Wednesday, August 09, 2023

The Fine-Tuning Argument for God's Existence

Fountain, at
Monroe County Community College

(I am re-posting this for a friend.)


The argument can be stated this way.

  1. The fine-tuning of the universe is due to either physical necessity, chance, or design.
  2. It is not due to physical necessity or chance.
  3. Therefore, it is due to design.
Define “fine-tuning”

Almost everything about the basic structure of the universe – for example, the fundamental laws and parameters of physics and the initial distribution of matter and energy – is balanced on a razor’s edge for life to occur.

Our fine-tuned universe is an event that demands to be explained.

Examples of fine-tuning

  1. If the initial explosion of the big bang had differed in strength by as little as one part in 10\60, the universe would have either quickly collapsed back on itself, or expanded rapidly for stars to form. In either case, life would be impossible. (An accuracy of one part in 10 to the 60th power can be compared to firing a bullet at a one-inch target on the other side of the observable universe, twenty billion light years away, and hitting the target.)
  2. Calculations indicate that if the strong nuclear force, the force that binds protons and neutrons together in an atom, had been stronger or weaker by as little as five percent, life would be impossible.
  3. If gravity had been stronger or weaker by one part in 10\40, then life-sustaining stars like the sun could not exist. This would most likely make life impossible.
  4. If the neutron were not about 1.001 times the mass of the proton, all protons would have decayed into neutrons or all neutrons would have decayed into protons, and thus life would not be possible.
  5. If the electromagnetic force were slightly stronger or weaker, life would be impossible, for a variety of different reasons.
And so on…

Premise 1 seems to exhaust the alternatives. The soundness of the argument depends on the plausibility of premise 2.

Premise 1

Can cosmic fine-tuning be plausibly attributed to physical necessity?

By “physical necessity” we mean: the constants and quantities must have the values they do. If this is true, there was really no chance of the universe’s not being life-permitting.

But this alternative seems extraordinarily implausible. Because it requires us to believe that a life-prohibiting universe is physically impossible. But surely a life-prohibiting universe seems possible. That, e.g., the universe might have expanded just a bit more slowly does not seem physically impossible.

A person who claims that the universe must be life-permitting is taking a radically position that requires strong proof. But as of now there is no such proof.

NOTE: support for the idea of “physical necessity” being false is given, inadvertently, by multiverse theorists. Such theorists use multiverse thinking to show that, while nearly all possible universes are life-prohibiting, it’s possible that one or more could be life-permitting.

Can cosmic fine-tuning be plausibly attributed to chance?
Philosopher John Leslie gives an example, as an analogy, to show the implausibility of the universe coming into existence by chance.

Suppose you line up against a wall and 50 sharpshooters take aim at you and fire. All of them miss. This event demands an explanation, for their missing me is needed for my survival.

I shouldn’t at all be surprised that I observe that all the bullets missed me, since I am alive to observe that they did all miss me. There is nothing improbable about that at all.

But I should be very, very surprised that in fact all the bullets missed me. That seems very, very improbable.

It seems reasonable to infer: design. That is: the sharpshooters missing me was planned for my continued existence.

This is a case of “inference to the best explanation.”

Analogically, the fact of the fine-tuned universe means the universe is life-allowing rather than life-prohibiting. This is very imporbable on atheism. This is not improbable on theism.

 The main atheist objection to this is multiverse theory. “If there is only one universe,” British cosmologist Bernard Carr says, “you might have to have a fine-tuner. If you don’t want God, you’d better have a multiverse.” (Discover, December 2008)