also talks about anthropic reasoning something all the rage these days and Barrow and Tipler were early adopters. Worth a look at this oldie but goodie. (less) (less)
Sep 10, 2008David rated it it was amazing
Although published in 1988, this is still the authoritative source on the intriguing question of whether (or why) the universe is "special" for us, in the sense of the "anthropic principle" -- i.e., we should not be surprised that the universe (and our corner of it) has the properties it does, because otherwise we would not be around to pose the question... (less)
May 19, 2012Simon Mcleish rated it really liked it
Originally published on my blog here in October 1999.
It may seem that there is not very much to be said about the anthropic principle, that it is an interesting sideline in the philosophy of science which may have a minor role in explaining why the universe is the way it is. To Barrow and Tipler, it has formed the peg around which a seven hundred page book can be written, one which takes the reader on a survey of cosmology, theology, the future of the human race, and the existence of extra-terrestrial intelligence. It is a fascinating book, occasionally rather on the mathematical side for a popular science book.
The anthropic principle, as discussed by Barrow and Tipler, comes in three varieties, with a "Final" form as well as the more familiar "Weak" and "Strong" versions. The Weak Anthropic Principle is hardly contentious. It merely says that the existence of carbon based life is an observed fact, so that the universe must have properties which make such life a possibility. Barrow and Tipler make as strong a case as is possible for the explanatory power of this idea, but I still feel that it is limited. It may explain, for example, that the universe has to be large even if the Earth is the only planet containing life (to have expanded for long enough for galaxies to form and supernovae to occur to create some of the elements we require), but not why the universe happens to be this large. All the principle states is that if it weren't, we wouldn't be here to observe the fact. However, most of what can be inferred from it doesn't actually require the presence of life; the example I've referred to could be deduced just as logically from the existence of uranium. (Life is a sufficiently complex phenomenon that it requires a large collection of such pre-conditions, so the anthropic principle is a convenient summary of many similar explanations.) It also involves the deduction of causes from effects, and that is something which requires a great deal of care, to say the least.
The stronger versions of the anthropic principle are far more contentious, and more closely related to the design arguments used to "prove" the existence of God from the appearance of design in the universe. (These arguments are summarised in an excellent historical overview which forms the first chapter of the book.) The standard strong principle says that life must evolve at some point in the history of the universe, rather than that it just has evolved. As Barrow and Tipler point out, this means that life can be said to be part of the "purpose" of the universe in some way, and this doesn't make much sense without the deduction that life must at some point have a measurable effect on the whole cosmos. This point leads into a lengthy discussion of just what this effect could possibly be, which is fascinating but extremely speculative. The first point made is that it is very difficult to imagine any way in which a species confined to a single star system could affect the universe. So interstellar travel is a necessary development, and that requires intelligence. This is the motivation behind the authors' formulation of what they call the Final Anthropic Principle, which states that intelligence must at some point arise and never die out.
The discussion of how interstellar (and, indeed, intergalactic) travel could be developed is fascinating and seems convincingly feasible. Their ideas are based on the theoretical von Neumann machine, which is basically a machine which can create replicas of itself. A von Neumann machine could be made a space probe that seeks out a star likely to have the resources to enable replication (using a strategy based on analysis of the Polynesian colonisation of the Pacific islands), and then copies itself. Given sufficient processing power to be considered intelligent and a sufficient density of planetary systems - considered likely in current astronomy - this would amount to colonisation of the galaxy by intelligent systems over a period of several thousand years.
In fact, these arguments are sufficiently convincing that they are used to support the idea that there is no more advanced race of beings in the galaxy than humanity, because we should now have been contacted by probes of this sort. (Even if they did not want to directly contact other forms of life, the action of such a probe on reaching the solar system would probably be detectable.) The idea that we are alone in the galaxy, however, contradicts the equally convincing "Copernican Principle", that there should not be anything particularly special about the Earth - we are just a small planet orbiting a typical star in a typical part of the galaxy. The only way to reconcile this with the idea that a society only slightly more advanced than we are would have contacted us - and Barrow and Tipler estimate that von Neumann probes will be economically viable in a few centuries at most - is to argue that some catastrophe almost always destroys a civilisation between two and six hundred years after the Industrial Revolution (or its equivalent). This pessimism may seem justified in a society facing possible nuclear devastation, social disintegration and ecological disaster.
The authors do not dwell on this. It is really a long - and fascinating - digression. The main thread of the argument is rejoined with a discussion of the end of the universe in which some form of intelligent life has basically colonised the whole, and is trying to circumvent in some way the 'heat death' predicted by thermodynamics. This part is necessarily very speculative (cosmologists do not even agree on the broad details of how the universe will end), but certainly represents just about the only feasible way in which life could affect the whole universe.
The Anthropic Cosmological Principle is an extremely complex book, and is exactly the kind of science book I enjoy, finding a peg to discuss a large number of fascinating ideas that turn out to be connected despite appearances. The earlier chapters, about the Weak Anthropic Principle, are solid expositions of material which I've seen before (and which will probably be familiar to most people with an interest in the philosophy of science). The later writing, about the stronger principles, contains much less well-known science. I suspect that these versions of the anthropic principle are probably wishful thinking, the outcome of the desire to feel that we are significant. This doesn't invalidate much of the science contained in the book, which is an excellent one. (less)
It may seem that there is not very much to be said about the anthropic principle, that it is an interesting sideline in the philosophy of science which may have a minor role in explaining why the universe is the way it is. To Barrow and Tipler, it has formed the peg around which a seven hundred page book can be written, one which takes the reader on a survey of cosmology, theology, the future of the human race, and the existence of extra-terrestrial intelligence. It is a fascinating book, occasionally rather on the mathematical side for a popular science book.
The anthropic principle, as discussed by Barrow and Tipler, comes in three varieties, with a "Final" form as well as the more familiar "Weak" and "Strong" versions. The Weak Anthropic Principle is hardly contentious. It merely says that the existence of carbon based life is an observed fact, so that the universe must have properties which make such life a possibility. Barrow and Tipler make as strong a case as is possible for the explanatory power of this idea, but I still feel that it is limited. It may explain, for example, that the universe has to be large even if the Earth is the only planet containing life (to have expanded for long enough for galaxies to form and supernovae to occur to create some of the elements we require), but not why the universe happens to be this large. All the principle states is that if it weren't, we wouldn't be here to observe the fact. However, most of what can be inferred from it doesn't actually require the presence of life; the example I've referred to could be deduced just as logically from the existence of uranium. (Life is a sufficiently complex phenomenon that it requires a large collection of such pre-conditions, so the anthropic principle is a convenient summary of many similar explanations.) It also involves the deduction of causes from effects, and that is something which requires a great deal of care, to say the least.
The stronger versions of the anthropic principle are far more contentious, and more closely related to the design arguments used to "prove" the existence of God from the appearance of design in the universe. (These arguments are summarised in an excellent historical overview which forms the first chapter of the book.) The standard strong principle says that life must evolve at some point in the history of the universe, rather than that it just has evolved. As Barrow and Tipler point out, this means that life can be said to be part of the "purpose" of the universe in some way, and this doesn't make much sense without the deduction that life must at some point have a measurable effect on the whole cosmos. This point leads into a lengthy discussion of just what this effect could possibly be, which is fascinating but extremely speculative. The first point made is that it is very difficult to imagine any way in which a species confined to a single star system could affect the universe. So interstellar travel is a necessary development, and that requires intelligence. This is the motivation behind the authors' formulation of what they call the Final Anthropic Principle, which states that intelligence must at some point arise and never die out.
The discussion of how interstellar (and, indeed, intergalactic) travel could be developed is fascinating and seems convincingly feasible. Their ideas are based on the theoretical von Neumann machine, which is basically a machine which can create replicas of itself. A von Neumann machine could be made a space probe that seeks out a star likely to have the resources to enable replication (using a strategy based on analysis of the Polynesian colonisation of the Pacific islands), and then copies itself. Given sufficient processing power to be considered intelligent and a sufficient density of planetary systems - considered likely in current astronomy - this would amount to colonisation of the galaxy by intelligent systems over a period of several thousand years.
In fact, these arguments are sufficiently convincing that they are used to support the idea that there is no more advanced race of beings in the galaxy than humanity, because we should now have been contacted by probes of this sort. (Even if they did not want to directly contact other forms of life, the action of such a probe on reaching the solar system would probably be detectable.) The idea that we are alone in the galaxy, however, contradicts the equally convincing "Copernican Principle", that there should not be anything particularly special about the Earth - we are just a small planet orbiting a typical star in a typical part of the galaxy. The only way to reconcile this with the idea that a society only slightly more advanced than we are would have contacted us - and Barrow and Tipler estimate that von Neumann probes will be economically viable in a few centuries at most - is to argue that some catastrophe almost always destroys a civilisation between two and six hundred years after the Industrial Revolution (or its equivalent). This pessimism may seem justified in a society facing possible nuclear devastation, social disintegration and ecological disaster.
The authors do not dwell on this. It is really a long - and fascinating - digression. The main thread of the argument is rejoined with a discussion of the end of the universe in which some form of intelligent life has basically colonised the whole, and is trying to circumvent in some way the 'heat death' predicted by thermodynamics. This part is necessarily very speculative (cosmologists do not even agree on the broad details of how the universe will end), but certainly represents just about the only feasible way in which life could affect the whole universe.
The Anthropic Cosmological Principle is an extremely complex book, and is exactly the kind of science book I enjoy, finding a peg to discuss a large number of fascinating ideas that turn out to be connected despite appearances. The earlier chapters, about the Weak Anthropic Principle, are solid expositions of material which I've seen before (and which will probably be familiar to most people with an interest in the philosophy of science). The later writing, about the stronger principles, contains much less well-known science. I suspect that these versions of the anthropic principle are probably wishful thinking, the outcome of the desire to feel that we are significant. This doesn't invalidate much of the science contained in the book, which is an excellent one. (less)
