LECTURE 22
THE FINE-TUNING
ARGUMENT
FOR 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 selfreproducing , 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 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 NH1, 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 (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).