This is a collection of papers gathered under three large themes involved in contact with extraterrestrial civilizations. It has relatively little to say about the prospects for our discovering such civilizations (or their discovering us) and much more to say about what happens once we do make contact, with a strong multidisciplinary approach. The writing ranges from general audience-friendly to mildly technical -- I wouldn't say that any of the papers are specialist-only, in keeping with the multi-disciplinary approach.
The first section (Does Extraterrestrial Life Exist?) does take up the core debate, after a substantial introduction that lays the groundwork. Seth Shostak's paper discusses the current state and presents the Drake Equation. The other papers in the section focus in on the "L" factor in the equation -- how long-lived we can expect civilizations capable of communicating with us to be, usually taken to be the factor least well-known and probably most determinative of our chances of detecting alien civilizations. Perspectives from archaeology and biology are especially interesting, attempting to provide some grounding for thinking about a factor for which we have no strong data. One interesting point is that L partly depends on our own technology for detecting signals -- it may well be that there is a short window, even in a long-lived civilization, during which the type of signals we can detect -- electromagnetic signals -- can be expected, before a civilization moves on to some other technology now unknown to us.
Reactions to Discovering Life Beyond Earth takes up how we are likely to react to the news that we have detected an alien civilization. Two papers present survey research, showing that, in fact, a majority of people surveyed in the US do believe life exists beyond the earth. If you are a UFO skeptic (I am), you'll be relieved to find that belief in life beyond the earth does not correlate with belief in UFOs as extraterrestrial visitors or in New Age beliefs -- a sign that the field has moved on to have a standing of its own in the general culture. Other points I found interesting involve how intertwined reactions and responses are likely to be with our own complicated politics -- we imagine a coordinated, single response, but there are likely to be as many as there are factions, political and otherwise, who interpret the news and its significance differently from one another.
The final section (Communication with Extraterrestrial Intelligence) takes up the sometimes under-appreciated problem of finding a way to exchange communications -- how do we, or other civilizations, construct a message that will be understood by an unknown type of intelligence, with unknown biology, unknown culture, unknown history, unknown interests (even if those categories themselves are applicable)?
In that final section, I found some very welcome notes of skepticism. A paper by Jason Kuznicki offers some observations from the experience of Jesuit missionaries with native North Americans. Much as the Jesuits may have shared with the people they encountered, they found communication very difficult, moreso than they expected. We imagine swapping words for objects, like we see in movies -- drawing a map or a picture and naming objects to elicit the corresponding words from the other parties. But the Jesuit missionaries found that even the very concept of an object wasn't as shared a concept as they thought. Our beliefs about primitives in thought and communication may be extremely naive.
I think that sometimes our imagination is just not equal to the task of understanding how different an alien civilization might be. We imagine that depictions of basic science or math (e.g., a series of numbers represented as dots) or a picture showing the location of our home planet will be something we can start a conversation with. But will aliens understand our drawings? Will they even understand that they are drawings at all? The concept of pictorial representation is more complex than it looks -- just ask philosophers. We don't even know that an intelligent alien species will have vision, in the sense of "vision" familiar to us.
The irony to the search for extraterrestrial intelligence could turn out to be that any civilization we encounter will be so utterly different that we cannot understand any of what they communicate to us, or even that we cannot recognize them as intelligent at all. Personally, I don't find that possibility depressing -- it would only serve to register on us the vastness of possibilities relative to our capacity for understanding. Something to be awed by, not depressed.
This is a provocative book, and one that presents some perspectives on the subject matter that we often miss in discussions that lack its multidisciplinary perspective. Even if you've read a great deal of discussions that focus on the scientific aspects -- astronomy, exobiology, etc. -- this provides something you may have been missing.