"Dr.
Yardley, couldn't one argue," postulated Mr. Tappin, "that throughout history,
including the history of science, there have been a succession of aesthetic theories of
truth, if you will, which have been quite captivating and alluring during their time, but,
with the passage of time, the beauty of these theories has faded?"
"Yes,
this frequently has been the case," acknowledged the professor.
"Moreover,"
the defense counsel continued, "don't we all, whether or not we are scientists,
constantly have to grapple with the possibility that what we find beautiful may, in
reality, be a counterfeit, or an illusion, or purely a subjective projection being imposed
onto the character of experience or reality?"
"Yes,"
the professor said.
"Furthermore,
Dr. Yardley, would you agree," the lawyer asked, "that, perhaps, on occasion,
the reason why we find a theory beautiful is because it serves our personal interests,
needs and aspirations, rather than because the theory's beauty is an index for, or sign
of, the presence of truth."
"Again,
I would agree, in principle, with what you are saying," affirmed the professor.
"In
addition," Mr. Tappin pressed, "isn't it possible that what we take to be the
reflective beauty of truth and reality is but the reflection of a scientific, political,
religious, cultural and/or philosophical conception of beauty and truth into which we have
been initiated or indoctrinated by the formal and informal aspects of the educational
processes to which we have been exposed during our lives?"
"Of
course, this is a possibility," remarked the professor.
"Lastly,
Dr. Yardley, don't myths have many of the same kinds of properties which you have outlined
with respect to the idea of beauty? In other words, don't myths have the capacity to offer
organized systems of: directed meaning, simplicity, heuristic value, symmetry and a
certain kind of integrity and nobility of purpose?"
"Yes, I
suppose so," the professor responded, "but I believe the qualities of beauty in
science are a lot more sophisticated, methodologically sound, and analytically rigorous
than anything which might be generated through myths."
"Maybe
you feel this way, Dr. Yardley, because you are firmly caught up in the myths of science.
Isn't this possible?"
"Perhaps,"
stated the professor.
Glancing at
the material in his hands, Mr. Tappin asserted: "In earlier testimony, we have
established that, so far as is known, there is no ribozyme capable of unwinding double
helical structures which have assumed a stable state through Watson-Crick pairing. In
similar fashion, Professor, is there any naturally occurring ribozyme that has proven to
be capable of serving as the RNA-world's counterpart to the exonuclease proteins which are
able to eliminate errors during the replication of nucleic acid polymers?"
"Not so
far," Dr. Yardley indicated.
"What
happens if there is no means of maintaining replicational fidelity from one generation to
the next?" Mr. Tappin asked.
"Within
limits," Dr. Yardley pointed out, "a system can tolerate a certain amount of
replicational infidelity. A lot depends on where such errors occur since some pathways and
functions are a lot more crucial than are others.
"In
addition, under some circumstances, errors in replication actually serve a positive
function. Such errors become the mutations through which new evolutionary possibilities
may be introduced into the system.
"However,
when the replicational fidelity of a genetic system falls below a certain level, then
vital information is lost, not only with respect to the individual, but also in relation
to the species population as well. Generally speaking, any kind of replicational process
that falls much below, say, a 96-99 percent fidelity rate per nucleic acid residue is very
likely, sooner or later, to run into problems which will challenge the continued existence
of the kinds of pathways, reactions, structures, activities and functions that are being
underwritten by such a replicational process."
"If the
RNA-world hypothesis is to be taken seriously," postulated the defense counsel,
"wouldn't it have to be able to propose some plausible way to ensure that the
fidelity of replication from one RNA generation to the next could be maintained? In fact,
wouldn't such a capacity be of the utmost importance given the vast range of abnormal
nucleotides and nucleosides which are likely to be roaming about in an Archean era
environment?"
"Yes,"
agreed the professor, "an exonuclease-like capability would be very important to an
RNA-world, just as such a capacity is crucial to the DNA-world in which we live."
"I'm
sorry, Professor, could you briefly explain what an exonuclease is," Mr. Tappin
requested.
"Perhaps,
the easiest way to describe the function of this kind of molecule" responded the
professor, "is to say they are able to identify and eliminate the vast majority of
errors which may arise during, say, the process of replication."
"Thank
you," the lawyer acknowledged, and then he proceeded to ask: "Can one assume,
Dr. Yardley, that a plausible RNA-world hypothesis would require substantially fewer kinds
of functions- such as, but not limited to, the just mentioned exonuclease, than the
DNA-world requires in the way of structural and enzymatic proteins?"
"No, I
wouldn't think so," the professor replied.
"Yet,"
challenged the defense counsel, "only a very few, limited ribozymes have been
discovered so far. How do these few discoveries lend much plausibility to a RNA-world
hypothesis?"
"First
of all," Dr. Yardley responded, "these discoveries are important because of
their implications. The fact there may be few ribozymes in existence today does not
preclude these molecules from having been a dominant force at some early stage of
evolutionary history.
"Secondly,
and related to the first point, the ribozymes we have been finding may merely be the
left-over remnants of the order of things which once was, just as our appendix may be an
evolutionary remnant of an organ or process which once had a function at some point in our
evolutionary past. These sorts of evolutionary relic are found throughout the animal and
plant worlds.
"Thirdly,
the discovery of ribozymes opened up a lot of conceptual possibilities that helped set the
stage for a variety of exploratory probes, both experimental and theoretical in character.
A lot of important work has come out of the RNA-world hypothesis which has helped to
expand the horizons of the evolutionary model in a number of ways.
"Admittedly,
there are quite a few outstanding problems facing the RNA-world hypothesis. However, even
if this hypothesis is eventually rejected or abandoned, science and evolutionary theory
will have benefited by going through the rigorous processes of questioning, experimenting,
analyzing and reflecting which have been necessary in order to properly consider the
possible tenability or value of such a hypothesis."
"Gentlemen,"
interjected Judge Arnsberger, "I feel the time has come to put the discussion to bed
for the night. We'll pick things up again tomorrow morning at 10:00 a.m..
"I
trust the jurors will continue to behave themselves with respect to the restrictions which
have been placed on their discussing the case with anyone. Court is adjourned."
