Mr. Tappin
briefly left the area of the witness stand and returned to the defense table. He whispered
something to his colleague who rifled through some material on the table and pulled out a
sheet of paper which he handed to the defense lawyer.
As the
lawyer came back toward the witness, he started to speak. "Professor Yardley,"
he inquired, "are you familiar with a 1993 report by a NASA experimental team
concerning the composition of interstellar dust?"
"In
general, yes, I am familiar with that report," answered the professor, "but some
of its details are rather fuzzy in my mind."
"Let me
refresh your memory," offered Mr. Tappin. "The NASA scientists examined a number
of star-forming clouds in the Milky Way galaxy."
"In
every star-forming cloud, without exception, examined by the NASA team, they discovered
that carbon in the form of microscopic diamonds dominated these clouds. In fact, these
microscopic diamonds were found in huge numbers, and at planetary masses.
"The
findings of the research team have been described as a challenge to existing theories of
both galactic and star formation. These prevailing theories assumed that interstellar
clouds were composed of softer hydrocarbons, somewhat similar to gasoline or candle wax.
"Dr.
Yardley, in the light of your previous answer about the availability of different
exogenous sources for entering into solution should the opportunity arise, what are the
implications of the largely hard-carbon, or microscopic diamond, composition of
interstellar clouds?"
"Probably,"
surmised the professor, "one would have to revise downward one's estimates of the
quantities, and the kinds, of soft hydrocarbons which might have come to Earth by means of
its passage through such interstellar clouds. How much these estimates would have to be
revised in a downward direction would depend on the extent to which the hard-carbons
dominated these interstellar clouds."
Once again,
Mr. Tappin returned to his table. On this occasion, his colleague was waiting for him,
giving the defense counsel some new material in exchange for the paper in the lawyer's
hand.
Approaching
Dr. Yardley, the lawyer for the defense stated: "Professor, not too long ago, there
was a study which examined the character and composition of a substantial number of
extraterrestrial dust grains, which you have referred to as interplanetary dust particles.
In more than 50 ice samples taken from a core drilled in the ice of Greenland, and,
therefore, representing thousands of years of elapsed time, these researchers found only
an extremely tiny amount of amino acids.
"The
scientists conducting this experimental analysis concluded that amino acids couldn't have
arrived in interplanetary dust particles in amounts which would have any significant
bearing on issues concerning the origin-of-life. How would you respond to this finding,
Dr. Yardley," asked the defense counsel, "in the light of your previous
qualifying provision concerning the availability of exogenous or extraterrestrial organic
materials for entering into solution prior to the formation of a 300-meter ice layer
caused by a faint early sun?"
"Obviously,"
the professor noted, "one's estimates again would have to be revised downward. How
much, and in what way, would depend on what other kinds of organic materials were found in
the analyzed samples."
Shuffling
through the papers in his hand, the lawyer selected another document. "Undoubtedly,
Dr. Yardley," the lawyer said, "you are aware of the fact that a great deal of
the organic materials found in interplanetary dust particles exists in the form of
polycyclic aromatic hydrocarbons and amorphous carbon, both of which offer far less
promise for the origin-of-life question than do amino acids or purine and pyrimidine
nucleic bases. Is my assumption concerning your knowledge correct, Professor?"
"Your
assumption is correct," Dr. Yardley replied. "However," he added,
"some pathways of synthesis have been proposed that permit one to go from amorphous
carbon and polycyclic aromatic carbons to amino acids."
"Yet,"
countered Mr. Tappin, "those pathways are not without their controversial dimensions.
Is it not the case, Dr. Yardley, that other researchers have disputed the proposed
pathways of synthesis to which you are referring?" queried the lawyer.
"That's
right," the professor admitted.
"Dr.
Yardley," inquired Mr. Tappin, "you have testified previously that no one knows,
for sure, about the origins of interplanetary dust particles. Is this correct?"
"Essentially,
yes," the professor confirmed, "although, as I indicated earlier, some
researchers have conjectured these dust particles may have arisen as a result of
asteroid-asteroid collisions."
"However,
Professor," challenged the defense counsel, "would one be justified in saying
there is no proof or evidence in support of such a conjecture?"
"Yes,"
Dr. Yardley agreed, "one would be justified in saying no hard proof or evidence
exists with respect to that conjecture."
"Furthermore,"
inquired Mr. Tappin, "would one also be justified in pointing out that the conjecture
which you have described does not really explain how these dust particles came to contain
different kinds of organic materials?"
"Yes,"
the professor admitted.
"In
point of fact, Dr. Yardley," pressed the defense counsel, "given our ignorance
about the origins of interplanetary dust particles, we really have no reliable and valid
way of projecting backward from current data involving interplanetary dust particles to
what may have been going on during the Archean- era?"
"That's
correct," replied Dr. Yardley.
"In
other words, Professor," continued Mr. Tappin, "we have little or no evidence
concerning either the rates of production of interplanetary dust particles or whether the
levels of mass influx of such particles that are currently observed would have remained
constant across more than 4 billion years, and, therefore, be indicative of the influx of
interplanetary dust particles which may have occurred during the Archean era. Is this
correct, Dr. Yardley?" inquired Mr. Tappin.
"Yes, I
would say so," responded the professor.
"Is it
not also true, Dr. Yardley," probed the defense counsel, "that we have no hard,
rigorous, reliable data on the amount, or kinds, of extraterrestrial organic material that
would have been lost in the Archean era due to: pyrolysis, while in transit through the
atmosphere; or, meteorological and geological ablation after air bursting; or, destruction
as a result of the effects of shock waves or impact with the Earth; or, ultraviolet
decomposition?"
"What
you say is true," Dr. Yardley acknowledged.
"Consequently,
Professor," concluded the defense lawyer, "the mass influx figures you cited
during your direct examination testimony are pure conjecture based on, among other things,
the assumption that everything we observe today with respect to interplanetary dust
particles has remained essentially unchanged for four billion years. Is this
correct?"
"Yes,
it is," the professor agreed, "but I would point out that continuity plays a
fundamental role in many aspects of the natural laws governing physical and chemical
phenomena."
"Dr.
Yardley, would you say there are qualitative differences among, respectively, inorganic
chemistry, organic chemistry and biochemistry?" Mr. Tappin asked.
"I
would say," answered the professor, " there are principles and properties which
are shared in common by these disciplines, as well as areas of qualitative difference in
which properties and principles that are unique, in a sense, to each of these disciplines
do manifest themselves."
"Do you
feel one would be justified," inquired the counsel for the defense, "to say the
problem of accounting for the emergence of life from prebiotic beginnings is, in part, a
reflection of the fact that the transition from organic chemistry to biochemistry
involves, at least at the present time, more unresolved problems of a qualitatively
different kind than one would encounter in making the conceptual transition from inorganic
chemistry to organic chemistry?"
"Yes,"
confirmed the professor, "at the present time, what you have said is the case.
Nonetheless, evolutionary scientists firmly believe the current situation will not last
forever.
"We all
feel," Dr. Yardley added, "that one of these days a researcher or scientist will
demonstrate or discover how the last, unknown steps in the transition from organic
chemistry to biochemistry took place. When this happens, the transition from organic
chemistry will be no more mysterious than is the transition from inorganic chemistry to
organic chemistry."
"Be
that as it may, Professor," responded Mr. Tappin, "let me point out the obvious.
Evolutionary biologists do not currently have such knowledge.
"More
importantly, as far as the present aspect of the cross-examination is concerned, even if
evolutionary biologists did possess such knowledge, certain facts still cannot be denied.
For instance, let us assume there is some continuous set of chemical principles which
allows one to make the transition from organic chemistry to biochemistry through purely
natural processes.
"Nevertheless,
there still are phenomena that occur in biochemical systems which do not take place in the
reactions of systems that are organic but non-biochemical in character. Is this not so,
Professor?" inquired Mr. Tappin.
"Yes,"
confirmed the biologist.
"In
brief, Dr. Yardley," the lawyer summarized, "things do not always remain the
same over time. If they did, we wouldn't be having this debate about why post-prebiotic
times exhibited properties which were not present in prebiotic times.
"What
happens now is not necessarily what was happening in the past. Moreover, what happened in
the past is not necessarily what is happening now.
"This
general principle, if you will, is demonstrated by the qualitative differences between
biochemical processes compared to purely organic ones. This principle also may be
demonstrated by possible differences in the rates of mass influx of interplanetary dust
particles between today and 4 billion years ago.
"Would
you agree, therefore, Dr, Yardley," asked Mr. Tappin, "that although we would
expect the same conditions to exhibit the same properties over time, we cannot expect
different circumstances automatically to lead to the same manifested properties? In fact,
isn't the problem with which we are confronted in this matter of the mass influx rates of
interplanetary dust particles, a variation on this theme?
"We
need to determine the precise nature of the conditions under which an individual is
justified in concluding that the things which are observed today are the same as what
would have been occurring in the Archean era. Is this not part of the problem before us,
Professor?"
"Yes, I
think I could live with your characterization of things," Dr. Yardley stipulated.
Mr. Tappin
began to speak and was interrupted by Judge Arnsberger. "Mr. Tappin, I& #146;m
sorry, but in view of the lateness of the hour, I feel we would be well advised to adjourn
these proceedings for the day.
"I hope
you will agree that the present time seems to offer a natural point of transition in your
cross-examination. In any case, you will be able to pick things up again at 10:00 a.m.
tomorrow morning."
Turning her
attention to the jury, she said: "Please remember, ladies and gentlemen, my previous
instructions to you. You are prohibited from discussing this case either with fellow
jurors or with others whom you may come into contact.
"Court
is adjourned until 10:00 a.m., Thursday morning," announced the judge. Her gavel fell
in confirmation of her words.
