Your complimentary articles

You’ve read one of your four complimentary articles for this month.

You can read four articles free per month. To have complete access to the thousands of philosophy articles on this site, please

SUBSCRIBE NOW

Books

The Search for Extraterrestrial Intelligence by David Lamb

Edward Ingram gazes heavenwards and tells us about the Search for Little Green Men.

Most books on extraterrestrial intelligence (ETI) are awful. David Lamb’s book, The Search for Extraterrestrial Intelligence, is an exception. I enjoyed it immensely.

Lamb starts by discussing the assumption that, should we find an ETI civilization (or they us) communication between them and us, and vice versa, would be easy. This assumption is prevalent within the SETI (Search for ETI) community and, as Lamb argues, is problematical. First, there’s the problem of recognising a message for what it is – a message. Second, there’s the problem, once one knows one’s detected a message, of deciphering it.

The first, as Lamb argues, is easy, at least in principle: all languages are nonrandom. If one were to see a human language in code form, one would be able to tell it was saying something, although deciphering it – determining what that something was – might prove difficult. This said, a coded message, given a casual glance, although not random, might appear random, and this is especially so apropos SETI given the amount of noise coming from outer space (SETI researchers at present scan the heavens for radio messages from outer space).

The second problem is more difficult than is sometimes thought. Lamb describes how SETI researchers Drake and Sobel encrypted a message such that it should have been easily decipherable and gave it to Nobel laureates to decode. None succeeded, although all knew it was designed to be decrypted. The assertion one sometimes hears, that communication with aliens would be easy, is open to question. Lamb discusses this, and related issues, well. Without common reference points, it’s difficult to see how communication between humans and aliens could get started.

Lamb progresses to the status of SETI as a science. Again, his discussion is good. He points out, for example, that the scientific status of SETI is mixed, given that, if it is a science, it’s unusual in that nobody is sure whether it has a subject matter. Nonetheless, he argues, SETI has done a service in sharpening people’s thinking as to what constitutes life, its origins, and its potential. Here, I think, Lamb is on solid ground. However, to my mind he doesn’t follow up his argument enough. He doesn’t, for example, discuss the views of those complexity theorists who argue that the emergence of life is virtually inevitable; and neither does he much discuss speculations to the effect that exotic forms of life may reside inside stars or on the surfaces of neutron stars, or the view that spiral galaxies be considered alive. And, at a mundane level, although Lamb allows that primitive life may exist in interstellar clouds, and that certain satellites – Europa, for example – may contain life, he doesn’t discuss the possibility that life as we know it (i.e., carbon-based life) may exist in the atmospheres of gas giants such as Jupiter and Saturn. Such omissions are unfortunate. This said, within his own, albeit anthropocentric, terms he does a reasonable job.

Lamb also provides good coverage of the Drake equation. This relates to estimating the number of ETI civilizations. It includes variables such as the fraction of stars that have planetary systems, the fraction of planets in such systems, the fraction of planets that house life, and so forth. Lamb makes two points: first, the Drake equation involves piling guesses upon guesses (nobody knows the percentage of stars that have habitable planets orbiting them, for instance); second, in spite of this, the Drake equation has proved useful in assisting people in ways of thinking about ETI. The equation’s critics often miss this second point.

Much of the rest of the book is concerned with the staple fare of ETI discussion – UFOs, the possibility of an ‘organic’ chemistry based on silicon (most unlikely), the possibility of life on Mars, and so on. Lamb covers such topics solidly, though, again, there are omissions; he doesn’t, for example, discuss extremophiles (organisms that thrive in what are, seemingly, the most inhospitable regions on Earth – in boiling water, for example).

Towards the end of the book Lamb tackles the case against the existence of ETI. This is where the book’s main weaknesses lie, for there are three major arguments against the existence of ETI, and one minor one, and each is, to a greater or lesser extent, philosophical. Yet Lamb tackles only one of the major arguments, and doesn’t touch on the minor one. The major arguments are (a) the evolutionary argument, (b) the Doom Soon argument, and (c) the Fermi argument. Lamb covers only the Fermi argument.

The evolutionary argument is that intelligence is so unlikely to evolve that it is virtually inconceivable that it has evolved more than once in our galaxy, and possibly it has evolved only once within the observable universe. The majority of theoretical biologists accept the argument. I won’t go into the specifics of it. Suffice to say that Lamb’s omission is serious, if only because so many well-versed in the ETI debate consider the argument sound.

The Doom Soon argument is that intelligence is likely to evolve at the end of the ecological viability of the system that houses it – thus, as soon as intelligence emerges on a planet, odds are it will be snuffed out. The status of this argument is disputed. Again, I won’t go into its details. I’ll only say that, as with the evolutionary argument, its omission is unfortunate. Many people take it seriously.

Lamb covers the Fermi argument well. The argument comes from the physicist Enrico Fermi and postulates that, if intelligence is rampant throughout the universe, then ETI should be here and noticeably here (so noticeably here, according to recent defenders of the argument, that we would not be here, for the aliens would have done us to death – or, rather, billions of years ago they would have done to death the bacteriological slime from which we evolved).

Lamb argues, correctly in my view, that the Fermi argument is more forceful than is commonly imagined. It is true, for instance, that interstellar travel, upon which the argument depends, may be more difficult than is sometimes supposed – but is it that difficult? There are so many proposed mechanisms by means of which humans may travel to the stars that it seems inconceivable that, if ETI is common, that some have not mastered it and have started a campaign of pangalactic colonisation. Likewise, it is conceivable that certain ETI may be altruists, as UFOlogists often claim, but if ETI is common, some ETI must be like us, and, given this, they must do what we have done, and continue to do – obliterate competing species, place others in animal laboratories, and so on. In this way, the Fermi argument suggests that either interstellar travel is impossible – in which event we will probably have to revise physical theory, substantially – or ETI is monstrously rare. Lamb plumbs, I think correctly, for the latter conclusion.

This brings us to the minor argument. It’s minor only in the sense that it’s supremely contentious. It is that life, once it emerges in a universe, must exist forever. However, the eternal life postulate, as it is called, places severe constraints upon the nature of the universe – only a minority of all possible universes are capable of supporting eternal life. One of these constraints is that intelligent life evolves only once in any given universe (the reason is technical: a plethora of life, it transpires, uses up the usable energy within the cosmos too quickly).

It is a shame that Lamb doesn’t cover this argument, for, although it is contentious, it gets to the core of the ETI debate. There would be no philosophical problem in finding life in outer space – we should expect, from evolutionary principles, it to be common – but there would be a philosophical problem in finding no extraterrestrial life – such would upset evolutionary theory. Likewise, there would be no problem in finding ETI, providing it is rare (note: the ETI debate is not about the existence of aliens; it’s about the existence of intelligent aliens). But there would be a huge problem in finding abundant ETI. And there would be an even huger problem in discovering that ETI doesn’t exist, for then we would be forced to ask, “Why does the universe appear to be so felicitously ‘designed’ for our [eternal?] existence?” In this, Lamb omits discussion of the so-called anthropic principle – the idea, in its strong forms, that humanity is, in some sense, “meant to be here”. All ETI debate, directly or indirectly, touches on the anthropic principle.

So what are we to make of Lamb’s book? It’s good, very good. It covers the basic arguments on ETI, and those areas of the topic that it discusses, it discusses well. Moreover, it’s written in a reasonably accessible style. As such, it’s indispensable reading for anyone interested in the subject. But it doesn’t tell the whole story. Good as it is, it could have been much better.

Edward Ingram is Fellow in Philosophy at the School of Psychology at the University of Wales, Bangor.

• The Search for Extraterrestrial Intelligence: A Philosophical Inquiry by David Lamb (Routlege) £11.99 pb. ISBN 0415243424.