In his new book The Zoologist’s Guide to the Galaxy: What Animals on Earth Reveal About Aliens–and Ourselves, Cambridge zoologist Arik Kershenbaum purports to tell us what intelligent aliens will be like when we meet them:

This book is about how we can use that realistic scientific approach to draw conclusions, with some confidence, about alien life – and intelligent life in particular. (p.1)

Now, that won’t be for a long time, and they will even then be far more advanced than us:

We are absolutely in the infancy of our technological development, and that makes it exceptionally likely that any aliens we encounter will be more advanced than us. (p.160)

The chances of us encountering intelligent aliens [anytime soon] is so remote as to be almost dismissed. (p.320)

Even so, this is what aliens will be like:

One way to prepare ourselves mentally and practically for First Contact is … to reconcile ourselves to the fact that there are certain properties that intelligent life must have. … their behavior, how they move and feed and come together in societies, will be similar to ours. …

[Aliens and us] both have families and pets, read and write books, and care for our children and our relatives. … this situation is actually very likely. Those evolutionary focus that push us to be the way we are must also be pushing life on other planets to be like us. (pp.322-323)

And this will be their origin story:

Perhaps if there is a universe story describing the evolution of humans wherever they may live, it might go something like this: Early life was simple, gaining energy from non-living sources. … The first innovation was … predators and prey … competing to achieve their goals of eating, and avoiding being eaten. Movement would the evolve. … social behavior follows. … communication is necessary. … the evolution of intelligence … at some point, complex communication evolves into language.

Finally, possibly inevitably, a social and intelligent organization, with the skill of language developed complex technology. It is hard to see how any other outcome is possible. Soon, they will be building spaceships and exploring the universe – if they manage to avoid destroying themselves first. (pp.317-318)

Oh, and also some violence:

The depressing truth is that violence may be necessary for large-scale cooperation and innovation. (p.315)

So how can Kershenbaum know all this?

We just need to be careful to choose those laws of biology that are truly universal. … The first and most important law is that complex life evolves by natural selection. … This short-sightedness of natural selection actually makes our predictions about alien life much easier. (pp.6-9)

Now I estimate that we will meet expansive aliens in roughly a billion years from today, and on Earth Kershenbaum’s whole story from “first innovation” to today took less than a billion years, with his last language stage starting in the last million years. Furthermore, we have good reasons (which Kershenbaum repeats) to expect that short-sighted natural selection will no longer be relevant after the next thousand years, when most stable features will be designed and chosen:

Its not unreasonable that in 100 or 200 years, our computer systems will be effectively sentient … If, as some astrobiologists believe, alien life is like to be artificial – i.e., ‘manufacture’ – would the rules and constraints that we have discussed the last nine chapters still apply? (p.257)

So why does Kershenbaum see only human history until today as relevant, and the next many millions of years of non-natural-selection as irrelevant, to what aliens who we meet will be like? First, there are general “rules of evolution”:

On the face of it, artificial organisms seem to open up an unlimited range of possibilities for alien ecosystems. … So can we predict anything at all about what they might be like? Yes, even if natural selection isn’t operating on these creatures, some of the rules of evolution will still apply, no matter how flexible and self-designed they might be. Even super-intelligent artificial life forms are subject to the restrictions imposed on them by game theory – they would, after all, be competing against other super-intelligent organisms like themselves. And some things like mutation, and even death, can’t be limited just by being incredibly smart. (pp.286-287)

Yes, competition and decay would remain relevant. Problem is, his book talks mainly about natural selection in particular, and what that has done on Earth, but not about competition and decay in general. However, Kershenbaum has another argument, which I quote at length now because his point isn’t entirely clear to me:

Most sci-fi tales of self-replicating machines are dystopian in the extreme; well-meaning intentions to create artificial life end with exponentially growing numbers of ‘bots’ swarming over the universe, converting every planet and every star into more and more copies of themselves. Even a simple bacterium could spell the end of the universe, if it continued to grow exponentially without limit. … that pessimism is unfounded …

Other factors are at play. Resources are limited. … other creatures evolve to eat [bacteria] and an equilibrium is reached. We don’t need to worry – the universe is not going to end in bacterial slime. … In fact, there’s no indication in the night sky that any organism, biological or artificial, has spread its influence as far and wide as we might expect if they were growing exponentially like bacteria or robot crabs. …

But what if these were not bacteria but intelligent organisms, plotting a way to find new resources, ways to improve themselves, their evolutionary fitness and their ability to learn from each other and from previous generations? Could such an army of replicating artificial intelligences be possible? If so, could they be stopped? (pp.260-262)

Imagine that one day alien civilization – or perhaps our own civilization in the future – invents an artificial intelligence with capabilities greater than its creators … Some scientists and authors … have proposed that this is a genuine threat to life on Earth, and possibly to life in the universe. Others (myself included) have more faith that the more super intelligent an organism is, the less inclined it would be to destroy and dominate out of fear. (p.276)

But are we likely to encounter a planet of artificial life forms? Strangely, there is no sign that the universe has been swarmed by such super-powerful bots. … Once created, surely AI will take over the universe? Well, it hasn’t happened yet, so perhaps the risk is less than we thought. Factors such as cooperation and selfishness, and the need to navigate the tradeoff between resources and longevity, have prevented bacteria from taking over the Earth, and might prevent alien robots from taking over the universe. (pp.287-288)

Yes, bacteria have not eaten our whole planet, but life on Earth has eaten most of the biochemicals with which you can make the kinds of life on Earth. Mountains and continents mainly remain because bacteria don’t have the tech to turn those into more bacteria. So once aliens are advanced enough to travel to other planets and stars, and to make more of themselves out of them, why wouldn’t at least some of them somewhere start to do just that?

Yes, aliens eating the universe clearly hasn’t happened in a big way yet. But it is hard to argue from that both that these kinds of aliens are unlikely to ever happen in the future, and that we can be confident that we will in the future meet aliens like us today. After all, we’ve not yet seen direct sign of any kind of aliens. And even if for some reason aliens never eat the universe, how can that possibly show that they will change little in the millions of years of designed development after they reach our stage?

Kershenbaum would have been on solid ground to claim that aliens we meet will at one point will have had a history much like ours, at least up to our point and at the high abstract level. Because yes, natural selection probably does work similar on all alien worlds. I can even somewhat buy his claims that something-like-sex, predation, sociality, and language are all prerequisites for human level tech. But he goes much further, to claim that aliens we meet will be much like humans are today, with child-care, pets, and books, without having been changed much by their many millions of years of further development beyond our stage, a development much faster and more effective than natural selection. And that seems just batshit crazy to me.

I read 30 reviews of this book at Goodreads, 11 at Amazon, and every other review I could find, and none of them make this to-me-obvious point. So what does that tell you about me, or about the world?

Added 1:30p: Kershenbaum responds:

Some good points there. I don’t think you’re that much at odds with me. That’s why I confine my (much quoted) expectations of post-biological evolution to just a single chapter. But I’m a zoologist! Aren’t you *also* interested in what *non*-technological life will be like?

— Arik Kershenbaum #ZoologistsGuideToTheGalaxy (@arikkershenbaum) April 17, 2021