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| Bangkok |
Here's the notes I'll give the students. Very few of them will have ever heard something like this, so I'll go slow and do my best to explain.
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The Fine-tuning argument for God’s existence reasons for God’s existence using “inference to the best explanation.” (IBE)
In IBE “we reason from premises about a state of affairs to an explanation for that state of affairs.” (Vaughn, The Power of Critical Thinking, 344)
The premises, in IBE, are statements about observations or evidence to be explained.
The explanation is a claim about why the state of affairs is the way it is.
So, given some state of affairs, what is the best explanation for the existence or nature of that state of affairs? “The best explanation is the one most likely to be true, even though there s no guarantee of its truth as there is in a deductive inference.” (Ib.)
IBE has this pattern:
1. Phenomenon Q.
2. E provides the best explanation for Q.
3. Therefore, it is probable that E is true.
THE FINE TUNING ARGUMENT FOR GOD’S EXISTENCE
Imagine we finally arrive on Mars, and find a clear domed structure containing plant and animal life. Suppose the environment inside this biosphere is perfect for life. The temperature is 80 degrees F; the relative humidity is 50%. The biosphere has an oxygen-recycling system and a system for the production of food and water.
Call this state of affairs Phenomenon Q. What is the best explanation of its existence? Consider these two alternative explanations:
a. The biosphere came about as a result of natural processes alone.
b. The biosphere was made by an intelligent designer.
Clearly, using IBE, a is so unlikely and improbable that we would not consider it. Alternative explanation b, if true, makes Phenomenon Q unsurprising.
This example forms an analogy to our universe. Our universe is “just right” for life to exist. “It is, in effect, a biosphere with an environment fine-tuned to render life possible.” (Stairs and Bernard, A Thinker’s Guide to the Philosophy of Religion, 40) Phenomenon Q is: Our universe is fine-tuned to render life possible. The fine-tuning argument, using IBE, then looks like this:
1. Our universe is fine-tuned to render life possible.
2. The two explanations for this fine-tuning are:
a. Atheism: The fine-tuning came about by natural processes alone (and therefore by chance or coincidence).
b. Theism: an intelligent designer fine-tuned our universe for life.
3. If explanation a is true then our fine-tuned universe seems wildly improbable.
4. If explanation b is true then our fine-tuned universe is not improbable.
5. Therefore theism is probably true.
Crucial to this argument is the truth of premise 1. (P1) P1 is affirmed by atheists and theists alike. For example, atheists Hawking and Mlodinow in their recent book The Grand Design say: “Our universe and its laws appear to have a design that is both tailor-made to support us and, if we are to exist, leaves little room for alteration. That is not easily explained, and raises the natural question of why it is that ay.” (Hawking and Mlodinow, The Grand Design, 162)
Princeton physicist Freeman Dyson has said: “There are many lucky accidents in physics. Without such accidents, water could not exist as liquid, chains of carbon atoms could not form complex organic molecules, and hydrogen atoms could not form breakable bridges between molecules.” In short, life as we know it would be impossible. (Quoted in Stairs and Bernard, 41)
Theoretical physicist Paul Davies claims that with regard to the structure of the universe, “the impression of design is overwhelming.” (In Ib.)
There are many physical examples of the fine-tuning, to include:
1. The strength, or value, of gravity must be just right. If the gravitational constant were a little weaker, all stars would have been blue giants, which burn too briefly for life to develop. If the gravitational constant were slightly stronger, land-based animals the size of humans would be crushed. If it were even greater, all stars would have been red dwarfs, which are too cold to support life-bearing planets.
2. The strong nuclear force must be just right. Just a 1% increase would result in almost all carbon being burned into oxygen. A 2% increase would preclude proton formation from quarks, preventing the existence of atoms.
3. By some counts there are over 100 physical, fine-tuned constants. (See Stanford Encyclopedia of Philosophy, “Teleological Arguments for God’s Existence,” 4.1 – “Cosmic Fine-tuning.”)
4. Hawking and Mlodinow write: “Most of the fundamental constants in our theories appear fine-tuned in the sense that of they were altered by only modest amounts, the universe would be qualitatively different, and in many cases unsuitable for the development of life.” (op. cit., 160)
5. Hawking and Mlodinow, once more: “Were it not for a series of startling coincidences, in the precise details of physical law, it seems, humans and similar life-forms would never have come into being. The most impressive fine-tuning coincidence involves the so-called cosmological constant in Einstein’s equations of general relativity.” (Ib., 161)
So, to repeat, Phenomenon Q is: our universe is exquisitely fine-tuned for the existence of life.
On atheism this state of affairs is wildly improbable, and would be like explaining our Martian biosphere as having naturally formed by chance.
On theism this state of affairs is very probable, and would be like explaining the Martian biosphere by postulating an intelligent designer.
Our existence is highly improbable on the atheistic hypothesis, but not improbable on theism.
Another way of putting this is:
1. The existence of the fine-tuning is a surprising state of affairs.
2. But if theism is true, the existence of this state of affairs is not surprising.
3. Therefore there is reason to suspect that theism is true. (See Stanford Encyclopedia of Philosophy, op. cit.)
For these reasons I find it rational to believe in God. The Stanford Encyclopedia of Philosophy says, in regard to this: “Barring any viable alternative, cosmic fine-tuning via deliberate agency seems to many to constitute a live candidate for a design argument.” (op. cit.)
(Note: for objections to the fine-tuning argument Stairs and Bernard [op. cit.] is very good.)
