LECTURE 22

THE FINE-TUNING ARGUMENTFOR DESIGN

THE INITIAL COMPETITORS

• NATURALISTIC (SINGLE WORLD) HYPOTHESIS (NH1): Reality consists of a single material, spatiotemporal universe. Its existence and laws are just “brute facts.”

• THEISTIC HYPOTHESIS (TH): There is an omnipotent, omniscient, eternal being who created the universe.

THE DATA: D

• Fine-tuning of the laws of nature• Fine-tuning of the constants of the laws of

nature• Fine-tuning of the initial conditions of the

universe• Beauty and intelligibility of the laws of nature (Also: Beauty of mathematics itself)

THE TWO ARGUMENTS

D ___________ (Probably) The Naturalistic Hypothesis is true (NH1)

---------------------------------------------------------------- D___________ (Probably) The Theistic Hypothesis is true (TH)

COMPARING ARGUMENTS FOR INDUCTIVE STRENGTH

• We will compare these two arguments and decide which one has the greatest inductive strength.

• The basis for the comparison is a principle of inductive logic: The Likelihood Principle (a.k.a. Prime Principle of Confirmation).

• The outcome of the evaluation will be that one argument supports (inductively) its conclusion to a greater degree than the other.

PRIME PRINCIPLE OF CONFIRMATION(“THE LIKELIHOOD PRINCIPLE”)

• When comparing two hypothesis (e.g. NH1 and TH) with respect to certain observed evidence (e.g. D), the hypothesis that would make it more likely to observe that evidence is more highly confirmed by the observation (i.e., is made more probable).

FINE-TUNING OF LAWS

• If any of the following did not exist, then self-reproducing , complex life forms could not exist:

• 1. A universal attractive force like gravity.• 2. A force like the strong nuclear force which

binds together particles into the nuclei of atoms.• 3. A force similar to the electro-magnetic force.• 4. Bohr’s Quantization Rule• 5. The Pauli Exclusion Principle

FINE-TUNING OF THE CONSTANTS OF NATURE

• If the constants in the laws of nature had values outside of an extremely small range, then complex life forms would be impossible:

1. The Gravitational Constant (which determines the strength of the force of gravity)

2. The Cosmological Constant (which determines, among other things, the rate of expansion of the universe).

3. Mass of the neutron.4. Strength of the weak force. (and many others)

FINE-TUNING OF THE INITIAL CONDITIONS AFTER THE BIG BANG

• If conditions immediately after the Big Bang has been very slightly different, complex life forms would have been impossible:

• 1. The mass-density of the early universe.• 2. The strength of the Big Bang explosion.• 3. The strength of the energy perturbation that

led to star formation.• 4. The ratio of radiation density to the density of

ordinary matter.And many others…

EVALUATION ARGUMENT

1. The existence of fine-tuning (and beauty) is not improbable under Theism (TH)

2. The existence of fine-tuning (and beauty) is very improbable under Naturalism (NH1 – Naturalistic Single Universe Hypothesis)

3. The fine-tuning (and beauty) data D provides strong evidence to favor the design hypothesis over the atheistic single-universe hypothesis.

THIS DOES NOT SETTLE WHICH HYPOTHESIS IS MOST REASONABLEARGUMENTS THAT ARE ONLY

INDUCTIVELY STRONG (AND HENCE NOT DEDUCTIVELY VALID) ARE SUBJECT TO A VERY IMPORTANT CONDITION:

THE REQUIREMENT OF TOTAL EVIDENCE

A PECULIARITY OF INDUCTIVELY STRONG ARGUMENTS

AN ARGUMENT MAY BE INDUCTIVELY STRONG, BUT WHEN NEW PREMISES ARE ADDED TO THE GIVEN PREMISES, THE RESULTING ARGUMENT MAY BE INDUCTIVELY WEAK(!)

WHAT PREMISES SHOULD ONE USE?

• THIS MEANS THAT AN INDUCTIVELY STRONG ARGUMENT NEED NOT PRESERVE REASONABLE BELIEF: IT MAY BE REASONABLE TO BELIEVE THE PREMISES OF SUCH AN ARGUMENT (ITS PREMISES MAY EVEN BE KNOWN TO BE TRUE) AND IT MAY HAVE A VERY HIGH DEGREE OF INDUCTIVE STRENGTH, AND YET IT MAY BE REASONABLE TO BELIEVE ITS CONCLUSION.

THE REQUIREMENT OF TOTAL EVIDENCE

(RTE) IT IS NOT REASONABLE TO BELIEVE THE CONCLUSION OF AN INDUCTIVELY STRONG ARGUMENT ON THE BASIS OF ITS PREMISES UNLESS THE PREMISES CONTAIN ALL THE KNOWN RELEVANT EVIDENCE.

(BERNOULLI, J.M. KEYNES, CARNAP)

WHILE FINE-TUNING SUPPORTS TH OVER NH1, OTHER EVIDENCE

COUNTS THE OTHER WAYWE WILL NOT HERE DISCUSS THE PROBLEM OF

EVIL – AN ARGUMENT (OR ARGUMENTS) WHICH SEEMS TO COUNT AGAINST TH. IT WOULD BE INTELLECTUALLY IRRESPONSIBLE AND, WELL, IRRATIONAL TO IGNORE SUCH EVIDENCE IN DECIDING WHETHER (TH) IS MORE REASONABLE THAN (NH1)

ANOTHER IMPORTANT CONSIDERATION

IN DECIDING THAT ONE HYPOTHESIS IS MORE REASONABLE THAN ANOTHER, EVEN ON ALL AVAILABLE EVIDENCE, ONE MUST NOT OVERLOOK THE POSSIBILITY THAT THERE MAY BE A HYPOTHESIS THAT IS MORE REASONABLE STILL.

ONE MUST CONSIDER THE NATURALISTIC MANY UNIVERSES HYPOTHESIS NH2.

VAN INWAGEN’S EVOLUTIONARY MANY UNIVERSES HYPOTHESIS

VAN INWAGEN SUGGESTS A NATURALISTIC HYPOTHESIS WHICH HE CLAIMS MAKES THE OBSERVED EVIDENCE JUST AS LIKELY AS THE THEISTIC HYPOTHESIS. THEREFORE, HE CONCLUDES, THE EVIDENCE DOES NOT SUPPORT DESIGN OVER NATURAL MECHANISMS.

CHANCE AND AN OBSERVATIONAL SELECTION EFFECT

NH VI: THE OBSERVED COSMOS IS ONLY ONE AMONG A VAST NUMBER OF COSMOI. SUPPOSE ALSO THAT THE OTHER COSMOI ARE “SCREENED OFF” FROM US.

THIS HYPOTHESIS MAKES IT PROBABLE THAT SOME COSMOI WILL BE FINE-TUNED. NO DESIGN IS REQUIRED. MAYBE IT EVEN MAKES THE DATA MORE PROBABLE THAN THEISM DOES.

OF COURSE, WE MUST COMPARE THESE HYPOTHESIS ON ALL THE

EVIDENCE (RTE)

BUT THE FINE-TUNING OF OUR COSMOS DOES NOT BY ITSELF RENDER THEISM MORE REASONABLE THAN NATURALISM (ACCORDING TO VAN INWAGEN).