Thursday, November 8, 2012

Review of "An Eerie Silence" by Paul Davies

I want my book reviews to be useful to you, the reader, who may not have read the book in question and are trying decide whether to spend your money and time to do so.  So, my purpose will not be to show you how cleverly I grok the text, but rather to lay out for you what your are likely to find interesting or helpful in the book and how much of your time will be invested.

For non-fiction books, you don't need to read every chapter, so I will break down the content of the book and try to help you decide if these are topics you are interested in.  Of course, I will only review a book I have read in its entirety.

I will also include interesting nuggets or quotes that struck me as particularly interesting.

The Synopsis

The Eerie Silence by Paul Davies

Paul Davies is a physicist and author who has been associated with the Search for Extraterrestrial Intelligence (SETI) much of his career.  He wrote this book inspired by a 2008 workshop he hosted to look for innovative ways to improve this search.


Who Should Read it?

Anyone interested in a scientific approach to the problems of searching for alien life in the cosmos. Only a general layperson's background in the sciences is required, although the background explanations in the book maybe too sketchy for some readers. If you want a more in-depth introduction to the science, I suggest reading David Grinspoon's "Lonely Planets", which takes the reader gently through basic science topics needed to understand the questions of alien intelligence.
Science Fiction writers should find a bounty of story premises here, as well.


Time investment

Modest. The book is not difficult and is reasonably well organized and written. Only 242 pages, which includes bibliography, end notes and index, and is divided into 10 chapters and an appendix.


Is it Worth Reading?

For me, the most interesting Chapters were 3, which discusses the fascinating concept of a shadow biosphere, and Chapters 5-8, which discuss recent thinking about how SETI can be improved and expanded, and the kinds of highly exotic phenomena we might encounter from highly advanced extraterrestrial civilizations if we search well enough and long enough. These chapters are rich in recent, provocative ideas.
Readers unfamiliar with SETI and astrobiology will find the entire book informative, although there are a number of other books and articles on the topic that would serve equally well or better.


Interesting Nuggets

Davies knew famed UFO researcher J. Allen Hynek, and even visited him at this home.
Davies is a member of the committee formulating what Earth's response "should" be (if any), should an alien signal be detected.


A Few Quotes

"Clearly, there could be a large number of alien probes in the solar system, and we would be completely unaware of them unless they signaled us."


The Detailed Review

"An Eerie Silence" is about the scientific search for intelligent alien life, and why and how more imagination needs to be applied to that search.  Davies notes that efforts so far to search for such intelligence have not yielded any unambiguous positive results.  He calls this the Eerie Silence, since most calculations of how many civilizations we ought to be able to detect suggest we should have seen something by now.

There are two major classes of conclusion to draw from our lack of results so far: there really aren't any nearby alien civilizations, or we're looking on the wrong places. Much of the book (and to me the most interesting parts), are about some of the places we might have missed. This is all based upon science, but is necessarily somewhat speculative. We don't really know what an alien civilization would be like, or how interested it would be in contacting us.

In Chapter 1, Davies quickly surveys the question of life on other planets and summarily dismisses UFOs. His stated reason for no longer taking UFOs seriously is not that they are strange, bit not strange enough.  The entire paranormal mythos taken as whole (a view encouraged by such leading lights as Jacques Vallee), is only too human.  My problem with this view is that we do not at all know what to expect from alien civilizations (why would there be only one?) who chose to visit the Earth.  However, if we are going to discuss SETI, we must at least as a working assumption set aside the ET conjecture for their origin, since if aliens were indeed in our own back yard, then the problem of an eerie silence evaporates before us. I am willing to go along with this for the present purpose.

In Chapter 2, Davies briefly discusses the prospects for life of any sort elsewhere in the universe. The bottom line is that we don't know, but there is real hope of knowing much more in our lifetimes, particularly in our investigation of Mars. Finding a second Genesis on Mars (or Enceladus or Europa) would be profound, and point to life being common throughout the universe.

Chapter 3 discusses the possibility of a shadow biosphere here on Earth. That is, life that does not share a common ancestry with other known life. Since we know only a small fraction of the microbial life we share the planet with, this possibility is still alive and would point to the origin of life being a common occurrence throughout the universe.

Chapter 4 is essentially a discussion of the factors in the Drake Equation, which for more than fifty years now has served as the principle mental lens for discussions about how likely we are to find signals from an alien civilization elsewhere in our galaxy. Many other books have covered the Drake Equation, but this is necessary to understanding what follows. The most interesting section in this chapter involves The Great Filter of Carter and Hanson, which is an interesting argument if a bit artificial.

Lecture on Benford Beacons at the SETI Institute
Chapter 5 is where The Eerie Silence starts to earn back its purchase price. This chapter discusses ways to both narrow and broaden the search for alien intelligence. What other ways beside signalling in the electromagnetic spectrum might we be missing? One of the most intriguing ideas is looking for a signal in the DNA of a virus or other microbe that may have been genetically engineered. Other ideas involve searching for Bracewell Probes or Benford Beacons. What we are into here is a rich set of possible scenarios, no one of which is very likely, and some of which involve ET finding us, instead of the the other way around. Like me, Davies is at least as interested in the question as the answers, and pushing forth all these ideas and asking "why not?" is way of furthering this cause. Simply saying "not at all likely" isn't interesting unless you can clearly argue why. Prior probabilities are meant to be updated with new information, a point Davies makes more than once as he discusses Bayes' Rule (subject of a future blog post).

Chapter 6 is essentially about the Fermi Paradox, or as Davies calls it, the Galactic Diaspora. He goes into the interesting research of Geoffrey Landis, modeling how the difficult and time-consuming progress of galactic colonization might progress, possible leaving big voids in the galaxy where no active colony is found, and discusses some of the things we might look for as evidence of alien colonization. Some of these are really pushing the envelope of prior probability, like the dearth of magnetic monopoles - perhaps they have all been picked over like the juicy strawberries in the patch on the last day of the season. Again, the point is to raise possibilities, not to arrive at firm conclusions.

Chapter 7 continues in this vein, but goes even further. Taking Clarke's third law seriously, Davies asks us to ditch our usual assumptions about highly advanced civilizations, developing a mind-bending concept that there may be a level beyond information in the familiar hierarchy, and even beyond that. However, Davies stakes out at least the working assumption that the laws of physics as we now know them would constrain any technology, no matter how advanced.

Chapter 8 asks the question about the post-biological future that seems inevitable if technology continues to progress at an accelerating pace. It seems likely that such a future would have already happened to any advanced alien civilization, and some of the possibilities are. Although the energy/material/information infrastructure can't be dispensed with, highly advanced technologies may manifest their conscious minds on substrates that we can't even imagine, such as a planet sized Extraterrestrial Quantum Computer (ECQ). It is possible that there are no purely biological beings beyond a certain level of advancement, although I can imagine how some would fall through the cracks. Such a postbiological consciousness might very well live entirely within a simulation of its own devising, and would be almost undetectable to us, perhaps on an ice dwarf far from a central star, where it could remain stable and undisturbed for billions of years.

As you might surmise, it can get even weirder from there. Davies' does not explore the possibility (some would say likelihood) that we are such a simulation ourselves, but if the consciousness that initiated it also lives within it, then that would imply that there is a way out, although our simulated universe might be more interesting.

The remaining chapters of the book (9 and 10, which could easily have been one chapter) take us back home, and ask the question of what would happen if the SETI search were successful - not so much of a local Bracewell probe or other artifact, but a detection of an alien electromagnetic signal. What would be the implications, and how would an answer be composed, and who should do it? In my view, a nice, neat, unified and academically satisfying response would never happen. As with all "should" questions, there are no clear answers. If you have never thought about these questions before, you will probably find Davies' discussion interesting; for example, what would be the implications for religion and theology? However, I found these chapters largely review, and relatively unimaginative.

The book closes with a discussion of whether we might in fact be alone after all, and that the silence is truly a silence, and not just a limited search. After all, the are many factors in the Drake equation that we have no idea how to bound. If any of them are much smaller than we we presently guess they are, then the silence may in truth be The Silence. Until we know much more than we do now, we can't discard this possibility. The responsibility this would place on us is frightening.

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