Subject: phila.9.88  [T-214

Notes on Changing images of the body.

Phila. Libraries, 9/22/88

.fi
My challenge was to relate my experience in molecular
biology to artefacts of the kind that are magnificently
collected in your exhibition.

We have the problem that, as science becomes more
specialized, it becomes more arcane, less accessible to
the layman, however broad his or her general education,
more alienated from everyday experience.

We can all relate this portrait

  Audubon's Osprey and Fish

to the theoretical developments in Darwin's text, and
this text in turn is readable by a large audience.

But as we look in ever more detail what can be found in
that bird, that fish

  Cell

we come in contemporary terms to displays like this:

  DNA sequences -- cover of handbook

or, slightly more colorfully related to the observables
of the laboratory:

  ATCG bands:

As we have gained enormously in scientific precision, we
have lost a good deal in comprehensibility.  At risk also
is that insight into how the world is and can be run that
is essential for authentic participation in a democratic
society.

----------------------

I will argue that DNA is central to the contemporary
image of the body; for 35 years we could assert that the
evolution of man has as its consequence the information
stored in about 2 meters, 3 billion nucleotide units of
DNA.  So I will elaborate a bit on that, on what DNA is
and how it is represented, and then comment briefly on
the extent to which that abstraction is sufficient as an image
of the body.

Let me start again with SLIDES of a cell.  The DNA in
that nucleus is not devoid of colorful connotation:

....

----------------------

Much discussion of the project to sequence the human
genome.  Will that give us the information needed to
prescribe the human body, the implied promise of the
proponents?

There will be a good deal of disillusion and
disappointment if that is taken too literally.  The
billion dollars or so premised as the price tag will give
us something like a million pages of the data I showed
you for the mitochondrial DNA.  Many insights will be
buried in that, insights that can be related to wide
range of other investigation.  But to get a reaosnable
understanding of a single gene and its products is a
$10 MM exercise.  The 100,000 genes will then come to
a staggering $trillion in monetary price tag, without
beginning to embrace the complexity of interactions
among the developmental and regulatory pathways.  Not to
mention the cognitive challenge of dealing with such
orders of complexity.  We should set some priorities among
parts of the genome in allocating resources, when
the comprehensive total is so immense. 


The reductionist-mechanistic approach to the body that
was given great impetus in the last century is the only
heuristic that has given reliable, reproducible knowledge
of the detail of the body.  Ramparts thought impregnable
like the mechanism of gene reproduction have yielded to
straightforward chemical analysis in a fashion that would
have astounded the most enthusiastic cytologists of 50
years ago.  Will we be able to "reduce" every aspect of
human structure and behavior to the elementary rules of
physics and chemistry? Will "consciousness" be as
amenable to physical chemistry as "gene reproduction" has
been?

As a heuristic for further enquiry, I would be inclined
to suggest "yes", but that is not the same as to insist
on reducibility as an article of faith, beyond the point
where it can be tested by tangible, feasible experiments.
The 3 billion units of DNA that "define" the human genome
are sufficient information in the sense that they have
been the object of the evolutionary process, operating in
the actual universe we inhabit, and its laws of physics
and chemistry.  Had we perfect knowledge of those laws,
and a computer of unbounded capacity we might expect to
predict what organism would emerge from any given DNA
complex.  (We would also have to keep in mind that the
DNA must also operate in the context of a preexistent
cell, an object of extraordinary complexity: that cell in
turn is the joint product of its predecessor and its
current DNA content).  Such predictions are the final
test of any scientific theory.  But we have neither that
perfect knowledge nor that boundless computer; and the
solution of nonlinear differential equations with a
100,000 variables is beyond the expectation of
contemporary science.  At this moment, we have a
virtually intractable problem trying to predict just how
a single protein molecule will fold, a sequence of a mere
100 and odd amino acid units.  We therefore ought to
retain a certain humility about how far reductive
analytic science can go in practice in dealing with
systems as complex as the cell, or the brain -- or the
determinants that have to be taken account of before we
can discuss that residual we call free will.  The biological organismic
system must have a certain dissectability and linearity,
or gradual evolution could not have succeeded; but we do
not believe that evolution has always been so smooth.
And we are sometimes puzzled at major discontinuities in
evolutionary change that speak to the contrary.

The occasional scientist who does so is, then,
inappropriately smug and offensive
when he refers to the human body as a "mere machine".
The mechanistic metaphor remains our most powerful guide
to the scientific analysis of the body, seeking an
understanding of it, part by part.  But there is
nothing "mere" about a machine whose complexity still
presents such extraordinary challenges to analysis.
As with our understanding of the cosmos, the metaphor is
an observationally well-founded faith that the universe
is subject to an order of natural law, not demons, ghosts
or demi-gods.  That the cell is DNA and protein subject
to as much chemical understanding as our tools permit,
not a protoplasm imbued with an immanent vital force.  Until we
reach the limits of that understanding we may still enjoy dealing with
our own personalities, and others', in terms that embrace
not only DNA but social organization, intuition,
affect, humanistic and esthetic insight: wonderfully displayed in
that Borgesian Universe we call our Library.

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