Blue Collar Scientist

Yesterday, Rev. Jose Gabriel Funes, the Director of the Vatican Observatory (full disclosure: the Vatican Observatory on Mt. Graham was a client of mine), was interviewed by the newspaper L’Osservatore Romano. He had some things to say about the existence of extraterrestrial life that were of interest to me.

I’m currently peddling a speech about exoplanets, in which I devote about the last fourth of the talk to the possibility of extraterrestrial life, as deduced from the current state of knowledge of exoplanets, planetary formation in proplyds, and the fairly widespread existence of molecules like amino acids and sugars in space. My verdict is that the existence extraterrestrial life is so highly probable to be virtually certain.

What I’ve learned is that fundamentalist christians really, really hate the fact that I bring up the probability of extraterrestrial life and would rather me shut up about it. I’ve not really bothered to find out why, but when Dr. Funes made his comments, I decided to do a bit of research.

Dr. Funes, who I would rate not a religious extremist¹, gets to go first:

“How can we rule out that life may have developed elsewhere?” Funes said. “Just as we consider earthly creatures as ‘a brother,’ and ’sister,’ why should we not talk about an ‘extraterrestrial brother’? It would still be part of creation.”

Ruling out the existence of aliens would be like “putting limits” on God’s creative freedom, he said.

The Bible “is not a science book,” Funes said, adding that he believes the Big Bang theory is the most “reasonable” explanation for the creation of the universe. The theory says the universe began billions of years ago in the explosion of a single, super-dense point that contained all matter.

All of this sounds fairly reasonable to me, as far as it goes. I mean, if you accept the idea of an omnipotent creating god, then you can’t with any legitimacy impose any arbitrary limitations on what he might have done in the distant past. And you certainly can’t do it from the statements of some late bronze- and iron-age guys who wrote up their impressions of this supposed god in what later became a book. It is obvious they weren’t thinking in terms of the possibility that the Earth wasn’t unique.

And it was this, combined with some of the pushback I’ve been getting from the exoplanets talk, that had me wondering why the fundies had their panties in an uproar over the issue. I found some useful explanation at the notoriously untruthful site, Answers in Genesis.

They use three basic arguments to “prove” that there can be no extraterrestrial life. And mind you, they aren’t talking about extraterrestrial intelligent life, they are ruling out pond scum and even less derived kinds of life than that. Their argument denies even a pre-DNA self-replicating form of life.

Argument one boils down to: The Earth was “designed” for life, and everything else in the universe was “designed” for other reasons.

The earth is unique. God designed the earth for life (Isaiah 45:18). The other planets have an entirely different purpose than does the earth, and thus, they are designed differently.

You would expect Isaiah 45:18 to be a pretty powerful statement on the uniqueness of life on the Earth if that is the only part of the bible they can muster to support their remarkably extremist belief. But you’d be wrong:

For thus says the LORD, who created the heavens (He is the God who formed the earth and made it, He established it and did not create it a waste place, but formed it to be inhabited), “I am the LORD, and there is none else.

How does this relate exactly? There is nothing at all about Earth being unique, let alone about life being unique. In fact, it says that god “did not create a waste place,” which strongly implies that he’s not in the habit of slapping terrestrial planets on the great heavenly pottery wheel for the purpose of leaving them lifeless and barren. The fact of the matter is that to derive the uniqueness of life from this verse, you have to read it with a strong, blinding filter of your own arrogant presupposition in place. And what does the bible have to say about doing that?

• I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues which are written in this book; and if anyone takes away from the words of the book of this prophecy, God will take away his part from the tree of life and from the holy city, which are written in this book. (Revelation 22:18-19)

• You shall not add to the word which I am commanding you, nor take away from it, that you may keep the commandments of the Lord your God which I command you. (Deuteronomy 4:2)
• Whatever I command you, you shall be careful to do; you shall not add to nor take away from it. (Deuteronomy 12:32)
• Every word of God is tested; He is a shield to those who take refuge in Him. Do not add to His words Or He will reprove you, and you will be proved a liar. (Proverbs 30:5-6)

While some of these don’t address the specific issue of imposing your own traditional beliefs on your study of scripture, the preponderance of evidence would suggest that this god doesn’t like it when people add to, or take away from, what he’s said. So it seems to me that Answers in Genesis has actually taken an anti-biblical view of the issue, which is, of course, no surprise.

The second argument is that there can’t be any extraterrestrial life because the bible doesn’t explicitly mention that it was created:

In Genesis 1 we read that God created plants on the earth on Day 3, birds to fly in the atmosphere and marine life to swim in the ocean on Day 5, and animals to inhabit the land on Day 6. Human beings were also made on Day 6 and were given dominion over the animals. But where does the Bible discuss the creation of life on the “lights in the expanse of the heavens”? There is no such description because the lights in the expanse were not designed to accommodate life…. From a biblical perspective, extraterrestrial life does not seem reasonable.

At this point you simply have to point out that plastic exists. The frozen polar caps of Earth exist. Death Valley exists. The Grand Canyon exists. Bacteria and Archaea exist. The Duck-Billed Platypus exists. Antibiotics exist. The point being that none of these things are specifically mentioned as having been created; and although you could lump some of them in with their broader classes (you might be able to smuggle the Platypus in with “animals,” for example), there are some things that have existed for a very long time that don’t fit anywhere in the Genesis description - such as the polar caps, or antibiotics.

Let’s take this a bit further. AiG’s argument is that “extraterrestrial life doesn’t exist, because Genesis doesn’t mention it.” There’s a hidden assumption in that statement, and that is that the Genesis account offers a complete, comprehensive accounting of all the things that were created. But the Genesis account itself fails to mention that it is a comprehensive account. Again, we have some dimwit, dishonest theologians bringing their own traditional beliefs into their reading of the bible and coming to wild conclusions as a result.

The third argument AiG deploys is strictly theological - that is, even more so than their vapid outgassings so far - and applies only to the possibility of extraterrestrial intelligent life. Basically, it goes like this:

1. Adam sinned. (Yes, they say Adam, not Adam and Eve.)
2. As a result, death and sin entered the world. (They cite Romans 5:12: Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned….
3. It was necessary for Jesus Christ, who was both human and god, to redeem this sin by being sacrificially killed. Killing animals couldn’t do it because they are not of the same “blood” as human beings.

Given all this - and I’ll take them at their word just for the sake of discussion, they conclude:

When we consider how the salvation plan might apply to any hypothetical extraterrestrial (but otherwise human-like) beings, we are presented with a problem. If there were Vulcans or Klingons out there, how would they be saved? They are not blood relatives of Jesus, and so Christ’s shed blood cannot pay for their sin. One might at first suppose that Christ also visited their world, lived there, and died there as well, but this is antibiblical. Christ died once for all (1 Peter 3:18; Hebrews 9:27–28, Hebrews 10:10)….

One might suppose that alien beings have never sinned, in which case they would not need to be redeemed. But then another problem emerges: they suffer the effects of sin, despite having never sinned. Adam’s sin has affected all of creation— not just mankind. Romans 8:20–22 makes it clear that the entirety of creation suffers under the bondage of corruption.

Having painted themselves into this corner, they say - hold on to your britches, this is really funny:

These kinds of issues highlight the problem of attempting to incorporate an antibiblical notion into the Christian worldview.

Hahaha! There’s two legitimate answers to this. The atheist would quite rightly say that this is a sign that your “christian worldview” is a bunch of make-believe rubbish, and maybe you should consider reality as an alternative.

The moderate religionist might point out that perhaps this is a sign that they’ve taken the “christian worldview” and pressed it a little too hard, believing it to mean something far beyond what the words were ever intended to say, and that maybe they should lay off the crack pipes for a bit.

(Moderate religionists might point this out, and they should - because whackjobs like these make them all look stupid and dishonorable - but for reasons that puzzle me, they rarely do.)

The AiG page goes on to debunk UFOs as alien spacecraft, a conclusion that I heartily endorse. Their arguments, of course, are rubbish.

Conclusion: Religionists who deny the possibility of extraterrestrial life are extremists.

1. Despite his church’s brutal views on contraception, etc - most Catholics I know freely ignore the behaviorally harmful aspects of Catholic teaching, and so I rate them more or less mainstream. In the meantime, I fully recognize the evil that the church is perpetrating against peoples in developing nations, of low income, of restricted educational opportunities, and so forth - and I condemn it. [↩]

(Update: As I said was probable, I’ve revised some parts below now that I’ve worked through some of the statistics in the paper.)

This story has been knocking around the blogosphere and the science news services (see, for example, this slightly too credulous piece on Universe Today). I had ignored it, hoping it would go away.

The basic idea is that intelligent life in the universe is rare or unique¹ - the press release argues for unique - because the evolutionary steps that are necessary to evolve intelligence are unlikely.

There’s several problems with this idea, and I see now that it isn’t going away - blogs and news services are still covering it a week after release. So it’s time for a gentle takedown.

The paper is available online. There are large differences between the paper and the press release and its treatment by news outlets and interviewers, so it is hard to know which one to address. The press release is getting far more attention, but the paper contradicts the conclusions emphasized in the release and popular press stories at several points. So I’ll deal with both.

The general thesis of the press release seems to be:

1. Stars have only so much hydrogen to burn. This limits the amount of time a planet can spend in its system’s habitable zone.
2. Complex life, and humans, arose late in the habitable period of Earth, which may have as little as another billion years to go as a hotbed of life. This suggests that evolving intelligent life is very difficult and statistically unlikely.
3. Complex life is “separated from the simplest life forms by several very unlikely steps and therefore will be much less common.”

These three premises match up very nicely to the three problems that these premises have:

1. The first premise is that life has a limited time to evolve, as determined by the lifespan of its star. The problems are these:
   • The limits placed on the lifespan of the star are not informed by astronomy. Not all stars are sun-like. Some of them have life spans much shorter than that of the Sun, but other dwarf stars² are believed to have life spans two to three times that of the sun. So while the statistical model may be appropriate for Earth, you can’t similarly limit the odds of life on extrasolar planets, because many of these systems will last longer than ours.
   • We know life can adapt to varying environmental conditions, including temperatures and pressures once thought to be impossible for life on Earth. This greatly widens our conception of what a “habitable zone” might be, which in turns increases the time that certain exoplanets will spend in those zones.
   • And finally, our conception of “habitability” might be way off. Earth has, on average, a remarkably stable climate compared to what we know about certain other exoplanets. Because of that, we have no idea how life might have adapted to unstable climatic conditions in other solar systems. It is hard to even define what a “habitable zone” in an alien life-bearing planet might be - while there are some fundamental limits at which Earth-like biochemistry simply can’t work, life on Earth doesn’t use all possible amino acids or proteins, and hasn’t adapted all possible ways of ‘hardening’ such systems to deleterious conditions. Life arising on another planet seems likely to solve these problems right away. So our definition of “habitable” might have very little applicability to the biology of another planet.
2. The second premise is that complex life, and humans, arose late in the habitable period of Earth, which may have only a billion years to go as a life supporting planet. This therefore suggests that evolving complex life is difficult and unlikely - otherwise it would have happened sooner. The problem is this:
   • While it may be true that Earth is late in its habitable period, we are dealing with a sample size of one. We don’t know if Earth was, for some reason³ a “late bloomer,” or if we shot out of the starting gate at enormous speed. A sample size of one is useless - but having said that, it is more reasonable to suppose that Earth is closer to the average than a statistical edge case - because by definition, the average is more probable. That suggests that the evolution of complex, intelligent life in multiple trials would happen in more and less than 4.5 billion years, and that the peak would be somewhere around 4.5 billion years. But remember - this is a useless sample size - I’m just speculating. The point, though, is this: Given a star with a solar lifespan, or longer, the logic that Watson uses to justify his opinion of the rarity of intelligent life breaks down. It actually shows that intelligent life is fairly likely on such planets.
3. The third premise is that complex life is “separated from the simplest life forms by several very unlikely steps and therefore will be much less common.” The problems are these:
   • We don’t actually know that complex life is “separated from the simplest life forms by several very unlikely steps.” Nobody has done any experiments to explore the odds of the various evolutionary steps that Watson mentions. Nobody has explored the statistical probability of the origin of cellularity, or of cellular specialization, two evolutionary steps that Watson cites as being rare.
   • One evolutionary step that the press release cites as rare is the evolution of multicellularity. This strikes me as false. Evolution in the lab has shown that single-celled organisms tend to colonize pretty readily, suggesting that step at least is not unlikely. And Watson points out in the paper, “…the formation of colonies from individuals seems definitely to have occurred more than once in the history of life, and can be excluded on those grounds [as being highly probable, and not rare like the others]….” So here there is a contradiction between paper and press release here.

The problems go deeper, however. Watson’s supposedly necessary evolutionary steps might be appropriate for evolving Earth-like intelligent life, but it isn’t clear to me they are inherently necessary for all intelligent life. From the press release:

Prof Watson suggests the number of evolutionary steps needed to create intelligent life, in the case of humans, is four. These probably include the emergence of single-celled bacteria, complex cells, specialized cells allowing complex life forms, and intelligent life with an established language.

Why do we need bacteria as a step in this chain? Why can’t nucleation come first, and then a secondary membrane evolve later to protect (or render captive?) the nucleus and the materials and organelles it depends on, thus bypassing bacteria-like organisms entirely? I don’t claim to know all the different ways that we can get from replicating molecules to prokaryotic cells, but I think it is a failure of imagination to presume that something like a bacterium is a necessary step in the evolution of prokaryotic cells, and onward to intelligence.⁴ Failure of imagination is going to be a recurring theme from here on out.

Similarly, do we need cellular specialization for intelligence? I grant it is hard to see how it could be otherwise, given our understanding of terrestrial biology. But is this really the only way to go about it? This requirement is presumed, not defended, and I’m not familiar with literature that defends it as a universal (as opposed to Earthly) requirement for intelligent life.

And finally, the press release says the evolution of language is a necessary step. So what about language? I’m not a linguistic specialist, so I went looking for a definition. Wikipedia offers the following⁵:

A language is a system of visual, auditory, or tactile symbols of communication and the rules used to manipulate them.

Visual, auditory, or tactile…. That corresponds to the senses of vision, hearing, and touch, but I have a problem with limiting things that narrowly. I can imagine, even if Watson cannot⁶, an intelligent species conducting complex abstract communication chemically. I can also imagine it being done with sensory organs (and hence senses) not represented on Earth. I can also imagine it being done through what humans might consider direct neuro-anatomical contact.

Again, there is a failure of imagination here - I’m not saying any of these methods I speculate about are probable, but it seems like they might be possible, and there are surely more ideas out there than I’m able to come up with in five minutes of thinking about the problem. To be fair, the obsession with language belongs to the press release, not the paper⁷. We should probably just replace “language” with “communication method.” But whatever word you use, the language issue is a problem for Watson’s hypothesis. Every time we think up a possible method of communication, linguistic or not, we’re increasing the opportunities for life forms to evolve a communication method necessary for becoming an intelligent species by Watson’s criteria.

In other words, whatever odds Watson settled on for the evolution of intelligence, they are too low, because he only seriously explores an Earth-like way of evolving an Earth-like intelligent species.

Moving on, what I’m not seeing in either the press release or the paper is any discussion of the definition of intelligence. I think we’ve had a lot of intelligent life on Earth, and in widely separated taxa, as well. I own a parrot - it superficially appears to be at least as intelligent about physics and interpersonal relationships as a human three year old⁸. I’m told that porpoises and most other cetaceans are far from stupid. I’ve seen amazingly intelligent cooperative behavior among ravens in Alaska that I might post about someday. And I’m not sure that we’ve really come up with a good definition of the term “intelligence,” nor are we good at recognizing its existence in other species, even when we are familiar with them.

I think what Watson is after is intelligent and technological species. I’ll grant that my parrot is only barely technological (he knows how to use a few simple tools for single tasks), and the rest of my examples apparently not at all technological. But they are intelligent. If you need to evolve from intelligent to technological, and you offer some odds on that happening, we can all see that those odds went through multiple trials on Earth. Parrots had their chance and didn’t make it, cetaceans had their chance and didn’t make it, chimps had their chance and almost made it but not quite, ravens had their chance, Velociraptor probably had its chance - and each time, there’s a certain percent chance of intelligence going technological.

This is another flaw in the hypothesis. The paper evaluates only the evolution from primate to human societies, which I am interpreting as evolution from intelligent to technological societies. The paper recognizes that on Earth there was only one chance of this happening, and that it had to happen among primates. But looking around, it seems to me there were a bunch of chances for this transition to evolve, and that it happened to occur in primates. There wasn’t just one roll of the dice. This would drive down the probability of any given species making evolving technology, but would seem to increase the probability that technology would arise sooner or later, since there are so many different taxa it could have evolved from.

But remember - our sample size is one. It isn’t big enough to draw conclusions from. I’m merely trying to show that the data we have to had can be used to support different conclusions from Watson’s.

Finally, one more objection - and I think a real, genuine objection, and one that is fatal to the hypothesis. From the press release:

His model, published in the journal Astrobiology, suggests an upper limit for the probability of each step occurring is 10 per cent or less, so the chances of intelligent life emerging is low – less than 0.01 per cent over four billion years.

Interesting - he’s saying that the combined odds of all the necessary steps to producing intelligent life actually happening are less than one hundredth of one percent.

Astronomers have recently determined that rocky planets are very common in the local universe. According to these results, at least 20%, and possibly as many as 60%, of sun-like stars have rocky planets.⁹ There are about 100 billion stars in the Milky Way, 10 billion of which are like the Sun. We’ll adopt the worst-case scenario from the study and say that only 20% of them have rocky planets. We’ll further assume that rocky planets are the only kind that can support technological life, and we’ll completely ignore the frequency of rocky moons orbiting “hot Jupiter” exoplanets, which is likely to bring the number of available bodies way up.

That leaves 2 billion suitable planets in the Milky Way. Watson says the chances of intelligent life evolving are less than 0.01 percent. Fine - multiply 2 billion times 0.0001 to give you the maximum number of planets that should have intelligent life, and what do you get?

Two hundred thousand.

Wow - 200,000 planets in the Milky Way alone that support intelligent life? That’s amazing. There’s some limitations on this number, however:

• Some of those planets are not going to be in the habitable zone.
• Some are going to have other problems seemingly prejudicial to the development of life.
• Only about half this number are currently 4 billion years old or older.

However, even after taking a few bites out of this huge, juicy apple, we’re going to have a lot of apple left. This should be enough to show that Watson’s cumulative odds are going to have to be considerably smaller than 0.01% if he’s going to make intelligent life unique, or vanishingly rare. As it stands, Watson’s odds for intelligent life are so incredibly high that he has utterly failed to explain the Fermi Paradox - which the paper mentions by name and apparently seeks to explain.

Look at it this way - if he’s off by an entire order of magnitude, there’s still 20,000 planets in the bin. His odds have to be six orders of magnitude off just to get the number of other planets with intelligent life in the Milky Way below one.

And that’s just in this galaxy. Extend that to the universe, and you’ve got major problems coming up with an expression of probability low enough to make Earth special in this way.

Watson is an environmental scientist, not an astronomer, so he can be forgiven for not understanding the large numbers involved here. However, perhaps we might gently suggest he include an astronomer on the research team? Or at least consult with one before writing the press release? Dare I say that he’s made the same mistake that evolution deniers make - just as they do not understand the vast amounts of time and the huge numbers of individuals through which evolution has had a chance to work, Watson does not seem to understand that the number of stars with suitable exoplanets can only be described by a gargantuan, unimaginably huge number.

Personally, I find 200,000 planets with intelligent life to be incredibly optimistic, so I’d really be more comfortable if his odds were way lower. But then, we have no reliable data here - it’s almost all speculation.

But the problem ultimately doesn’t go away - there are so many rocky planets (according to our population statistics) orbiting Sun-like stars in the universe that I have no way of grappling with numbers that big.¹⁰ Ultimately, I don’t find Watson’s ideas compelling for these contradictory reasons: his odds of evolving intelligent life are way too high; his conclusions about the uniqueness or rarity of intelligence are contradicted by back of the envelope calculations; and the number of candidate planets is so high that given any reasonable set of odds, intelligent life still looks highly probable.

1. And I’ll say clearly that this sounds like the PR officer or press “spin” on an otherwise much more deeply significant paper. [↩]
2. The sun is a large-ish yellow dwarf. [↩]
3. Or no reason - or purely random reasons. [↩]
4. Watson says “probably” - so I don’t want to push too hard. [↩]
5. And it was pretty much in line with the other definitions I read. [↩]
6. Or merely did not. [↩]
7. The paper uses the word “language” only once. For this evolutionary step, the paper refers to the transition between primate societies to human societies. That seems much more appropriate, if broader and less well defined - I find that human society has a lot in common with primate societies. [↩]
8. Admittedly, it doesn’t seem to grasp English as well as the average three-year old. [↩]
9. This assumes a galactic metallicity similar to that of the Milky Way - it wouldn’t necessarily hold for very distant galaxies that were full of first-generation stars. [↩]
10. Yes, I understand scientific notation - it’s just that there are so many galaxies, with so many stars, that it all becomes rather meaningless after a while. [↩]

Tonight at seven I’ll be giving the astronomy program at the Eagle River Nature Center - out at the end of Eagle River Road in, ummm, Eagle River, of all places. I’ll be talking about exoplanets, and the prospects for life elsewhere in the universe. I mentioned this event earlier this week, but to tell you the truth, I wrote that posting a few months ago when I was first booked for the date, and before I had completed the program. It was scheduled to just appear at the right time thanks to the complexities of Wordpress’ future posting features.

So a more accurate description of the content can be found here, and some post-program coverage, including a link to a review, can be found here. But if you read this stuff, be aware, I’m not at CCSC tonight - I’m at the Eagle River Nature Center at 7:00 PM. See ya there!

Just a friendly reminder that you can hear my talk about exoplanets - planets in orbit around other stars - tonight (Thursday, March 13) at the Campbell Creek Science Center in Anchorage. Check here for details.

I’m going to talk about the history of exoplanets - including ancient speculation and the sad fate of Giordano Bruno - the state of knowledge about exoplanets today, information about how exoplanets form, and at the end a whirlwind explanation of why I think life must exist elsewhere in the universe. I promise it won’t be boring. Come on out and see the show!