Not your mom and dad’s evolution: the failure of natural selection

If I asked you what drives evolution, what are the first things that come to mind? If you are like me, it is mutation and natural selection. That is what we are taught in school and that is what we read about on the popular level and hear in most popular-level discussions. Now, what if I told you that prominent evolutionary biologists dissent from this view, or at least significantly modify it. We will explore a case of this dissent in this blog post.

A while back I was interested to revisit the arguments for Intelligent Design (ID) and was led down an alternate path. Out of all the ID arguments out there, one that strikes me as particularly difficult and nagging is the problem of generating new biological information. This can be stated as: natural selection tells us how genes survive, but not how they arrive. How do genes and phenotypes arrive on the scene? Again, if you are anything like me, you’ve heard it so many times that it is the mantra we all adhere to: microevolution working on an epochal timescale equals macroevolution. That’s it. But, this time I began wondering if this assertion is really plausible. We now have tools to examine the plausibility thanks to the molecular revolution.

From my own searches I could find virtually nothing that directly addresses this question, so I decided to seek out the most qualified scientists and read their material on the subject. That is when I learned about Michael Lynch, an emeritus professor, member of the Academy, and author of a textbook on population genetics. We will be examining select arguments from Lynch’s paper, “The Frailty of Adaptive Hypotheses for the Origins of Organismal Complexity”. (1) From the outset Lynch sets up the problem that at its core is ID’s nagging question, where does new genetic information come from? This is considered in terms of genomic complexity and finally organismal complexity as the title states. Early on in a moment of polemical gold he states:

It has long been known that natural selection is just one of several mechanisms of evolutionary change, but the myth that all of evolution can be explained by adaptation continues to be perpetuated by our continued homage to [Charles] Darwin’s treatise in the popular literature. For example, [Richard] Dawkin’s agenda to spread the word on the awesome power of natural selection has been quite successful, but it has come at the expense of reference to any other mechanisms. . .

He goes on to explain that there are four primary forces of evolution: natural selection, mutation, genetic drift, and recombination. Only the first is adaptive, therefore the remaining forces are nonadaptive.

Lynch frequently utilizes differences between prokaryotes and eukaryotes to understand the origin of complexity, so we will review these briefly. Let’s start with morphologic differences. Prokaryotes are unicellular organisms that are relatively small, lack a nuclear membrane, have a capsule, and flagellum for motility. Think bacteria. Next, eukaryotes can be unicellular (yeast) or multicellular (animals) and have relatively larger cells, nuclear membrane present, usually no capsule, and no flagellum. In multicellular organisms, cells differentiate to take on specific functions such as nervous tissue, muscle, connective tissue, absorptive epithelium in the gut, endocrine cells, and so on. Notice that morphologically eukaryotes can be vastly more complex. Prokaryotes represent an earlier phase in evolutionary history compared to eukaryotes, thus complexity developed over evolutionary history leading to our modern biosphere. This complexity is mirrored on the genomic level. Eukaryotic genomes contain an abundance of mobile elements, genes with multiple introns, multiple transcription-factor binding sites, preservation of gene duplications, and genes which are transcribed into units with untranslated flank sequences (i.e., poly A tail). Prokaryotic genomes do not contain any of these thus are streamlined by comparison, and this is main point you should get from this.

Recall the Central Dogma of Biology: biological information flows from gene to phenotype and the starting point is the gene. This means that if we understand the origins of genomic complexity (i.e. from prokaryotes to eukaryotes), we understand the origins of complexity on other levels of biological organization such as morphology, multicellularity, size, function, and so on. This is what the molecular revolution affords us. So, the central question is, what evolutionary forces are primarily responsible for producing complexity?

Lynch argues for the “passive emergence of genome complexity by nonadaptive processes”. That is a mouthful, so take a minute to digest each term. Passive meaning no one is tampering with it (i.e., no intelligent agent). Nonadaptive processes meaning mutation, genetic drift, and recombination as opposed to the adaptive process of natural selection. Alright folks, here is the bad news. The bad news is Lynch’s argument hinges on population genetic theory which is a bit technical. I am not going to derive population genetic theory here, however suffice it to say that nonadaptive processes predominate (over natural selection) when 2Ngs << 1 where Ng is the effective population size and s is the fractional selection advantage. This is also called the “criterion for effective neutrality” with neutrality referring to nonadaptive and non-deleterious. Further substituting in the equation, s = nu where n is number of nucleotides to be conserved for proper gene function and u is the mutation rate per nucleotide site. Notice that as s increases so does (they are directly proportional), which means that each adaptive embellishment comes with the cost of maintaining the fidelity of more nucleotides. This is called mutation hazard. Using population genetic data to calculate real numbers for the criterion for effective neutrality, we find that:

. . . an embellishment that increases the mutational target size of a vertebrate by n<250 will be largely immune from selection, and hence free to drift to fixation, whereas the critical value of n for a prokaryote is << 10.

In simplified terms, vertebrates have a markedly easier time increasing the complexity of their genome without mutational hazard whereas prokaryotes have a difficult time. Recall the differences in complexity between prokaryote and eukaryote genomes. The criterion of neutrality provides a powerful explanation for the observed differences. The differences are explained by neutral or nonadaptive increases in complexity. This, in a nutshell, is Lynch’s argument for the passive emergence of genome complexity by nonadaptive processes.

Lynch points out that even if one was not convinced that complexity primarily emerges from nonadaptive processes, these provide the null hypothesis. I find this interesting, and wonder how to go about establishing this from a philosophy of science point of view. Should the null hypothesis be totally random nonadaptive evolution and the adaptationists shoulder the burden of proof, or something else? (If anyone has an insight or has studied the philosophy of science, please indulge us). Lynch also points out frequently that there is no direct evidence for adaptive hypotheses. This makes his case stronger.

Lynch’s paper has a frustrated tone that suggests a broad failure of engagement with data and arguments for nonadaptive evolution. For example:

Most biologists are so convinced that all aspects of biodiversity arise from adaptive processes that virtually no attention is given to. . . neutral evolution, despite the availability of methods to do so. Such religious adherence to the adaptationist paradigm has been criticized as being devoid of intellectual merit [citing a paper by Stephen Jay Gould and Richard Lewontin].

And poignantly,

The hypothesis that expansions in the complexity of the genomic architecture are largely driven by nonadaptive evolutionary forces is capable of explaining a wide range of previously disconnected observations. . . This theory may be viewed as overly simplistic. However, simply making the counterclaim that natural selection is all-powerful (without any direct evidence) is not much different from invoking an intelligent designer (without any direct evidence).

There are likely to be scientists who understand these arguments and know the data yet disagree. However, there are also probably scientists who simply avoid mathematical theories, as biologists are infamous for. And, there are also scientists whose careers or reputations hang on the power of natural selection, so they have motivations to dismiss or sidestep engagement. What Lynch seems to press in this paper is more serious and objective engagement.

Let us revisit ID’s nagging question: how is new biological information introduced? Is this plausible? It seems the answer is, complexity accrues primarily through nonadaptive forces which is also called neutral evolution. When neutral evolution was first worked out in the 80’s Kimura coined the term “survival of the luckiest” to counter adaptationist’s term “survival of the fittest”. (2) And, this is where I ask my dear readers:

How lucky are we?

Sources

1) Lynch M. “The frailty of adaptive hypotheses for the origins of organismal complexity.” Proc Natl Acad Sci USA. 2007 May 17;104 Suppl 1:8597-604. Free full text.

2) Kimura M. “The neutral theory of molecular evolution and the world view of the neutralists.” Genome. 1989;31(1):24-31. PMID: 2687096.

House of probability: a puzzle

This post will start with a puzzle of sorts which is not supposed to be difficult but rather thought-provoking. Enjoy!

Room 1

You are led into a room with 5 bins. Inside each bin are playpen balls. Each bin contains a single ball color – red, orange, yellow, green, or blue. You are instructed to take a black bag and place inside it exactly 200 red, 30 orange, 25 yellow, 20 green, and 2 blue balls. You follow through with these instructions. Then, you are instructed to stir and mix up the balls. Finally, you are instructed to reach in blindly and pick a single ball at random.

What color ball are you most likely to pick? What color ball are you least likely to pick?

Room 2

You are now led into a second room through a door. There you find a tied-up black bag. You are given the following information:

  • The black bag contains playpen balls.
  • There are multiple ball colors.
  • There are differing amounts of each ball color.
  • The balls have been mixed up.
  • (In other words, it was premade in a similar manner to room 1 but may have different colors and amounts).

You are then instructed to reach in blindly and pick a single ball at random. You come up with a purple ball.

Is the purple ball likely to be the most common color? Is it likely to be the rarest color?

Room 3

You are now led into a third room through a door. There you find a tied-up black bag. You are given the following information:

  • The black bag contains playpen balls.
  • There are multiple ball colors.
  • There are differing amounts of each ball color.
  • The balls have been mixed up.
  • (In other words, it was premade in a similar manner to room 1 but may have different colors and amounts).

You are instructed to empty the bag of balls on the floor and pick your favorite color. This happens to be seafoam green.

Is the seafoam green ball, your very favorite color, likely to be the most common color? Is it likely to be the rarest color?

Room 4

You are now led into a fourth room through a door. There you find a tied-up black bag. Also, surprisingly, sitting on the floor in a golden playpen ball. You are given the following information:

  • The black bag contains playpen balls.
  • There are multiple ball colors.
  • There are differing amounts of each ball color.
  • The balls have been mixed up.
  • (In other words, it was premade in a similar manner to room 1 but may have different colors and amounts).
  • Also, the golden ball came from inside the bag.

Is the golden ball likely to be the most common color? Is it likely to be the rarest color?

Room 5

You are now led into a fifth room through a long, dark hallway. Please, sit down in this comfortable chair. This is where everything will be explained to you. In room 1 you know the most common and rarest color in the bag because you actually counted out the balls and placed them in the bag. Therefore, your random selection will likely be the most common color, red. In room 2, however, the bag of balls was premade. Since you drew at random, you would expect statistically that whatever you draw will be the most common color. Therefore, you can infer that the purple is the most common color in this bag. In room 3 you picked your favorite color. Well, this is not random! Therefore, you cannot make any sort of inference about how common seafoam green balls are in this bag. Finally, in room 4 the bag is premade and a golden ball has already been selected. Herein lies the problem to answering the questions posed. You do not know how the golden ball was selected, whether randomly or someone’s favorite color or some other method.

All of these lessons show us that in order to make the statistical inference that the sample is likely to be a common type, it must be known to be a random sample. This is absolutely central. What is this exercise relevant to? Well, the Earth is our sampled life-producing ball, and the universe is a black bag full of other balls. Is the Earth a random sample? The insurmountable problem is that from our perspective we simply do not know if the Earth is a random sample. It’s like we walked through the door (i.e., became conscious as a species during evolution) and there is a golden ball and we look up at the starry sky which is a black bag full of unknown colors. Our situation is room 4. We cannot say whether the life-producing planets are common or rare because we do not know if we are a random sample or not.

What is this arguing against? Ultimately, it is arguing against the Principle of Mediocrity (PoM). More specifically, a version of the PoM which is statistical in nature, which IMO is the only PoM that really matters. The PoM states that humans represent a random sample, therefore are likely to be common. The problem with this is that we do not know if we are a random sample. We did not draw humans out of a black bag randomly, so how can we possibly know if we are a random sample? It’s not enough to just assert that we are a random sample, rather we need to prove this. There needs to be reasons and evidence. Just like if you walked into room 4, you would have to prove that the golden ball was randomly selected before you could make the statistical inference.

Some reasons that might be given are the discovery of earthlike exoplanets using the Kepler Space Telescope. However, the Rare Earth Hypothesis pushes against this by saying that the number of coincidences required to evolve from abiogenesis to intelligent species are statistically improbable despite earthlike planets being relatively common.

There is another version of the PoM that seems to be the more common one on the internets. This one irreverently states that humans are mediocre chemical scum on a piece of dirt in a meaningless sea of universes in an abyss of nothingness that came from nothingness. This version, which I have caricatured here, I like to call the value-based PoM. It’s aimed at saying that the physical configuration of humans and earth is basically no more or less valuable than any other physical configuration. Its proponents probably don’t even realize that they are preaching amoralism. There’s a reason why I don’t hesitate to push my lawn mower over crawling insects yet I would never push my lawn mower over crawling infants. I value little humans more than mosquitoes. You can hammer a nail into wood but you would never hammer a nail into your spouse. I don’t think they would disagree, so I think their statements stem from a misunderstanding of the statistical PoM. I think they really believe the statistical PoM without realizing that they are merely asserting we are a random sample without justification and then apply our alleged commonality to the idea of value thereby allowing them to formulate cheeky, controversial statements which are metaphysically loaded and contradictory to secular humanism and all other humanisms. /rant over

Another argument I found for the PoM is put forth by famous cosmologist, Alexander Vilenkin:

Actually, I am surprised that this issue is so controversial, since one can easily convince oneself that the Principle of Mediocrity provides a winning betting strategy. (1)

He goes on to give an example: You show up to a scientific meeting in which everyone is wearing colored hats and there are no mirrors in the room so you do not know what color hat you are wearing. You count 80% white hats and 20% black hats. If you have to bet on what color your hat is, you should bet on white, because you should assume that you are randomly selected.

Vilenkin is correct! But, his scenario does not reflect our situation at all. His scenario is closest to room 1 in this blog post puzzle. If I were to make some corrections to his analogy, it would look like the following. You show up to a scientific meeting and are blindfolded. A hat is placed on your head. You are told that everyone else has hats as well. You are told that your hat is seafoam green. You are still blindfolded and asked if you think anyone else has a seafoam green hat. Should you assume you are a random sample? In this more accurate scenario, there is no winning betting strategy precisely because of a lack of appropriate information. For example, if the hatter had told you that your hat was randomly selected, then you could make the inference. Knowing that what we are looking for is a random sample it crucial to making the statistical inference of the PoM, and this information is simply not available to us.

In conclusion, if we are asked if humans are mediocre and common OR exceptional and rare, I think the response is that we don’t know. Based on scientific data we still don’t know. Based on statistical inferences we still don’t know. This means to get anywhere we should start with new science. Only with new discoveries can we get closer to knowing how common or rare Earth actually is.

(1) “Principle of Mediocrity” by Alexander Vilenkin, published on Arxiv 2011.

We are alone in the universe (part 2)

You are probably wondering what evidence one could possibly be brought to the table that would suggest that we are alone. If you are wondering this, you are in the right place. Get ready to rumble.

From part 1 we learned that the Principle of Mediocrity suggests that the frequency of complex earth-like life is an indicator for the frequency of intelligent life regardless of how exotic extraterrestrial life ends up being. This is because humans are much more likely to be an easy way to evolve intelligent life rather than a difficult way. We are not special like a snowflake; we are mediocre. But, that’s OK. Actually, that’s a good thing for this analysis.

The central question now is: what do we think is the frequency of complex earth-like life? The general feeling of space enthusiasts is that our universe teeming with microbes and with intelligent civilizations popping up a few times per galaxy or so. Feelings and guesses are fine and dandy, but there is a more reasoned approach that has concluded that earth-like complex life is incredibly rare. This is the Rare Earth Hypothesis. The analysis goes like this: we can see to produce complex life and intelligent life on Earth, several factors were important including:

  1. Galactic habitable zone – not too close to the central black holes which emit gamma radiation, not too dense region of stars which poses danger of supernova and gravitational perturbations
  2. Favorable star – must have adequate lifespan for evolution
  3. Planet in Goldilocks zone – allows for liquid water
  4. Good Jupiter – protects from asteroid impacts (Bad Jupiter refers to a gas giant in a closer orbit to the sun than the earth and would cause detrimental gravitation perturbations)
  5. Stable orbit – for climate stability
  6. Planet composition – need solid surface in addition to oceans of water
  7. Plate tectonics – for carbon cycling and greenhouse effect
  8. Magnetosphere – protects from harmful radiation
  9. Billions of years of stable climate – don’t freeze or have runaway greenhouse effect, just look at Mars and Venus to see what could have happened to Earth
  10. Abiogenesis (or panspermia?)
  11. Abiogenesis occurs early in planetary life
  12. Not too many mass extinctions
  13. Other factors

Any individual factor is not likely rare in itself (except the factors which must stay true over long time periods). For example, we know extrasolar planets are not rare. Statistically every star has at least one planet. Also, planets in the Goldilocks zone are not rare. According to Kepler Space Telescope data around 20% of stars have rocky planets in the Goldilocks zone.

The lesson we learn here is that it’s not that individual factors are rare, it’s that the combination of factors is rare. It’s like rolling a cosmic dice over and over and having to get the right combination of numbers by chance. Chance and coincidence are at work here. There are 12 factors listed above, but how many factors are there really? There could be far more, but we don’t know for sure. Furthermore, we don’t know the frequency of each of these factors yet.

Let’s perform some calculations to get a feel for how chance will affect the frequency of complex earth-like life. Looking out at the observable universe there are about 100 billion galaxies each with about 100 billion stars. That means there are 10^22 stars in the observable universe! Now, let’s make some assumptions for the sake of analysis. Let’s assume there is one planet per star. Let’s further assume there are 22 individual planetary factors (like the 12 listed above) necessary for complex life and each factor has a 10% chance of occurring. How many planets will harbor complex earth-like life? With these assumptions, only one single planet in the whole observable universe will! What if we increase the average frequencies of the factors to 20%? There will be just over 4 million planets with complex earth-like life which is far less than one per galaxy. What if we increase the number of planetary factors to 400, what would the average frequency need to be for just 2 planets with intelligent life? About 88%. Doing these calculations is constrained by our starting assumptions, but this exercise is helpful because it shows us how the universal lottery may require substantial luck just for a few planets in the observable universe with complex earth-like life.

The thing that pushed me over the edge in this discussion is the factors which must remain true over very long time periods. Complex life is very fragile and that is evidenced by the extinction of so many species. How many dinosaurs have you seen today? If you go to the Creation Museum then Adam and Eve walked alongside dinosaurs, but the fossil record completely fails to support this. The dinosaurs were wiped out during a mass extinction event around 65 million years ago partly caused by a 10 km diameter asteroid slamming into the Earth causing severe climate change. About 50,000 years ago there occurred a similar event called the Toba catastrophe theory which nearly wiped out all of humanity. It is thought that the human population was reduced to around 6,000-10,000 individuals! How lucky are we to have persisted? These kinds of extinction events are common in the fossil record, and even more interesting may help accelerate evolution by opening up niches. Evolving complex life may require a delicate balance of extinction and speciation. But, how often does a delicate balance happen by chance in the universe?

Astrobiologist, David Waltham thinks that the most lucky feature of our planet is its 4 billion years of climate stability. Think about our neighboring planets who probably started out with compositions similar to that of Earth. Due to the sun’s gradual increasing solar output and a runaway greenhouse effect, the surface of Venus is more than 400 C, far too hot for earthly life of any sort. Even extremophiles would find this to be hell. And, Mars once had oceans of water and possibly life, but now is a freezing desert and bombarded with lethal doses of radiation. It may have pockets of microbial life, but certainly nothing complex like on Earth. We are lucky to have enjoyed such climactic stability.

How often does abiogenesis occur? How often do earth-like planets fail to produce complex life from simply life? How often on earth-like planets does extinction events set back evolutionary progress? How often does a planet enjoy 4 billion years of climate stability? If your answer is, “Not very often” then you might be a proponent of the Rare Earth Hypothesis.

We are alone in the universe (part 1)

Suppose there are many different ways for the universe or multiverse to evolve intelligent life. There will be easy ways to evolve intelligence and difficult ways, and these ways will fall on a spectrum as such. In fact, it is reasonable to suppose that this spectrum can be plotted as a frequency distribution and will be a bell-shaped curve. Where would humans fall on this curve?

Before answering this let’s pay homage to the debate of the Anthropic Principle. This principle states that the universe is geared towards producing us. It is derided by modern scientists because it seems like cosmic hubris. Since the time of Copernicus, we have been moving away from this thinking starting with the heliocentric model of the solar system. In keeping with this trend the latest proposal is the multiverse which solves the problem of fine-tuning of physical constants. This change in thinking is called the Copernican Principle, or Principle of Mediocrity, and would suggest that we are most likely an average way to make intelligent life. We are not found at the tail ends of the bell curve, rather smack in the middle. Earth-like biology is probably a rather easy way to make intelligent life in this universe/multiverse. Applying the Principle of Mediocrity, the frequency of earth-like complex life, is a surrogate marker for the frequency of intelligent life in the universe. That is very important because we can actually say something about the possibility of earth-like life out there. What does science say? How difficult is it to make earth-like life?

If you think we are in an infinite multiverse where all possibilities become actualities, then this question might be of less importance to you. Because even if it’s one in a zillion zillion, there ought to be an infinite number of earths out there in the multiverse. This is theoretical physicist Brian Green’s take on the matter. There is another Naïve Thinker out there but who is actually the President of Mars, but this doppelganger must be almost infinitely far away. If you are going to be this generous with reality, you will run into a problem. If absolutely everything possible is actualized, then God must exist. And, an all-powerful being would also be God of the whole multiverse. Also, the Flying Spagetti Monster would exist, but God would eat it for lunch. Alright, alright come back down to reality now! This escapade proves the point that we should not be too generous. Such bizarre notions of the possible do not respect the elegant universe we can actually observe, and it’s not a multiverse. . . yet. And, if we eventually find we are in a multiverse, it will not necessarily be infinite. How could we even prove that it is infinite?

Barring an infinite multiverse which I think is reasonable, how difficult is it to make earth-like complex life? We will address this in more detail in part 2.

The Gaia Hypothesis and Extraterrestrial Life

We are now in the Golden Age of exoplanet science. The Kepler Space Telescope has tantalized us with data showing a rich diversity of exoplanets including the discovery of Kepler-186f which orbits in the habitable zone of its sun and has a radius comparable to the Earth. Kepler-186f is the best Earth-analog we have discovered as of September 2014, and probably just the tip of the iceberg of what is out there. Does life exist outside of our solar system? This blog post examines the possibility of intelligent life existing outside of our solar system focusing on the factor of climate stability. It was first inspired when I read the book Lucky Planet by David Waltham which I would recommend for anyone interested in this subject.

Defining the problem

According to the Solar Standard Model, the sun has dramatically evolved over the course of its lifetime. If we could measure the solar output 4 billion years ago, we would find the output to be about 30% less than today. Around this time liquid water emerged on the surface of the Earth. We have evidence of liquid water on Earth as early as 3.8 billion years ago and hints of life date to as early as 3.5 billion years ago. The question is: how could a 30% dimmer sun coincide with an ocean on the Earth? This question was first asked by astronomers Carl Sagan and George Mullen in 1972 and has been dubbed the “faint young sun paradox”. Before addressing this let’s dig a bit deeper.

Since life began billions of years ago we know that liquid water had to exist on Earth. In fact, the Earth has enjoyed a remarkably stable climate to have continuous liquid water and complex life. The geological temperature record shows the global temperature has remained at 15 plus or minus 10 degrees C over the past 500 million years and with an overall cooling trend. The general explanation given by scientists is that the Earth started with a stronger greenhouse effect which compensated for a dimmer sun. Over time the sun became brighter (following the main sequence for stars) and geological and/or biological processes decreased the greenhouse effect and this cancellation led to a relatively stable climate. But, why did it happen this way?

When thinking about an explanation of the Earth’s remarkable climate stability, there seems to be only two games in town: the Gaia hypothesis or blind luck. We will try to differentiate between these possibilities. The Gaia hypothesis was first proposed by James Lovelock and has been debated by the scientific community ever since. Heavyweights like Richard Dawkins and Stephen J Gould have argued against Gaia. We are left with a nuanced discussion. For our purposes the Gaia hypothesis will be stated as: the biosphere interacts with the environment in such a way to promote a stable climate. This is accomplished unconsciously by climate sensing and feedback systems that exist within the biosphere. There are many criticisms of Gaia, but I want to focus on one that I find particularly convincing.

The Great Oxygenation Event is evidence against Gaia

Several billion years ago the Earth’s atmosphere was largely composed of nitrogen, carbon dioxide, and methane. Then, life evolved photosynthesis which introduced oxygen into the environment. It is thought that oxygen initially reacted with minerals which prevented it from building up significantly in the atmosphere for several million years. Eventually oxygen levels built up in the atmosphere which is called the Great Oxygenation Event. What was the consequence of this atmospheric change? Oxygen chemically reacts with methane and eliminates it. Methane’s greenhouse effect is 30X as potent as carbon dioxide. Since photosynthesis both removed carbon dioxide and eliminated methane, it greatly reduced the greenhouse effect and led to global cooling. Eventually ice at the poles advanced toward the equator and a period of global glatiation began, the Huronian glatiation. We have evidence that the entire Earth was frozen in what is called the Snowball Earth! Almost all life became extinct, but some pockets of life survived. Photosynthetic organisms could have survived under several meters of transparent ice at the equator. Also, ecosystems relying on volcanic vents in the ocean could have survived. What seems to have rescued the Earth from the snowball conditions is volcanism and possibly asteroid impacts which reintroduced greenhouse gases into the atmosphere eventually warming the Earth and melting the snowball.

Now, if we look at the advent of photosynthesis that led to a Snowball Earth episode that wiped out almost all life, we can infer that there was certainly no biological foresight. But, more importantly there seems to be no evidence of a biological climate sensor. If there was a biological climate sensor, it was totally powerless to provide adequate feedback to prevent the cooling. From this we can also infer that there were not significant Gaian mechanisms at work at this point in evolution. Life was lucky that nonbiological forces happened to rescue the Earth from this deep freeze. There are two criticisms to anticipate. First, perhaps the biosphere had simply not yet evolved strong Gaian mechanisms. The problem with this idea is that the biosphere itself cannot be considered life because it does not self-replicate. This is not a matter of semantics, self-replication is required for evolution to occur through natural selection, therefore Gaia will not emerge from evolution. Second, perhaps Gaian mechanisms became stronger by chance after this Snowball Earth episode. The problem with this idea is that it does not help Gaia triumph over blind luck. Lucky-Gaia is just blind luck.

Conclusion: how this alters the likelihood of finding complex or intelligent life

To recap, the Earth has enjoyed billions of years of climate stability, of course with a few blips like the Snowball Earth episode. The sun’s initially lower but steadily increasing output was counterbalanced by a decreasing greenhouse effect, and this was not an inevitable consequence of the biosphere. It seems to be just blind luck. How does this alter the likelihood of finding complex or intelligent life? The probability of complex or intelligent extraterrestrial life is severely diminished in this way because it increases reliance on the universal lottery. Of course, that doesn’t mean it doesn’t exist or that we shouldn’t look for it.

The Hiddenness of Freedom

Suppose that you parachute from an airplane into a vast unoccupied desert. The lifeless sand is a warning. You have enough supplies in your pack to last a week. You look across the east horizon for any sign of hope. To your surprise there is something off in the distance, a vague object. To the north there is nothing as far as the eye can see. To the west there is, to your surprise, another vague object. To the south – nothing. Which object do you seek out, the east or west? The objects are as vague as to be indistinguishable. It seems that choosing one or the other is a matter of pure randomness, so without any more consideration you start heading east. After several days of trekking, the eastern object is beginning to take form. Finally, it appears to be a rock formation with some skeletons, an ominous sign! What do you do? You decide to retrace your journey and make for the other vague object. Several days later. . . it feels as if death is encroaching as your supplies dwindle. You are parched; the sun threatens to burn the flesh right off your bones. Thankfully, the other object begins to take form. It is just another rock formation, but is that some green? At closer inspection there is a small green plant. You climb the rocks and look upon the other side. . . Is this a mirage? A hallucination induced by dehydration? An oasis appears before you complete with water and palm trees!

Where is our freedom?

Some say there is no freedom. Human actions are entirely determined by circumstances and the brain, an immensely complex computer. As you traverse reality, you are not “deciding” anything at all; in fact, the brain already had an answer before the question was asked. The brain already had the output before the input was received because with any given input there was only one possible output. And, any feeling of freedom is simply an illusion. But, has science ruled out the possibility of freewill? Is science even capable of detecting systems with freedom? A system with freedom may be unpredictable enough as to be hidden from science.

My thinking is that, yes, a form of freewill does exist amidst the deterministic components of the brain. The freedom is found in the ability to seek, to inquire, and to ask. One might argue that these tendencies are innate, that we don’t actually have a choice to seek. This may be true in many or most instances, but it may be that there are instances in which a true expression of freedom, a decision to seek truth and morality, is undertaken. We don’t have to know when we express freedom to be expressing freedom. Indeed, an expression of freedom may be hidden from our own knowledge.

As we are surrounded by vague objects in the distant horizon, we have the ability to seek their true form, hoping to uncover just a tiny bit of the mystery we find ourselves surrounded by. Hopefully we can find an oasis.