The Anthropic Cosmological Principle

by John D. Barrow, John D. Barrow, Frank J. Tipler

Ever since Copernicus, scientists have continually adjusted their view of human nature, moving it further and further from its ancient position at the center of Creation. But in recent years, a startling new concept has evolved that places it more firmly than ever in a special position. Known as the Anthropic Cosmological Principle, this collection of ideas holds that the existence of intelligent observers determines the fundamental structure of the Universe. In its most radical version, the Anthropic Principle asserts that "intelligent information-processing must come into existence in the Universe, and once it comes into existence, it will never die out."
This wide-ranging and detailed book explores the many ramifications of the Anthropic Cosmological Principle, covering the whole spectrum of human inquiry from Aristotle to Z bosons. Bringing a unique combination of skills and knowledge to the subject, John D. Barrow and Frank J. Tipler--two of the world's leading cosmologists--cover the definition and nature of life, the search for extraterrestrial intelligence, and the interpretation of the quantum theory in relation to the existence of observers. The book will be of vital interest to philosophers, theologians, mathematicians, scientists, and historians, as well as to anyone concerned with the connection between the vastness of the universe of stars and galaxies and the existence of life within it on a small planet out in the suburbs of the Milky Way.

Genres: Science, Philosophy, Physics, Nonfiction, Psychology, Mathematics, Astronomy

736 pages, Paperback

First published January 1, 1984

About the author

John D. Barrow was a professor of mathematical sciences and director of the Millennium Mathematics Project at Cambridge University and a Fellow of the Royal Society.

He was awarded the 2006 Templeton Prize for "Progress Toward Research or Discoveries about Spiritual Realities" for his "writings about the relationship between life and the universe, and the nature of human understanding [which] have created new perspectives on questions of ultimate concern to science and religion".

He was a member of a United Reformed Church, which he described as teaching "a traditional deistic picture of the universe".

Reviews

[Andrew Gillsmith · Rating 3 out of 5]

There are some great ideas in this book, even if some of them are now a bit outdated (or at least out of fashion).

Unfortunately, the authors failed in their stated goal of presenting the material in a manner that would be accessbile to non-techical readers.

If you are a physicist or mathematician, this book is a treasure. Otherwise, there are better treatments of the anthropic principle out there.

[Ushan · Rating 4 out of 5]

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.

[Manuel Alfonseca · Rating 4 out of 5]

ENGLISH: This is a very hard "popular" book on cosmology. It includes a good history of the development of this science, together with a description of some of the theories. Of course, it is now a little dated, since it was written 30 years ago, and cosmology is now quite different from what it was at the time. Anyway, it deserves to be read, although the abundance of equations will stop many people from trying.

The authors dedicate several chapters to their own pet theories, which can be summarized thus:

1. We are the only intelligent species in the universe. See my blog post about this here: http://populscience.blogspot.com/2015...

2. Once intelligence has appeared in the universe, it cannot disappear. See my blog post about this here: http://populscience.blogspot.com/2015...

ESPAÑOL: Este es un libro de divulgación muy difícil sobre cosmología. Incluye una buena historia del desarrollo de esta ciencia, junto con la descripción de algunas de las teorías. Por supuesto, ahora está un poco anticuado, ya que fue escrito hace 30 años y la cosmología ahora es bastante diferente de lo que era entonces. De todos modos, merece ser leído, aunque la abundancia de ecuaciones impedirá que muchos lo intenten.

Los autores dedican varios capítulos a sus teorías favoritas, que pueden resumirse así:

1. Somos la única especie inteligente en el universo. Sobre esto publiqué un artículo en mi blog: http://divulciencia.blogspot.com/2015...

2. Una vez ha aparecido la inteligencia en el universo, ya no puede desaparecer. Sobre esto publiqué un artículo en mi blog: http://divulciencia.blogspot.com/2015...

[Rama Rao · Rating 5 out of 5]

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.

[Alex Shrugged · Rating 5 out of 5]

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.

Update (2025-Sep-27): As I recall, this is my third full reading of the book. i still don't understand it all, but I'm picking up more of it. I've tried to work out some of the formulas and that worked out OK, but it took a long time. I finally gave that up and took the authors' word for it.

[David · Rating 5 out of 5]

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...

[Mientras Leo · Rating 3 out of 5]

No ha sido la lectura que yo esperaba, la verdad.

[Mary-Jean Harris · Rating 4 out of 5]

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.

[Alex]

Mind meltingly scientific and bigger picture generalizations at the same time.

[Paige McLoughlin · Rating 5 out of 5]

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)

[Amedeo Balbi · Rating 4 out of 5]

Il principio antropico è uno dei concetti più controversi in cosmologia e, per la verità, è discutibile il fatto stesso che possa essere definito un 'principio'. E' l'idea che molte delle caratteristiche dell'universo sono influenzate dal fatto che esiste un osservatore: per esempio, il fatto che viviamo in un universo che ha 14 miliardi di anni non è casuale, ma è una conseguenza del lungo periodo di evoluzione necessario allo sviluppo di forme di vita intelligenti (noi) sulla superficie di un pianeta (la Terra). Barrow e Tipler fanno un inventario delle idee antropiche in diverse discipline: fisica, astrofisica, cosmologia, biochimica, ecc. Il risultato è uno straordinario excursus nella scienza moderna, che è apprezzabile anche se non si sposa la prospettiva finalistica che sembra emergere tra le righe del libro.

[Alex Lee · Rating 4 out of 5]

This is a flawed but interesting book. Some of the science is dated but that doesn't matter. The question in this book is, can we use science to discover if sentience has significance in the universe? How special are we humans? Is the universe made for us, for intelligence, or are we an accident?

Because these are philosophical questions the first thing the authors do is defame philosophy as being the wrong approach to answering such questions because science has all the right criteria: (objective, truth oriented, evidence based, etc). Nonetheless there is a ton of philosophy in here in part because to answer philosophical questions with science, one has to show the connection between philosophy and science. In fact, both disciplines used to be one, although the birth of modern scientific practice split science from philosophy.

Despite the extraordinary number of pages in this text, the authors approach is simple. They want to show how unique life on Earth is, to both imply that we are special AND to estimate how likely/rare sentient life is in the extended universe/galaxy. The problem with their extrapolation is double.

1. They do not have all the criteria to determine the likelihood of sentience.
- they lack the thresholds for where sentience can emerge, since only humans are the model
- they treat their statistics as "flat". For instance, they argue the unlikelihood of our universe based on the sheer number of possible quantum states (1 out of 10^????) but not all quantum states are equal, nor is it clear how much exactness a quantum state could have among other states.

2. They assume that sentient life can only be life that has a record of itself somehow. This is more problematic because while they assume that all humans are humans -- this criteria alone can be used to argue for the inferiority of certain humans. This cultural standard is reasonable to use because we need a sufficiently technological species to make "noise" so that we can detect them.
However this standard makes it so that it clear the authors have an ideal in mind for what life can be and that life is necessarily modelled on their idea of what we humans are like.

Of note in the last point is that the scientists use statistics and science to establish their authority but then use the tools of science "backwards" that is they attempt to reason from the result... this is related to the second point in that while they only have one universe in evidence (ours) they use that single data point to try and determine the likelihood of all universes. Like that of sentience, it is clear these authors do not really have any clear definition of what they are attempting to find, except that "it should be like us" somehow.

Given all of these issues, the most I can say is that this book, while futile, serves an ideological purpose -- to try and make scientists the authority for all meaningmaking. If scientists can answer a philosophical question through the sheer magnitude of scientific babble (as these authors are wont to do) then scientists should be the authority in other areas as well. This kind of intellectual envy (authority stealing) is what is most distasteful about the book, as it blinds us to the possibly of having values other than those the authors want us to have. At best, this promotes a kind of intellectual masturbation by pushing us to consider things seriously when we don't have any basis for considering those things. At worse, it blinds us into thinking that one group of people, scientists, can provide for us all the meaning we need in life and existence, and that's ridiculous. This is exactly why scientists would argue against religion, and here, some scientists are seeking to fulfill the same role, with them as the final word. Stupid.

Still, it shows us how scientists can think, and how they should not think, when they try to extend their methods beyond experience (as Kant would say).

[Ron Peters · Rating 4 out of 5]

“The cosmos is within us. We’re made of star-stuff. We are a way for the cosmos to know itself.” Carl Sagan

This is a book about teleology, physics, cosmology, and humanity. I was led to it by a couple of different Brian Cox videos. It is one of the most difficult books I’ve read, and I didn’t understand large swathes of it. But it is chock-a-block with fascinating concepts, and those ideas made the parts I understood enjoyable.

The universe has several features—such as its age, the speed of light, and other physical constants—that seem precisely tuned for life. According to the strong version of this principle, the universe’s structure is constrained by the presence of intelligent observers and must possess properties that permit the development of life, suggesting intentional design.

The first two hundred or so pages are a ‘history of ideas’ review of teleological thinking. These parts are mainly philosophical and, in terms of difficulty, are what you’d expect in an undergraduate philosophy course.

Chapters 4 through 6 are a discussion of the anthropic principle applied to physics, astrophysics and cosmology. These are thoroughly mathematical and the best I could do was to skim the textual portions and glean what I could.

Chapters 7-9 are more text-focused and straightforward, including the one on quantum mechanics and the anthropic principle, which is surprisingly accessible. The discussions on the anthropic principle and biochemistry, and arguments about extraterrestrial life are engaging. The final chapter covers the universe’s future and, while very mathematical, presents challenging ideas. For example, these are the last two sentences:

“At the instant the Omega Point is reached, life will have gained control over all matter and forces not only in a single universe, but in all universes whose existence is logically possible; life will have spread into all spatial regions in all universes which could logically exist, and will have stored an infinite amount of information, including all bits of knowledge which it is logically possible to know. And this is the end.”

The book presents a range of unusual physics concepts and is almost worth reading just for its references. It covers topics like Teilhard de Chardin’s The Phenomenon of Man, intelligent extraterrestrial life, computer simulations as possible realities, and the legitimacy of artificial intelligence as life forms.

My interpretation is sure to be over-simplified, but I accept the Weak Anthropic Principle: our existence is tied to the universe’s properties since, if things were different, we wouldn’t be here. We lack evidence to prove or disprove the Strong Anthropic Principle, especially since we don't know whether the universe is finite or infinite. If it’s infinite, countless worlds like ours should exist simply due to random developments.

[Simon Mcleish · Rating 4 out of 5]

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.

[Max Blair · Rating 3 out of 5]

I decided to read this after seeing someone mention it in an interview, saying that it talks about the role of intelligent life in the cosmos in the deep future, a subject I find quite interesting. I gave it a couple tries and put it down but finally committed to get all the way through it this past month. To be honest, I'm not sure it was worth it. The math and physics are well beyond my ability to follow. That said, by researching what some of the terms and symbols in the equations presented mean I did learn a fair bit about cosmology and refreshed some of my lapsed high school math knowledge.

The thrust of the book, as I understand it, is to show that, by the mere consequence of our existence, there is a very strong selection effect on the type of universe we observe. This is the weak anthropic principle. I either didn't follow or don't remember the arguments that were made for why this is a better explanation than fine tuning.

In the very end of the book, the authors do present a compelling vision of the deep future wherein intelligent life processes infinite information as the universe approaches a final singularity. They even go as far as to say that, once the Omega Point is reached, intelligent life will have completely filled all logically possible universe and have processed everything that's possible to know. An intriguing vision whether I was able to follow the math and physics that the use to argue for it or not. On the way to that future life becomes capable of harnessing matter and energy and truly cosmic scales which is fun to think about whether it becomes a reality or not.

[Paige McLoughlin · Rating 5 out of 5]

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.

[Michal Paszkiewicz · Rating 4 out of 5]

The authors present both the history of science and the universe as part of a discussion of whether the anthropic principle is of any scientific use. This proves to be a question that can be applied to most of the scientific achievements of our age and the authors present a good argument for at least the position that anthropic reasoning may have at the least, achieved scientific results that have helped improve our understanding of the universe. While the study of the omega point remains a slightly strange line of reasoning, it was good to see all the arguments presented rather formally, no equations spared. I have a huge respect for the authors, who must have spent an incredible amount of effort and time to write about all the concepts present in this book with such details. I may return to this review once I've read Nick Bostrom's critical answer, but till then, I think this book is well worth reading largely due to the immense wealth of knowledge present in it.

[Marco · Rating 4 out of 5]

This had the potential to be one of the best science books ever, due to the breadth and depth of the subject, the treatment and the authors.
If not for the fact that it is really badly written: the level is completely inconsistent between easy descriptive parts and parts which cannot absolutely be understood if you have no solid foundations in general relativity theory and cosmology, which are this useless in their mathematical details. It is also full of typos and errors in formulas (some added by bad translators, many present in the original).
It is really a pity, as the book (even if somewhat dated) would be a milestone in science writing, but it defies and deranges attentive readers who really want to get into it.

[Dan Zarfati · Rating 4 out of 5]

The book is big, and a good part of it is very technical, with many equations that I would not understand, the book is dense so it does take time to read if you are a layman like me. Still, it has plenty of interesting ideas and theories. I would say that a good part of it is a bit obsolete, that part that deals with space travel and whatnot. Though a lot of people considered this anthropic proposition nonscientific I understood it as perfectly valid and left me wondering if this is not the case we are living in. The case for an artificial universe is building.

[Simone Camosso · Rating 5 out of 5]

Non esaustivo ma apre molte porte ad interrogativi. Esplora le più recenti teorie in tutti gli ambiti: filosofico, fisico, chimico e cosmologico … un libro più da consultare invece che da leggere ma e’ decisamente pieno di spunti e idee nuove.

[Victor Modesto · Rating 5 out of 5]

Disagreed with the central argument of the book was found it extremely well written and stimulating.

[Will Lawrence · Rating 4 out of 5]

For how complex the topics are in this book, explains them pretty well sometimes. Other times gets too into the equations without explaining them. Clearly meant for physics graduates

[Carol · Rating 1 out of 5]

I am done with this. It probably belongs on a shelf for books I didn't finish, because I just could not stand to read any more. The first chapter was interesting to me, and if that had been the whole book, I could have given it 4 stars. But it wasn't.

I just never felt that the author was communicating with me. He kept not answering my questions and answering questions I didn't ask and didn't care about.

The last straw for me was his claim that (4 pi/3) was close to 1. OK, on one hand, it's a reasonable thing, if you're dealing with numbers that include large (positive or negative) powers of ten. For those magnitudes, I guess that a multiple of something around 4 isn't hugely different from one. But it that's the meaning you want to use for "close to 1" please don't expect me to be amazed that it's so close, and that people (supposedly scientists) use this to argue that the value might actually BE 1.

Also, the writing struck me as turgid, and the formulas were never explained in any detail, just presented as sort of a fait accompli.


Previous comments on the book.
This book is not really what I expected. The first two chapters were OK, if sometimes slow going. But when I got to chapter three, I had to say this:

This book reminds me of Lord Dorwin, in the novel Foundation. Asimov used him to illustrate the decadence of the dying interstellar empire. Lord Dorwin took snuff. When speaking (unless he was very excited) he dropped the letter "r". He was an expert on the Origin Question, the one dealing with what star/planet was the original home of mankind. I'll quote part of a paragraph from his discourse on the subject:
"I've got the wuhks of all the all the old mastahs, the gweat ahcheologists of the past. I wigh them against each othah, balance the disagweements, analyze the conflicting statements, decide which is pwobably cowwect, and come to a conclusion. That is the scientific method."

I skipped Chapter 4.

[Autumn Kotsiuba · Rating 3 out of 5]

Aaaand my brain is mush.

The anthropologic cosmological principle is basically a teleological argument--the universe has a purpose, was created for a purpose, and humanity is extremely connected, if not central, to that truth.

Full disclosure, I had to skip over a good chunk of the math; the only physics I know is what I've taught myself (I skipped it in high school) so a lot of the mathematical arguments were beyond me. But, oh my goodness, the historical, philosophical, and cosmological discussions were fascinating.

I'm not qualified to adequately judge or even analyze the principle, so here's just a few thoughts/quotes I want to keep for myself later:

"The future is not what is was."

"An object is nothing else but the totality of relations unified by the imagination." (Don't agree but still a cool thought)

Turing is instrumental to the theory, so, hey, that's pretty neat.

"We must separate coincidence from consequence."

The Von Neumann Probe is the trippiest thing I've ever tried to understand.

An anthropic perspective exists in both western and eastern thought; some think it may even be universally considered.

Why does space have multiple dimensions but time only one?

WAP, SAP, and FAP are really complex, rely on a circular argument, and therefore can never be really proven (Well, okay, WAP's principle of observer bias is a given). Really interesting to learn about, but I'm not sure exactly how helpful it is.

[Damon · Rating 5 out of 5]

In my view, this is one of the two greatest and most classic books that stand in critique to dominant materialistic wing of the life sciences. The other book would be ‘the mystery of life’s origin’ when I first began investigating the origins of life I had to slog through a lot of really bad books, but then I found this book and ‘the mystery of life’s origin’, and it really got me on the right track.

[Abol · Rating 4 out of 5]

Tremendous insight into the age of the universe needed to make us, information processing machines, happen and consider the why-questions and the age of the universe or its ten trillion light years width.

[David · Rating 3 out of 5]

Paperback

[H Wesselius · Rating 1 out of 5]

With the exception of the first more historical chapters of the book, the book is barely accessible to the reader. There are far better books in this genre, try Paul Davies or Brian Greene