LECTURE 22 THE FINE-TUNING ARGUMENT FOR DESIGN

THE INITIAL COMPETITORS NATURALISTIC (SINGLE WORLD) HYPOTHESIS (NH 1 ): 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 (NH 1 ) 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. NH 1 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 (NH 1 – 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 REASONABLE ARGUMENTS 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 NH 1, OTHER EVIDENCE COUNTS THE OTHER WAY WE 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 (NH 1 )

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 NH 2.

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).