[ Extended version of my previous critique ]
Extracts from http://www.talkorigins.org/faqs/abioprob.html :
| Problems with the creationist "it's so improbable" calculations:
The genuine problems are rather on the neo-Darwinian side. BTW,
I'm an uncompromising evolutionist (i.e. I'm convinced of a
continuous emergence of the world and of life).
| 1) They calculate the probability of the formation of a "modern"
| protein, or even a complete bacterium with all "modern" proteins,
| by random events. This is not the abiogenesis theory at all.
A probability of 10^-100 is enough to refute abiogensis, so
it doesn't help to criticize calculations resulting in e.g.
10^-1000000.
For comparison: in the order of 10^20 milliseconds have passed
since the birth of the earth, a planet consisting of in the
order of 10^50 atoms. This results in 10^70 "atom-milliseconds".
It is obvious that the number of any reasonably defined
"abiogenesis events" is by many orders of magnitude lower than
the number of "atom-milliseconds".
Even if we assume that 1) around 10^20 planets could have given
rise to us, and that 2) one single successful abiogenesis event
leads inevitably to higher forms of life, a probability of
10^-100 would still make our existence very improbable.
Because neo-Darwinism is not even consistent with the evolution
of the upright gait in humans, assumption 2) is obviously
untenable. See http://www.deja.com/=dnc/getdoc.xp?AN=698302471
| 2) They assume that there is a fixed number of proteins, with
| fixed sequences for each protein, that are required for life.
This assumption is not necessary in order to refute (purely
materialistic) abiogenesis, because the improbabilty lies
already in functional constraints which are a prerequisite
for any form of self-replication.
If six protoenzymes with each a probability of at most 10^-10
are necessary for self-replication to start, we get already a
probability lower than 10^-60.
The probability of random emergence of a proto-enzyme cannot
be higher than 10^-10 even if it consists of only 10 rather
widespread building blocks.
Such a value must include both the probability that a
correctly bonded system of 10 building blocks arises and the
"combinatorial probability". (0.5 * 0.2)^10 results in 10^-10,
where 0.5 is the probability of correct bonds per building
block and 0.2 the combinatorial probability per building block.
The FAQ ("Coin tossing for beginners and macromolecular
assembly") completely ignores the question of the "bonding
probability". Only the combinatorial probability of a
(32 amino acid long) sequence is taken into account and the
experimental fact that correctly chained 32 aa-long sequences
do not arise abiotically is discarded.
And we must keep in mind that the final product of abiogenesis
must be able to undergo neo-Darwinian evolution and to survive
a change in its environment (e.g. drying up of the primordial
pond).
Also if "not even a protobacteria, or a preprobacteria" is
necessary for further evolution by replication with mutation
and selection to start, "but one or more simple molecules
probably not more than 30-40 subunits long", then we still
remain with the fact that the average probability of correct
bonds with viable neighbours is certainly lower than 0.1 per
subunit. So the probability of the emergence of one "simple
molecule" of this kind is still lower than 10^-30.
On abiotic formation of peptide chains:
http://www.deja.com/=dnc/getdoc.xp?AN=507707704
The abiotic emergence of RNA enzymes is even more questionable
because it contains ribose. Ribose is not even resistent to
water of normal temperature.
http://members.lol.li/twostone/E/deja3.html --> ribose
| 3) They calculate the probability of sequential trials, rather
| than simultaneous trials.
This statement can be interpreted either as a strawman
or as a summary of a central error of the FAQ, namely the
assumption that whole protoenzymes emerge by simultaneous
trials, and not by sequential steps (i.e. addition and
breaking off of building blocks).
http://members.lol.li/twostone/E/deja6.html --> 21-Mar-1999
| 4) They misunderstand what is meant by a probability calculation.
Those who declare simple and logically correct common-sense
reasonings wrong in order to save the currently prevailing
"scientific" dogmas are the ones who "misunderstand what is
meant by a probability calculation".
| 5) They seriously underestimate the number of functional
| enzymes/ribozymes present in a group of random sequences.
The low actual number of functionally equivalent proteins and
even DNA-coding sequences is rather evidence against the
relevance of this argument.
See: "The Death of Neo-Darwinism (was: Molecular Sequence Proof of
Common Descent)" in http://members.lol.li/twostone/E/deja4.html
The fact that each of e.g. 90% of the amino acids of a protein
can be replaced by others without loss of function does not
entail that the protein would still work if most of these
replaceable amino acids were replaced at the same time.
But even if we accept the argument, in this context it does not
change a lot whether the combinatorial probability of a 100 amino-
acid long enzyme is 20^-100 or 4^-100 (leading to 5^100 viable
variants).
| [T]he formation of biological polymers from monomers is a
| function of the laws of chemistry and biochemistry, and these
| are decidedly not random.
The laws of chemistry and biochemistry do indeed lead to the
needed chemical bonds. (They also lead to undesired bonds and
to the decay of desired bonds. If peptids are synthesized in
vitro, special methods are needed in order to prevent undesired
chemical bonds.)
However these laws do not concern the question whether a final
sequence is able to fold into an enzyme and to carry out complex
tasks. So these laws have rather to do with the probability
of correctly chained sequences long enough to arise at all
than with the combinatorial probability of such sequences.
Wolfgang Gottfried G.
The mystery of evolution explained in a logically consistent way:
http://members.lol.li/twostone/E/psychon.html
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