Arguments Against Darwin
It’s only a theory
What are the chances…
Irreducible Complexity (ID)
Second Law of Thermodynamics
Microevolution vs Macroevolution
Transitional Forms and Missing Links
It’s only a theory
Science is an attempt to understand the universe based
o n the assu mptio n of unifor mity of law. This
understanding is expressed in laws and theories. Law and
theory are words with many meanings. For our purposes,
scientific laws are simply descriptive statements. Laws
describe regularities discovered in natural phenomena by
scientists. The validity of scientific laws is tested by
their ability to predict the future and explain the past.
Laws are either accurate or inaccurate descriptions of
how nature behaves. Let’s think of theories as more
general than laws and as having a different function.
Theories are currently accepted understandings of how
nature works.
For scientists, theories are not
theoretical in the sense that term is used by most
nonscientists.
Law of Gravitational Attraction
versus Theory of Gravity
Law of Faunal Succession
is explained by the
Theory of Evolution
It’s only a theory
Uniformity of law is the assumption that natural laws are
constant in time and space. Such an assumption can
never be proven true beyond all shadow of doubt.
However, it does accord with experience and is thus
justified. By assuming uniformity of law, scientists have
induction available to them as a tool in reasoning about
any past, present or future state of the universe. Most
scientific claims are either inductive generalizations or
inductive analogies.
Arguments by analogy are often
persuasive but never logically compelling.
Role of belief (assumption) in science and religion?
It’s only a theory
Scientists prefer elegant theories. Elegant theories
are simple and powerful. Simplicity is an aesthetic
criterion. Power is a utilitarian one. Powerful theories
explain lots of phenomena. No theory explains
everything. Don’t think of theories as “true or false”,
“right or wrong”, “proven or unproven” sorts of things.
Theories are either accepted or unaccepted. Theories
are widely accepted if they explain lots of things.
Scientists are especially impressed by theories that
explain seemingly unrelated phenomena. This is known
as consilience.
What are the chances…
one million mutations each with 50% chance
amoeba
2
1,000,000
man (?)
The Bridge Hand
• Distribute 13 cards to each of four players.
• Chances of dealing ‘perfect’ hand?
1 in 2,235,197,406,895,366,368,301,559,999
• Chances of dealing any hand?
Irreducible Complexity
If it could be demonstrated that any complex organ existed,
which could not possibly have been formed by numerous,
successive, slight modifications, my theory would absolutely break
down. (CRD 1859)
Intelligent Design
Human Ignorance
Second Law of Thermodynamics
Kelvin Statement of the Second Law: No process is possible in which the sole result
is the absorption of heat from a reservoir and its complete conversion into work.
Clausius statement of the Second Law: No process is possible in which the sole
result is the transfer of energy from a cooler body
Natural processes are accompanied by an increase in the entropy of the system.
Cosmos to Chaos
Order to Disorder
diagram from Atkins (1984)
Second Law of Thermodynamics
Entropy is energy (heat) unavailable to do work.
…entropy, symbolized by S, is a measure of the unavailability of a system’s energy to do work.
It is a measure of the randomness of molecules in a system and is central to the second law
of thermodynamics and the fundamental thermodynamic relation, which deal with physical
processes and whether they occur spontaneously. Spontaneous changes, in isolated systems,
occur with an increase in entropy. Spontaneous changes tend to smooth out differences in
temperature, pressure, density, and chemical potential that may exist in a system, and entropy
is thus a measure of how far this smoothing-out process has progressed.
Wikipedia [accessed 8-22-08]
increase in entropy
smoothing out = ‘chaotic’
isolated systems!
diagrams from Atkins (1984)
Water on a freezing sidewalk?
Microevolution vs Macroevolution
Fleeming Jenkin (1833-85)
North British Review 1867
limits of variability
Change
Peppered moths
Time
pictures from Wikipedia
accessed 8-26-08
But the chief cause of our natural unwillingness to admit that
one species has given birth to other and distinct species, is that
we are always slow in admitting any great change of which we
do not see the intermediate steps. The difficulty is the same as
that felt by many geologists, when Lyell first insisted that long
lines of inland cliffs had been formed, and great valleys
excavated, by the slow action of coast-waves. The mind cannot
possibly grasp the full meaning of the term of a hundred million
years; it cannot add up and perceive the full effects of many
slight variations, accumulated during an almost infinite number of
generations. (452-453)
Transitional Forms (?) and Missing Links (!)
The Fossil Record
Why then is not every geological formation and every
stratum full of such intermediate links? Geology assuredly
does not reveal any such finely graduated organic chain; and
this, perhaps, is the most obvious and gravest objection
which can be urged against my theory. The explanation lies,
as I believe, in the extreme imperfection of the geological
record. (CRD 292)
Tiktaalik 2006