Janus (7 page)

 

 

This is a question which, as W. H. Thorpe recently wrote, 'we are not yet
within sight of being able to answer'.
^[15]
But at least we can approach
it by a rough analogy. Let the chromosomes be represented by the keyboard
of a grand piano -- a very grand piano with a few thousand million keys.
Then each key will represent a gene or hereditary disposition. Every single
cell in the body carries a complete keyboard in its nucleus. But each
specialized cell is only permitted to sound one chord or play one tune,
according to its speciality -- the rest of the keyboard having been
sealed off by scotch-tape.*

 

* This sealing-off process also proceeds step-wise, as the hierarchic
tree branches out into more and more specialized tissues -- see
The Ghost in the Machine, Ch. IX, and below, Part Three.

 

But this analogy immediately poses a further problem:
quis custodiet
ipsos custodes
-- who or what agency decides which keys the cell should
activate at what stage and which should be sealed off? It is at this point
that the basic distinction between fixed codes and adaptable strategies
comes in once again.

 

 

The genetic code, defining the 'rules of the game' of ontogeny, is located
in the
nucleus
of each cell. The nucleus is bounded by a permeable
membrane, which separates it from the surrounding
cell-body
,
consisting of a viscous fluid -- the cytoplasm -- and the varied tribes
of organelles. The cell-body is enclosed in another permeable membrane,
which is surrounded by body-fluids and by other cells, forming a
tissue
;
this, in turn, is in contact with other tissues. In other words, the
genetic code in the cell -- nucleus operates within a
hierarchy of
environments
like a nest of Chinese boxes packed into each other.

 

 

Different types of cells (brain cells, kidney cells, etc.) differ from
each other in the structure and chemistry of their cell-bodies. These
differences are due to the complex interactions between the genetic
keyboard in the chromosomes, the cell-body itself, and its external
environment. The latter contains physico-chemical factors of such extreme
complexity that Waddington coined for it the expression 'epigenetic
landscape'. In this landscape the evolving cell moves like an explorer
in unknown territory. To quote another geneticist, James Bonner,
each embryonic cell must be able to 'test' its neighbour-cells 'for
strangeness or similarity, and in many other ways'.
^[16]
The information thus gathered is then transferred -- 'fed back' --
via the cell-body to the chromosomes, and determines which chords on the
keyboard should be sounded, and which should be temporarily or permanently
sealed off; or, to put it differently, which rules of the game should
be applied to obtain the best results. Hence the significant title of
Waddington's important book on theoretical biology:
The Strategy of
the Genes
. [17]

 

 

Thus ultimately the cell's future depends on its position in the growing
embryo, which determines the strategy of the cell's genes. This has been
dramatically confirmed by experimental embryology: by tampering with the
spatial structure of the embryo in its early stages of development,
the destiny of a whole population of cells could be changed. If at this
early stage the future tail of a newt embryo was grafted into a position
where a leg should be, it grew not into a tail, but into a leg -- surely
an extreme example of a flexible strategy within the rules laid down
by the genetic code. At a later stage of differentiation the tissues
which form the rudiments of future adult organs -- the 'organ-buds' or
'morphogenetic fields' -- behave like autonomous self-regulating holons in
their own right. If at this stage half of the field's tissue is cut away,
the remainder will form, not half an organ, but a complete organ. If the
growing eye-cup is split into several parts, each fragment will form a
smaller, but normal eye.

 

 

There is a significant analogy between the behaviour of embryos at this
advanced stage and that very early, blastular stage, when it still resembles
a hollow ball of cells. When half the blastula of a frog is amputated,
the remainder will develop not into half a frog but a smaller normal
frog; and if a human blastula is split by accident, the result will be
twins or even quadruplets. Thus the holons which at that earliest stage
behave as parts of the potentially
whole organism
manifest the same
self-regulating characteristics as the holons which at a lower (later)
level of the developmental hierarchy are parts of a potential organ; in
both cases (and throughout the intermediary stages) the holons obey the
rules laid down in their genetic code but retain sufficient freedom to
follow one or another developmental pathway, guided by the contingencies
of their environment.

 

 

These self-regulating properties of holons within the growing embryo
ensure that whatever accidental hazards arise during development,
the end-product will be according to norm. In view of the millions and
millions of cells which divide, differentiate, and move about, it must
be assumed that no two embryos, not even identical twins, are formed
in exactly the same way. The self-regulating mechanisms which correct
deviations from the norm and guarantee, so to speak, the end-result,
have been compared to the homeostatic feedback devices in the adult
organism -- so biologists speak of 'developmental homeostasis'.
The future individual is potentially predetermined in the chromosomes
of the fertilized egg; but to translate this blueprint into the finished
product, billions of specialized cells have to be fabricated and moulded
into an integrated structure. It would be absurd to assume that the genes
of that one fertilized egg should contain built-in provisions for each
and every particular contingency which every single one of its fifty-six
generations of daughter-cells might encounter in the process. However,
the problem becomes a little less baffling if we replace the concept of
the 'genetic blueprint', which implies a plan to be rigidly copied, by
the concept of a genetic canon of rules which are fixed, but leave room
for alternative choices, i.e., adaptive strategies guided by feedbacks
and pointers from the environment.

 

 

Needham once coined a phrase about 'the striving of the blastula to grow
into a chicken'. One might call the strategies by which it succeeds
the organism's 'pre-natal skills'. After all, the development of the
embryo and the subsequent maturation of the newborn into an adult are
continuous processes; and we must expect that pre-natal and post-natal
skills have certain basic principles in common with each other and with
other types of hierarchic processes.

 

 

The foregoing section was not intended to describe embryonic development,
only one aspect of it: the combination of fixed rules and variable
strategies, which we also found in instinctive skills (such as
nest-building, etc.) and learnt behaviour (such as language, etc.).
It seems that life in all its manifestations, from morphogenesis to
symbolic thought, is governed by rules of the game which lend it order
and stability but also allow for flexibility; and that these rules,
whether innate or acquired, are represented in coded form on various
levels of the hierarchy, from the genetic code to the structures in the
nervous system associated with symbolic thought
.

 

 

 

10

 

 

Ontogeny and phylogeny, the development of the individual and
the evolution of species, are the two grand
hierarchies
of
becoming. Phylogeny will be discussed in
Part Three
, but an anticipatory remark is
required in our present context of 'rules and strategies'.

 

 

Motor-car manufacturers take it for granted that it would make no sense
to design a new model from scratch; they make use of already existing
sub-assemblies -- engines, batteries, steering systems, etc. -- each of
which has been developed from long previous experience, and then proceed
by small modifications of some of these. Evolution follows a similar
strategy. Compare the front wheels of the latest model with those of an
old vintage car or horse-cart -- they are based on the same principles.
Compare the anatomy of the fore-limbs of reptiles, birds, whales and
man -- they show the same structural design of bones, muscles, nerves
and blood-vessels and are accordingly called 'homologous' organs.

 

 

The functions of legs, wings, flippers and arms are so different that one
would expect them to have quite different designs. Yet they are merely
modifications, strategic adaptations of an already existing structure --
the forelimb of the common reptilian ancestor. Once Nature has taken out
a patent on a vital component or process, she sticks to it with amazing
tenacity: the organ or device has become a stable evolutionary holon.
It is as if she felt compelled to provide unity in variety. Geoffroy
de St Hilaire, one of the pioneers of modern biology, wrote in 1818:
'Vertebrates are built upon one uniform plan -- e.g., the forelimb may be
modified for running, climbing, swimming, or flying, yet the arrangement
of the bones remains the same.'
^[18]
That basic arrangement is part
of the invariant
evolutionary canon
. Its utilization for swimming or
flying is a matter of
evolutionary strategy
.

 

 

This principle holds all along the line, through all the levels of the
evolutionary hierarchy down to the organelles inside the cell, and the DNA
chains in the chromosomes. The same standard models of organelles function
in the cells of mice and men; the same ratchet-device using a contractile
protein serves the motion of amoeba and of the concert-pianist's fingers;
the same four chemical molecules constitute the basic alphabet in which
heredity is encoded throughout the animal and plant kingdoms -- only
the words and phrases formed by them are different for each creature.

 

 

If evolution could only create novelties by starting each time afresh
from the 'primeval soup', the four thousand million years of the earth's
history would not have been long enough to produce even an amoeba.
In a much quoted paper on hierarchic structures, H. G. Simon concluded:
'Complex systems will evolve from simple systems much more rapidly if
there are stable intermediate forms than if there are not. The resulting
complex forms in the former case will be hierarchic. We have only to turn
the argument around to explain the observed predominance of hierarchies
among the complex systems Nature presents to us. Among possible complex
forms, hierarchies are the ones that have the time to evolve.' [19]

 

 

We do not know what forms of life exist on other planets, but we can safely
assume that wherever there is life, it is hierarchically organized.

 

 

 

11

 

 

Neglect of the hierarchic concept, and the failure to make a categorical
distinction between
rules
and
strategies
of behaviour, has caused
much confusion in academic psychology.* Since its primary concern for
the last fifty years was the study of rats in confined spaces ('Skinner
boxes'), this failure is hardly surprising. Yet to any spectator of a
game of football or chess it is at once obvious that each player obeys
rules which determine what he can do, and uses his strategic skills to
decide what he will do. In other words,
the code defines the rules of
the game, strategy decides the course of the game
. The examples cited in
the previous section indicate that this categorical distinction between
rules and strategies is universally applicable to innate and acquired
skills, to the hierarchies which make for social coherence, as well as
to the hierarchies of becoming.

 

* It is interesting to note the intense reluctance of academic
psychologists -- even those who have outgrown the cruder forms of
behaviourist S-R theory -- to come to grips with reality. Thus
Professor G. Miller writes in an article on psycholinguistics:
'As psychologists have learnt to appreciate the complexities of
language, the prospect of reducing it to the laws of behaviour so
carefully studied in lower animals [he means Skinner's rats] has
grown increasingly remote. We have been forced more and more into a
position that non-psychologists probably take for granted, namely,
that language is rule-governed behaviour characterized by enormous
flexibility and freedom of choice. Obvious as this conclusion may
seem, it has important implications for any scientific theory of
language. If rules involve the concepts of right and wrong, they
introduce a normative aspect that has always been avoided in the
natural sciences. . . . To admit that language follows rules seems
to put it outside the range of phenomena accessible to scientific
investigation.' [20]  What a very odd notion of the purpose and
methods of 'scientific investigation'!

 

The nature of the code which regulates behaviour varies of course
according to the nature and level of the hierarchy concerned. Some codes
are innate -- such as the genetic code, or the codes which govern the
instinctive activities of animals; others are acquired by learning --
like the kinetic code in the circuitry of my nervous system which enables
me to ride a bicycle without falling off, or the cognitive code which
defines the rules of playing chess.

 

 

Let us now turn from codes to strategies. To repeat it once more:
the code defines the permitted moves, strategy decides the choice of the
actual move. The next question is: how are these choices made? We might
say that the chess-player's choice is 'free' -- in the sense that it is
not determined by the rule-book. In fact the number of choices confronting
a player in the course of a game of forty moves (while calculating the
potential variations which each move might entail two moves ahead) is
astronomical. But though his choice is 'free' in the above sense of not
being determined by the rules, it is certainly not random. The player
tries to select a 'good' move, which will bring him nearer to a win,
and to avoid a bad move. But the rule-book knows nothing about 'good'
or 'bad' moves. It is, so to speak, ethically neutral. What guides the
player's choice of a hoped-for 'good' move are strategic precepts of a
much higher complexity -- on a higher level of the cognitive hierarchy --
than the simple rules of the game. The rules a child can learn in half
an hour; whereas the strategy is distilled from past experience, the
study of master games and specialized books on chess theory. Generally
we find on successively higher levels of the hierarchy increasingly
complex, more flexible and less predictable patterns of activity with
more degrees of freedom (a larger variety of strategic choices); while
conversely every complex activity, such as writing a letter, branches into
sub-skills which on successively lower levels of the hierarchy become
increasingly mechanical, stereotyped and predictable.* The original
choice of subjects to be discussed in the letter is vast; the next step,
phrasing, still offers a great number of strategic alternatives but is
more restricted by the rules of grammar; the rules of spelling are fixed
with no elbow-room for flexible strategies, and the muscle-contractions
which depress the keys of the typewriter are fully automatized.