Thursday, June 10, 2010

The Gaia Hypothesis - Three Levels of Interpretation

I posted my first Gaia Topic to this Blog back on Earth Day, April 2010.

This new Topic is based on a talk I gave to the Philosophy Club here in The Villages in Central Florida, 11 June 2010. You can download a PowerPointShow of the talk with animated slides and an audio narration Part 1 and Part 2. [Click hyperlink for the Part you want, then click on Open, wait for the file to download, then click on Allow, and crank up the volume for the audio as the slide show starts!]

In the 1960's, James Lovelock was tasked by NASA to help find signs of life on Mars. As a result of his work for NASA, he came up with what he called the Earth Feedback Hypothesis. This is the idea that the Biosphere, which is the sum of all biological life on Earth, has developed, following the accepted principles of Evolution and Natural Selection, in a way that controls the gasses in the atmosphere and moderates the temperature of Earth in a way that tends to promote life. He suggested that, if Mars or any other planet has or used to have life, it would have telltale signs in the form of certain gasses and other measureable and unique characteristics.

At the suggestion of a neighbor who happened to be a novelist, he changed the name of his theory from the Earth Feedback Hypothesis to the Gaia Hypothesis, after Gaia, the Greek Goddess of Earth.

The Gaia Hypothesis may be viewed at three different levels of interpretation, (1) Pure Science, (2) Purpose-Directed Organism, and (3) Grand Unification of Science and Religion.


Let us stick to the basics of the Earth Feedback Hypothesis and avoid any suggestion of goal-directed behavior by the Biosphere. Let us ignore any spiritual or religious meaning. At this level we have a straightforward scientific hypothesis. Namely, that standard concepts of the Origin of Life by random mixing of molecules and subsequent Evolution and Natural Selection will tend to generate feedbacks that modify the atmosphere and temperatures of the host planet in a direction that supports continuation of life on that planet.

In my talk, I discuss the well-known "Daisyworld" thought experiment where a planet is planted with light-colored daisies that grow best in warmer temperatures and dark-hued daisies that thrive in cooler temperatures. Daisyworld reacts to a warming Sun by growing more light-colored daisies that raise the albedo (reflectiveness) of the planet in a way that moderates the heating by reflecting excess Sunlight back into space. Conversely, if the Sun cools, dark daisies will become more abundant, reducing the albedo of the planet in a way that absorbs the limited heat of the Sun and thus moderates the cooling. Thus, Daisyworld acts as if it had as its purpose the preservation of life.

I make use of Douglas Hofstadter's idea (in his 1980 Pulitzer-winning book, Godel, Escher, Bach) to argue that an anthill is a complex system that may be considered an organism. Hofstadter calls it Aunt Hillary because the anthill behaves as if it had a purpose, namely the preservation of the anthill and the long-term welfare of the ants. Aunt Hillary is in a mutually beneficial and symbiotic relationship with anteaters. She calls one Dr. Anteater and welcomes his visits because he removes deadwood ants and generally improves the health of the anthill.

The ants are "farmers" who use cut leaves to grow the fungi they eat and "herders" of smaller insects called aphids that secrete a sweet liquid ants drink. Aunt Hillary's anthill is in competition and cooperative relationships with other anthills. They continually invade each other's territory, competing for resources. Should any anthill fail, that territory and resources would be invaded and settled by ants from other anthills.

Of course anthills and anteaters do not exist in a vacuum. They are part of the ecological system of a lake or river valley made up of a balanced set of bacteria, plants, insects, and animals that, over evolutionary time, have settled into a web-of-life and food-chain. I call this ecology Valerie. The valley ecology is complex enough to be considered an organism made up of thousands of species that are in competitive and cooperative relationships with each other and with neighboring valleys. Ecologies are continually invading each other's territory, competing for resources. Should any valley ecology fail, that territory and resources would be invaded by bacteria, insects, plants and animals from other valleys.


Once we agree that an anthill (Aunt Hillary) and a balanced ecology (Valerie) behave as if they are purpose-driven and goal-directed, we are tempted to ask if they are or may become sentient. Is Aunt Hillary the sentient Gaia of the anthill? Is Valerie the sentient Gaia of the lake valley?

The talk examines what we really mean by sentience, and what is required for a complex system to become sentient.

The only certain example of a sentient organism we can all agree on is you (and me and all the other human readers of this Blog). What makes us sentient? Well, it is the complex system of billions of neurons, biological cells that make up our brains and central nervous systems. If billions of cells, each of which is descended from single-cell bacterial life that lived independently eons ago, can be sentient by exchanging chemicals (neuro-transmitters and neuro-inhibitors to and from nearby cells) and electrical signals (pulses transmitted to and received from thousands of other cells near and far), what other complex system could be sentient?

How about billions of humans and other animals in the web-of-life? Humans have been trading ideas, food and other useful items with each other since tribal times. Thousands of years ago trade caravans transported ideas and products far and wide. We now have telephone and computer networks that interconnect nearly all humans on Earth. Could that complex system be sentient? Have we created a Gaia that is a sentient organism?


The figure below traces the development of religion and science and indicates how the Gaia Hypothesis may unite them.

What we call primitive religion begins with the idea that every tree and river and tribe has a god within it. We must supplicate ourselves before the god of the tree and thank it for granting us its fruits, and the god of the river for its water, and so on. If our tribe battles yours, and we win, it is because our tribal god is stronger than yours! This evolves into the Egyptian or Greek or Roman pantheon of gods. In the Greek system, the chief god Zeus, and the various gods of the seas, the wind, war, and so on live on Mt. Olympus and cooperate and compete as they rule over us. This evolves into the great Monotheistic religions, Judaism, Christianity, and Islam, where a Universal God in Heaven is separate from His creation.

Science develops as we study the natural world. First with telescopes to bring far planets and stars closer and with microscopes to peer into the smallest corners of things. This develops into Physics, Chemistry, Biology, and the theories of Evolution, Atoms, Quantum Mechanics, and so on.

It would seem that Religion and Science are incompatible - but, there is hope!

On the RELIGION side, several hundred years ago we see the development of Unitarianism - the belief in one God AT MOST. Some of the founders of the American experiment were "Nature's God" Deists who believed that God Created the Universe and the Laws of Nature and then let it all play out on its own, with no miracles beyond that Original Creation. We also have Pantheists, such as Spinoza and Einstein (and me, your humble Blog administrator) who believe the Universe is God.

On the SCIENCE side we have James Lovelock and his Earth Feedback Hypothesis.

Put them all together and put them into a neat box and they point to the Gaia, the Goddess of the Earth!

Scientists can think of Gaia as a complex interactive system that may or may not be sentient, but who, at least, behaves as if She is sentient. Folks who are seeking a more spiritual solution can think of Gaia as a sentient, purpose-driven organism who came into being through the totally natural processes of Evolution and Natural Selection. Literal believers in Judaism, Christianity, Islam or any other established religion can snicker a bit and thank their God for gifting at least a small bit of Faith to their benighted brothers.

Ira Glickstein


Howard Pattee said...

Ira, that is certainly the most rational religion I have heard, and I think it is very stimulating and spiritually satisfying (or provocative and irritating if you are traditionally religious).

I'm not sure it should be called a science because I can't think of how it could be falsified. I would call it a scientific myth. That is, it is consistent with science, but goes beyond what science can empirically test.

Ira Glickstein said...

Thanks Howard - I appreciate your favorable reaction.

I guess the Earth Feedback Hypothesis could be falsified by empirical test if we discover some other planet with biological life that has not evolved a similar feedback mechanism that tends to stabilize gasses and temperatures on that planet in a way favorable to continuation of life.

I agree that the extension of the Gaia theory to a claim of sentience for a well-functioning anthill or a balanced valley ecology or the whole Biosphere cannot be falsified. But note that the theory that YOU are sentient cannot be falsified either. It could be that you are a zombie or a computer bot that only acts as if you are sentient. I believe you are sentient because I am sentient and you seem to be made of the same materials and basic design. But, how do I know I am really sentient? I could be a brain in a vat with stimulation provided by some mad scientist, or a software process in a giant computer matix.

I think we agree that humans -or at least most of us- are wired to want to believe in something or some power greater than ourselves. Traditional religions have satisfied that need. I believe a case can be made that religious myths are -on net- a positive lubricant (or "opium" as Lenin claimed) for societies. Some have suggested that extreme ecologist scientists are filling their religioso need with reverence for Nature and that greenhouse gasses and global warming fulfills their need for a Devil to balance their Natural God.

Ira Glickstein

joel said...

Frankly I don't get the Gaia Hypothesis. We also have the Medea Hypothesis. Long before all this started we knew a lot about complex feedback systems. Going under the title of system science or feedback theory or control theory, the mathematics of such situations has been well worked out. No one ever felt the need to superimpose a mystical framework on top of this.

We know that for a complex system to continue to exist in an environment of small perturbations it must have a sufficient amount of negative feedback. It can either react to changes in stimulus with a damped response, an overshoot or a continuous oscillation without the help of anything religious or mystical. If there's insufficient negative feedback or there is positive feedback then the system will overload or explode. (This is the case with stars.) We have many important cycles on Earth, for example, the water cycle. Water oscillates from liquid to gas to solid and back to liquid again in a stable oscillation as it passes from ocean to mountain to river to ocean again. Without drivers like the sun and Earth's strong gravity, our planet would be like our moon. It seems to me that the preponderance of dead celestial bodies in our solar system is evidence that too much negative feedback or too much positive feedback is possible and even likely. Phoebe, Mars, Venus, Jupiter, etc. don't seem to have done as good a job as Gaia in stabilizing their environments...or could it be that the causality really works?

Howard Pattee said...

The problem here is what we mean by “sentient.” Joel says the concept of feedback is enough. He says no one felt the need for a “mystical framework.” I would say no reductionist felt the need for a higher level framework. But it seems to me the same reductionist argument would hold for "sentience" and even "consciousness."

A reductionist would say that sentience is just a mystical framework for a complicated feedback system. Consciousness is even more mystical, but for a reductionist it is just one of the brain’s more complicated feedback systems.

This argument between reductionism and emergence is going on now even at the genetic level. Reductionists say the gene is really just a molecule obeying laws. There is no need for calling the genetic system a “symbolic language.” To the reductionist that is only a metaphor. I think Gaia is also a metaphor.

Most physicists have come to think of all scientific models as metaphors. Particles, waves, electron spin, matter, and energy are only models that in specific situations fit our observations. What the reality is behind these models is ineffable. The only issue is whether they are useful metaphors, and “useful” is a very subjective concept. It includes the feeling that you have explained something.

joel said...

Howard, I agree completely.

Howard Pattee said...

Ira says, “But note that the theory that YOU are sentient cannot be falsified either. . . I believe you are sentient because I am sentient and you seem to be made of the same materials and basic design. But, how do I know I am really sentient? I could be a brain in a vat . . . “

With modern imaging, like functional MRI, an observer can not only tell whether you are thinking, but can tell to some extent what you are thinking about. But I want to add that
Popper’s criterion of falsifiability is of limited value, and I should not have used it in the first place.

It is sometimes the case that a single measurement may falsify a theory, but physical theories are based on foundational epistemological principles, like symmetry and invariance, that are not falsifiable in the same sense. The only way to change such basic principles on which all current physical models depend would be to find new principles that lead to better models in all cases, and that is unlikely. A “better” model is too complex and subjective to be precisely defined. Ultimately it depends on the consensus of experts in the domain of the model.

Ira Glickstein said...

Joel said "Howard, I agree completely." OOPS - if we agree too much what will we talk about?

Joel said "Frankly I don't get the Gaia Hypothesis. We also have the Medea Hypothesis."

OK, you made me look up the Medea Hypothesis that life is, ultimately, suicidal. That reminds me of Edna St. Vincent Millay: "I burn my candle at both ends / It will not last the night; / But ah, my foes, and oh, my friends -/ It gives a lovely light." or the Epicurian motto: "Eat, live, and be merry - for tomorrow we die!" But I follow Epictetus and prefer to be optimistic about the continuation of life.

What part of the Gaia hypothesis that I outlined at three levels don't you get?

Surely the first, non-mystical level as I have described it is a valid scientific theory. Yes, it all has to do with complex feedback mechanisms which is why Lovelock first called it the "Earth Feedback Hypothesis". But, the mathematics of feedback and of over-, under-, and critically-damped systems does not seem adequate to model a living ecology that seems to have evolved the ability to control the atmosphere and temperatures in a way that promotes continuation of life.

All other feedback mechanisms I am aware of were designed by someone outside the system. If Lovelock is correct at the first level, the Biosphere has self-designed itself as if it had a purpose!

Your skepticism is certainly justified at the second level - the idea that the Biosphere, personalized as Gaia, is (or may become) sentient and conscious and actually goal-directed.

But you and I are sentient and conscious and goal-directed. You (and I) do not believe we were created by a Supernatural God, so we must accept that Natural processes (origin of life, evolution, natural selection) can shape ordinary matter into an electro-chemical machine that is conscious. Why should that process apply only to machines made of billions of biological cells and limited to a few hundred pounds? Why couldn't an organism be made of hundreds of thousands of ants who work together for the survival and reproduction of their anthill? Why couldn't billions of people connected by telephone and computer systems consititute a conscious organism?

I'm not saying I could prove that they do, but how can you be so sure they do not?

The third level of my description would appeal to a scientist who feels a need to believe in something greater than himself. Something that may prevent that suicide of the Media Hypothesis. You do not seem to have that need or, if you have it, you cannot get yourself to believe the Gaia may be the solution. I wish I could muster the literal belief some of my friends have in an external Creator God, but I cannot. The Gaia is the most I can make myself (kind-of) believe in.

Ira Glickstein

Anonymous said...

You speak of "primitive religion." Is but religion anything else than primitive?

Ira Glickstein said...

Thanks, "Anonymous", for your posting. You claim that all religion is primitive, writing: "You speak of 'primitive religion.' Is but religion anything else than primitive?"

Well, yes and no. Even if you are a non-believer in any current or past religion, I think you have to admit that religion, like most aspects of human civilization, has an historical arc of development.

In my posting, I claim that religion, as a belief in supernatural powers, begins with multiple gods, often spirits thought to inhabit certain plants and animals as well as elements and forces of Nature (wind, water, ...). It progresses towards a God that is local to our tribe or nation (in opposition to the God of an opposition tribe or nation). The next step is to a Universal God. Whether any of these beliefs is true or has any basis in science is immaterial to the historical fact of the general progression.

It is also true that all successful civilizations (defined as those that have lasted a century or more) have been based upon what you and I might call "myths" - a belief in some power superior to humans. It appears that evolution and natural selection has "wired" humans in that direction. That, of course, does not make any of these myths true, but it is evidence that they are at least useful, having stood the test of time.

My further point is that, IMHO, the next step in the progression of religious belief is from an external Universal God to what I consider to be the more rational belief that what believers call "God" (conceiving of God as a super-natural force above and separate from the Universe, who, they believe, actually created the Universe) is more rationally understood as the Universe, and all the Natural things and processes governed by what scientists call the Laws of Nature.

In a grand unification of science and religion (with an emphasis on the former) we may choose to believe that the Universe (or at least the Biosphere of the Earth) has evolved some sort of consciousness, above and beyond the level you and I have. If the billions of neurons in your brain, which are each no more than electro-chemical machines, have evolved to create what we experience as self and consciousness, why couldn't an anthill, or a pond ecology, or the entire Earth Biosphere, consisting of Billions of living things, have evolved into a similar consciousness?

An individual neuron in your brain has no idea it is a critical link in your understanding of language, or vision or anything else. Indeed, it has no idea it is part of You. All it experiences is a bunch of electrical pulses and neuro-chemicals coming in, and it mechanically outputs electrical pulses and chemicals, according to its genetically-determined structure. How different is that from a plant or animal or human, that also has a genetically-determined structure and experiences a multitude of inputs and reacts to them in a multitude of ways?

Ira Glickstein