Darwin's Dangerous Idea (37 page)

is present that makes this the
right
way or
best
way for the coding system to Note that this reasoning does
not
yield the conclusion that double-stranded get designed, given the conditions that obtained.4

DNA
must
develop, for Mother Nature had no advance intention to create All the deepest features of molecular design may be considered from the multicellular life. It just reveals that // double-stranded DNA happens to engineering perspective. On the one hand, consider the fact that macro-begin to develop, it opens up opportunities that are dependent on it. Hence it molecules come in two basic shape categories: symmetrical and
chiral
(with becomes a necessity for those exemplars in the space of all possible life left-handed and right-handed versions). There is a reason why so many forms that avail themselves of it, and if those life forms prevail should be symmetrical:

The selective advantage in a symmetrical complex is enjoyed by all the subunits, while in an asymmetric complex the advantage is only effective 5. Danny Hillis, the creator of the Connection Machine, once told me a story about some in the subunit in which the mutation arises. It is for this reason that we find computer scientists who designed an electronic component for a military application (I so many symmetric structures in biology, "because they were able to make think it was part of a guidance system in airplanes). Their prototype had two circuit the most effective use of their advantage, and thus—
a posteriori
—won the boards, and the top one kept sagging, so, casting about for a quick fix, they spotted a brass doorknob in the lab which had just the right thickness. They took it off its door and jammed it into place between the two circuit boards on the prototype. Sometime later, one of these engineers was called in to look at a problem the military was having with the 4. Eigen suggests that there is a reason why there are four letters, not two, but I am not actual manufactured systems, and found to his amazement that between the circuit going to pass it on. Perhaps you can figure out for yourself what it might be before seeing boards in each unit was a very precisely milled brass duplicate of the original doorknob.

what Eigen says. You already have at your fingertips the relevant principles of engineering This is an Ur-story that has many well-known variations in engineering circles and among to give it a good shot.

evolutionary biologists. For instance, see Primo Levi's amusing account of the mystery of the varnish additive in
The Periodic Table
( 1984).

200 BIOLOGY IS ENGINEERING

Original Sin and the Birth of Meaning
201

over those that do not avail themselves of it, that yields a retroactive en-wished, as the truth that confirms the identify of Adam the Protobacterium.

dorsement of this
raison d'etre
of the DNA language. This is the way evo-We can sharpen up the conditions on being the First Living Thing however lution always discovers reasons—by retroactive endorsement.

we like, but when we then get in our time machine and go back to witness the moment, we find that Adam the Protobacterium, no matter how we have defined it, is probably as undistinguished as Mitochondrial Eve. We know as a matter of logic that there was at least one start that has us as its contin-4. ORIGINAL SIN AND THE BIRTH OF MEANING

uation, but there were probably many false starts that differed
in no interesting way at all
from the one that initiated the winning series. The title of
The road to wisdom?

Adam is, once again, a retrospective honor, and we make a fundamental
Well, it's plain and simple to express:

mistake of reasoning if we ask,
In virtue of what essential difference
is this
Err and err and err again

the beginning of life? There need be no difference at all between Adam and
but less and less and less.

Badam, an atom-for-atom duplicate of Adam who just happened not to have

- Piet Hein

founded anything of note. This is not a
problem
for Darwinian theory; this is a source of its power. As Küppers puts it ( 1990, p. 133), "The fact that we
The solution to the problem of life is seen in the vanishing of this problem.

obviously are not in a position to give a comprehensive definition of the

—LUDWIG WITTGENSTEIN 1922, prop. 6.521

phenomenon 'life' speaks not against but indeed for the possibility of a completely physical explanation of life phenomena."

Once upon a time, there was no mind, and no meaning, and no error, and Exactly the same gratuitous predicament faces anyone who, despairing of no function, and no reasons, and no life. Now all these wonderful things defining something as complicated as life, decides to define the apparently exist. It has to be possible to tell the story of how they all came to exist, and simpler notion of
function
or
teleology.
At exactly what point does function that story must pass, by subtle increments, from elements that manifestly lack make its appearance? Did the very first nucleotides have functions, or did the marvelous properties to elements that manifestly have them. There will they just have causal powers? Did Cairns-Smith's clay crystals exhibit
gen-have to be isthmuses of dubious or controversial or just plain unclas-sifiable
uine
teleological properties, or just
"as if
teological properties? Do gliders in intermediates. All these wonderful properties must have come into existence the Life world have the
function
of locomotion, or do they just move? It gradually, by steps that are barely discernible
even in retrospect.

doesn't make any difference how you legislate the answer; the interesting Recall that in the previous chapter it seemed to be obvious, maybe even a world of functioning mechanisms has to start with mechanisms that "straddle truth of logic, that either there had to be a First Living Thing or there had to the line," and, however far back you place the line, there will be precursors be an infinite regress of Living Things. Neither horn of the dilemma would that differ in arguably nonessential ways from the anointed ones.6

do, of course, and the standard Darwinian solution, which we will see over Nothing complicated enough to be really interesting could have an es-and over again, was this: in its place we described a
finite
regress, in which sence.7 This anti-essentialist theme was recognized by Darwin as a truly the sought-for marvelous property (life, in this case) was acquired by slight, perhaps even imperceptible, amendments or increments.

Here is the most general form of the schema of Darwinian explanation.

The task of getting from the early time when there wasn't any
x
to the later 6. See Bedau 1991 for an exploration of this point that arrives at a somewhat different time when there is lots of
x
is completed by a finite series of steps in which it destination, and Linger 1990 for arguments that go directly counter to it. Linger insists we have conventions such that there must be (on logical grounds) "straddle pairs" in such becomes less and less clear that "there still isn't any
x
here, not really,"

circumstances, such that one is the last item in the series to lack
x
and the other is the through a series of "debatable" steps until we eventually find ourselves on first in the series to have
x.
But as van Inwagen (1993b) observes, a more inviting steps where it is really quite obvious that "of course there is
x,
lots of x" We conclusion is: so much the worse for those conventions.

never draw any lines.

7. These are fighting words for some philosophers. For a clear attempt to salvage a formal Notice what happens in the particular case of the origin of life if we try to logic of essences that specifically addresses the problems raised by the complexity of draw the line. There are a slew of truths—no doubt largely unknowable in artifacts and organisms, see Forbes 1983, 1984. The conclusion I draw from Forbes' work detail by us—any one of which we could "in principle" identify, if we is that it constructs what may be a Pyrrhic victory over Quine's staunch skepticism about essences, but in the process it confirms his underlying warning: contrary to what you might think, there is nothing natural about essentialist thinking; seeing the world through essentialist glasses does not at all make your life easy.

202 BIOLOGY IS ENGINEERING

Original Sin and the Birth of Meaning
203

revolutionary epistemological or metaphysical accompaniment to his science; even gets the cell to carry out its replication; its only contribution is one we should not be surprised by how hard it is for people to swallow. Ever protein factor, specially adapted for the viral RNA. This enzyme does not since Socrates taught Plato (and all the rest of us) how to play the game of become active until a 'password' on the viral RNA is shown. When it sees asking for necessary and sufficient conditions, we have seen the task of this, it reproduces the viral RNA with great efficiency, while ignoring the

"defining your terms" as a proper preamble to all serious investigations, and very much greater number of RNA molecules of the host cell. Conse-this has sent us off on interminable bouts of essence-mongering.8 We
want
to quently the cell is soon flooded with viral RNA. This is packed into the draw lines; we often
need
to draw lines—just so we can terminate or forestall virus' coat protein, which is also synthesized in large quantities, and finally the cell bursts and releases a multitude of progeny virus particles. All this sterile explorations in a timely fashion. Our perceptual systems are even is a programme that runs automatically and is rehearsed down to the genetically designed to force straddling candidates for perception into one smallest detail. [Eigen 1992, p. 40.]

classification or another (Jackendoff 1993), a Good Trick but not a forced move. Darwin shows us that evolution does not need what we need; the real world can get along just fine with the
de facto
divergences that emerge over Love it or hate it, phenomena like this exhibit the heart of the power of the time, leaving lots of emptiness between clusters of actuality.

Darwinian idea. An impersonal, unreflective, robotic, mindless little scrap of We have just glanced briefly at a particularly important instance of this molecular machinery is the ultimate basis of all the agency, and hence characteristic Darwinian explanatory schema, and we should pause to con-meaning, and hence consciousness, in the universe.

firm the effect. Through the microscope of molecular biology, we get to Right from the beginning, the cost of
doing something
is running the risk of witness the birth of
agency,
in the first macromolecules that have enough doing it
wrong,
of making a mistake. Our slogan could be: No taking without complexity to "do things." This is not florid agency—
echt
intentional action, mistaking. The first error that ever was made was a typographical error, a with the representation of reasons, deliberation, reflection, and conscious copying mistake that then became the opportunity for creating a new task decision—but it is the only possible ground from which the seeds of inten-environment ( or fitness landscape ) with a new criterion of right and wrong, tional action could grow. There is something alien and vaguely repellent better and worse. A copying error "counts" as an error here only because there about the quasi-agency we discover at this level—all that purposive hustle is a cost to getting it wrong: termination of the reproductive line at worst, or a and bustle, and yet
there's nobody home.
The molecular machines perform diminution in the capacity to replicate. These are all objective matters, their amazing stunts, obviously exquisitely designed, and just as obviously differences that are there whether or not we look at them, or care about them, none the wiser about what they are doing. Consider this account of the but they bring in their train a new perspective. Before that moment, no activity of an RNA phage, a replicating virus:

opportunity for error existed. However things went, they went neither right nor wrong. Before that moment, there was no stable, predictive way of First of all, the virus needs a material in which to pack and protect its own exercising the option of adopting the perspective from which errors might be genetic information. Secondly, it needs a means of introducing its infor-discerned, and every mistake anybody or anything has ever made since is mation into the host cell. Thirdly, it requires a mechanism for the specific dependent on that original error-making process. In fact, there is strong replication of its information in the presence of a vast excess of host cell selection pressure for making the genetic copying process as high-fidelity as RNA. Finally, it must arrange for the proliferation of its information, a possible, minimizing the likelihood of error. Fortunately, it cannot quite process that usually leads to the destruction of the host cell.... The virus achieve perfection, for if it did, evolution would grind to a halt. This is Original Sin, in scientifically respectable guise. Like the Biblical version, it purports to explain something: the emergence of a new level of phenomena with special characteristics ( meaners in one case, sinners in the other).

8. One of the major themes of the German philosopher Martin Heidegger was that Unlike the Biblical version, it provides an explanation that makes sense; it Socrates is to blame for much of what is wrong with philosophy, because he taught us all does not proclaim itself to be a mysterious fact that one has to take on faith, to demand necessary and sufficient conditions. It cannot be often that Darwin and and it has testable implications.

Heidegger support each other, so the occasion is worth noting. Hubert Dreyfus has long Notice that one of the first fruits of the perspective from which error is maintained (e.g., 1972, 1979) that Artificial Intelligence is based on a failure to appreciate Heidegger's critique of Socrates, and though that may be true of some strands of AI, discernible is a clarification of the concept of a species. When we consider all it is not true of the field in general, which is firmly with Darwin, a claim that I will defend the actual genomic texts that get created in the process of copying, copying, later in this chapter, and in greater detail in chapters 13 to 15.