What Are We Looking for When Looking for Alien Life?

This post originally appeared on The Latest.

How exactly did life emerge here on Earth? Is there life anywhere else? If there is, how common is it? What kind of conditions make life possible at all? Can it only exist on a planet? An Earth-like planet?

We know much about life on Earth as it is now, and quite a few things about its past, so scientists have been able to make many educated guesses about what is possible for life to be like elsewhere. Nevertheless, we’re stuck in a difficult position where we’re missing the most important element for drawing scientific conclusions: empirical observations to test theories against.

So far, we have discovered no life out there in space. Claims of extraterrestrial life forms observed visiting us are, unfortunately, quite implausible; they can only teach us things about human psychology. (To anyone who sees reason to think otherwise, I apologize for making such a strong claim without arguing for it. I obviously have no space here to explain why this is my – and scientists’ – considered view.) All we have is the one case of life on this planet, and even here, we have a very clouded view of how exactly it began.

When looking for exoplanets that might harbor life, it makes sense to look for Earth-like conditions – to start with. We know for sure that such conditions can support life.

Yet, we mustn’t confuse this fact with the idea that life could possibly arise and thrive only in these conditions. The idea that life would have to be exactly as life is here is very interestingly criticized by biologist Jack Cohen and mathematician Ian Stewart in their book about the subject. (See also here for my review of it.)

Life on Earth evolved to thrive in the conditions that exist here. At the same time, it altered those conditions. The abundance of oxygen that allows us to breathe didn’t exist until photosynthesis emerged and that started to free it from carbon dioxide. Perhaps something like this could happen elsewhere, so it makes sense to look for planets with oxygen.

But could life emerge in entirely different kinds of conditions? Life as we know it couldn’t, but we can’t know it’s the only kind of life possible. Life is something that consumes energy to perpetuate itself; perhaps this universal pattern could emerge in something we’d never think of. All it takes for natural selection to develop proto-life into life and simple life into more complex life is the right combination of heritable characteristics, random variability, and non-random selection pressures. In principle, this could be realized by very different physical systems.

Perhaps there could be entirely foreign forms of life existing on a gas giant, or the surface of a neutron star. Of course, at this point, we simply can’t know. Science can never go out on pure extrapolation, and for all that observations show us so far, there might only be life in one place in the universe.

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Review: What Does a Martian Look Like? by Jack Cohen and Ian Stewart

what-does-a-martian-look-likeCreatures… that are born pregnant; with twenty different sexes; that eat their own children; that can survive without water for a quarter of a billion years. Absurd? Not at all.

These are creatures alive on planet Earth. And they show us just how different alien life could be from anything we know.

What does a Martian Look Like? The Science of Extraterrestrial Life (also known in other editions as Evolving the Alien) sets out to do something seemingly impossible: to scientifically describe something we have never seen. The question it asks is what we can know about extraterrestrial life. Of course, we have never found any of that. And yet, Jack Cohen and Ian Stewart also argue against imagining it will be just like life on Earth. Continue reading

6 stupid things done by natural selection

When we think of evolution, guided by natural selection, we tend to think it leads to “better” organisms. And in some sense, it often does. Forget the idea of a ladder where you always get “higher” organisms as you go up. It’s way more complicated than that. But even putting that aside, even if we just consider organisms adapting to new environments rather than becoming “better”, it seems natural selection guides things in a purposeful direction.

That does happen, but it’s easy to get the wrong impression. If you look at some feature of an organism that’s well adapted to its environment, like a monkey’s hands and tail used for climbing or a flower’s colours that attract insects, you’ll get an explanation like this: In these circumstances, it was useful for the species to have that trait, so natural selection favoured that trait and the species developed in that direction. Those who had the trait could outcompete those who didn’t, so they had more descendants, and so natural selection gave the species that trait.

It seems like this is the very basis of evolution by natural selection. Well, kind of. But it’s oversimplified. The problem is that it often leads to the reasoning “If trait A is good for survival and its alternative trait B is not, then natural selection must end up choosing trait B.” But if you ask real evolutionary biologists, there are a number of ways in which it does the opposite, and those make perfect sense once you look at the details too… Continue reading

Review: Reinventing the Sacred by Stuart Kauffman

Consider the woven integrated complexity of a living cell after 3.8 billion years of evolution. Is it more awesome to suppose that a transcendent God fashioned the cell at a stroke, or to realize the truth: the living cell evolved with no Creator, no Almighty Hand, but arose on its own, created by the evolving biosphere? The truth is much more magnificent, much more worthy of awe and wonder, than our ancient creation myths.

Reinventing the Sacred proposes a new understanding of a natural divinity based on an emerging, scientifically based world view. Complexity theorist Stuart Kauffman does not propose somehow to insert “god” into a cold, lifeless universe. Instead he argues that the qualities of divinity that we hold sacred — creativity, meaning, purposeful action — are in fact properties of the universe that can be investigated scientifically. (…)

-From the cover blurb

Reinventing the Sacred coverLast week, I reviewed Thomas Nagel’s Mind and Cosmos and criticised it for answering the human world/physical universe problem in a way that effectively rejected current science. Fittingly enough, this review features one of the books I think successfully integrates science with humanity, even spirituality.

Stuart Kauffman’s Reinventing the Sacred: A New View of Science, Reason and Religion actually has much more scientific content than one would expect from its descriptions. Certainly, it offers a view of how we could see sacredness as a property of the evolving universe rather than a god outside of it. Continue reading

Richard Dawkins on “genetic determinism”

Misleading German cover of The Selfish Gene

Dawkins mentions (p. 17) how this German cover picture for The Selfish Gene is completely missing the point.

Some time ago, a year or so back, evolutionary psychology was established as a separate subject at the University of Turku. This immediately raised controversy, at least from a few people trying to shout loudly. Some were apparently religiously motivated, but never mind them. Others were afraid of a reductionist program enforcing existing power structures by explaining them as biologically determined. That, I know, can be a real thing.

After that hassle, it was sobering to now read what Richard Dawkins had written about the myth of genetic determinism as far back as 1982 in The Extended Phenotype. Because some people still haven’t got the memo — and I’m not sure to what extent these are found among evolutionary psychologists and to what extent their critics, although in this last controversy it seemed like critics were missing the point more — I want to quote some of this to make it easily available. I will add a little commentary of my own. Continue reading

Selfish memes: How the natural selection of memes is bad for us

Genes and memes

The term meme seems to be mostly used nowadays to refer to repeated internet jokes. They are memes also, but the meaning is broader than that. The term was originally introduced by Richard Dawkins in his The Selfish Gene to denote the unit of cultural evolution, analogous to genes in biological evolution. A meme is any kind of piece of information that spreads between people —  a tune, a belief, a story, a value judgement, a news story, etc. A culture is made up of a huge number of memes. Memes are analogous to genes in that they spread, mutate and are subject to selection pressures, so that a catchy tune is more “fit” in the evolutionary sense than one that isn’t catchy.

If I’m saying memes are “selfish”, we’ll first have to explain what Dawkins meant by saying that genes are. Continue reading

xkcd Misconceptions Day 2014: Darwin’s quote on the eye

No Finnish version available.

This is the hundredth post on this weblog. Yay. Too bad I didn’t have anything more grand or celebratory.

I almost forgot, but I’m just barely in time (in my own time zone) for xkcd Misconceptions Day, inspired by this comic:

Here’s the link to the Wikipedia page for you to read at your leisure.

And below, you will find today’s semi-common misconception…

Continue reading