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.
1 - PURE SCIENCE - EARTH FEEDBACK HYPOTHESIS
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.
2 - PURPOSE-DIRECTED ORGANISM - THE GAIA (AS A GODDESS) HYPOTHESS
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?
3 - GRAND UNIFICATION OF SCIENCE AND RELIGION
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.