Extraterrestrial Life & Jared Diamond
I'm sure some of my readers are familiar with Jared Diamond, author of Guns, Germs, and Steel, as well as Why Is Sex Fun? and Collapse. His book The Third Chimpanzee was recently reissued and I've been reading it. Most of the time Diamond is very convincing, and he is so in this book up until he turns his attention to the likelihood of finding extraterrestrial life in our galaxy and the consequences of doing so.
He argues that, despite the vast number of stars in our galaxy, it is unlikely that there are any advanced civilizations nearby. His argument is basically twofold: First, since the level of intelligence necessary to create radio (and therefore be able to communicate with lifeforms on other planets) only evolved once on Earth, and is thus not only not inevitable, but unlikely on other planets. So unlikely that there won't be any radio-using civilizations anywhere near us, accounting for our lack of contact, thus far, with any extraterrestrial civilizations.
And second, that our species has only had radio for 69,999/70,000ths of our seven-million-year-history, and that it came about just as we gained the ability to destroy ourselves (through nuclear weapons or environmental destruction), and so the window between inventing radio and self-destruction will be very short. As such, it is unlikely that any other civilizations are in that brief window right at the same time humans happen to be.
And, lastly, he argues that the fact that we aren't going to find any advanced extraterrestrial civilizations in our interstellar neighborhood is a good thing, since they would surely exploit and/or enslave us as humans have to other human populations throughout history.
Let's take these arguments one at a time. First off, it's not entirely certain that human-level intelligence has only evolved once, in primates (I say "primates" and not humans because Neanderthals and other now-extinct primates may have been as intelligent as humans as well). Some believe that dolphins may, in fact, be as intelligent as humans, though this remains to be proven. Even if, however, no other species alive today approaches or equals human intelligence, that is not to say that intelligence has not, in fact, unsuccessfully evolved other times. It is entirely possible that under other circumstances an intelligent species would not have had time to develop enough tools and technology to survive.
Diamond uses the woodpecker as an example of how contingent the evolution of intelligence might be: woodpecking is, apparently, a very successful survival strategy, but despite its value, it only evolved once, and if those birds had not developed it, it would never have evolved and that niche would never have been filled. But, as I already noted, we don't know that intelligence only evolved once.*
We can be pretty sure that intelligence only developed to the stage of creating radios once, but that's not to say that intelligence might not have kept cropping up until one species with it was successful and ended up with radios. And also, despite how contingent the development of both intelligence and woodpecking may have been, both did, in fact, happen. Diamond contends that "radios had a vanishingly small low probability of having evolved here." That may or may not be true.
We can't rewind history and see if evolution would have produced radios any more than we can rewind history and see if there would have been a Holocaust without Hitler. I agree with Diamond in that there is no evidence that intelligence was inevitable, as many contend, but I can't go with him to the other extreme and say it was nearly impossible. I just don't see how we can calculate those probabilities, in hindsight, accurately enough to declare it so unlikely it can't have happened again anywhere near us. I'm willing to go along with highly unlikely, but not so unlikely that we can just assume the likelihood is basically zero as Diamond does.
On his second argument, that "Earth's history... suggests that any [radio-capable civilizations] that might exist are short-lived," and that they "probably reversed their own progress overnight, just as we are now at risk of doing" seems like a lot of speculation to me as well. We only have a sample size of one, certainly, but we have, as yet, not destroyed ourselves. I am actually quite pessimistic as to our species' chances of survival, but nonetheless I don't see how we have enough information to assume that other advanced civilizations must have destroyed themselves almost the instant they invented radio. Once again, I might be willing to say that it is likely, but not virtually certain as Diamond does.
As such, since I don't think we can assign the chance of intelligence evolving on other planets a probability so close to zero, or the chance of radio-capable civilizations so close to one, as Diamond does, I don't think we can safely assume that the vast number of stars in our galaxy, or even our corner of it, do not support advanced civilizations. If we assign the first a very small but non-zero probability, and the second a very high probability but less than 1, then the odds at least allow for the possibility of nearby extraterrestrial life, even if they do not mandate it.
On the argument that aliens will inevitably exploit and enslave us, and that it is therefore foolish to advertise our presence, I don't see how that necessarily follows either. While it is true that humans have almost always exploited, displaced, eradicated, and enslaved other groups of humans when encountered, and still do today, it is becoming -- very slowly -- less and less acceptable to more and more people to do so. While I do not believe that we will ever completely rid ourselves of our genocidal tendencies, I do think it is possible that someday enough people will agree that is morally and ethically wrong to exploit, displace, eradicate, or enslave other intelligent beings to make it difficult for any humans wishing to do so.
I'm not necessarily talking about a Gene Roddenberry-esque future where humans are all evolved and utopian here, either. For instance, I could imagine a circumstance like H. Beam Piper's novel Little Fuzzy. In that novel, a company owns a planet on which a prospector discovers small, fuzzy humanoids living. The prospector begins to suspect the fuzzies are sentient (or "sapient"), which would be bad news for the corporation, as by law it would lose its claim to the planet. So the corporation starts up a campaign to prove the fuzzies aren't sapient which eventually comes to a head when a company scientist kills one of the fuzzies. The issue of fuzzy sapience then becomes a point of law, because the killing will be murder if the fuzzies are, in fact, sapient, and not if they are "just animals." It is eventually proven in court that the fuzzies are sapient (it turns out they have learned English but were speaking it in a frequency range humans couldn't hear) and the scientist is convicted of murder and the company loses its claim.
Was it necessary for a Roddenberry-esque utopia to develop in this novel in order for humans to encounter an intelligent alien race and yet not exploit, eradicate, or enslave them? No. This scenario presents a case where a segment of human populations does, in fact, want to do all those things, but where enough humans have decided such things are unethical and immoral to make it illegal to do so. Could such laws be passed and enforced? Perhaps. Certainly they can be passed, as already International Law makes genocide a crime, but, as of now, enforcement is sadly lacking. But I do not see it as unreasonably utopian or unrealistic to think that laws such as these, forbidding the taking of planets from other sentient beings and making the killing of a non-human sentient murder, could someday be law in a spacefaring human society.
As such, while I agree with Diamond that there is a very distinct danger that advertising our presence is unwise and that any aliens we might encounter will, in fact, attempt to exploit, eradicate, displace, or enslave us, it is not inevitable as Diamond contends. As genocide and mass-murder become less and less acceptable to more and more people, it is within the realm of possibility that someday such things are outlawed, and it is possible for us to meet other alien civilizations that, even if some of them are disposed to do such things just like some humans are, do not tolerate such behaviors.
In the end, I find Diamond's arguments just as unconvincing as the arguments on the other side that finding extraterrestrial life is "inevitable" and that any civilization advanced enough to communicate or travel through interstellar distances must be ethical and peaceful. I think the best we can say is that it is likely, but not certain, that extraterrestrial life exists within our interstellar neighborhood, that it is likely that radio-capable civilizations are capable of destroying themselves but that the likelihood of them doing so is unknown, and that it is very possible that any extraterrestrial civilization will try to eradicate, displace, enslave, or exploit us, but what that the probabilities are difficult to determine at this point. Not very satisfying, but sometimes the answer is, simply, we don't know.
After all, twenty years ago we were certain that gas giants couldn't form in the so-called "green zone" -- the zone around a star where planets would be able to support Earthlike life -- but among the few planets we have so far detected several have been gas giants in the green zone. Extrapolating for the entire universe from the data found on our own planet or own solar system has proven before to fraught with inaccuracy, and I don't have as much faith in them as Diamond seems to.
*Though, of course, there is no evidence that intelligence evolved in any other species in the past, and, in fact, I doubt it did, as there is no evidence to support it, but since we are dealing in hypotheticals here anyway, I believe I have a valid point.