Turing
came up with a mathematical basis for the process of cell, tissue and organ
differentiation as an example of self-organisation. He published his findings in
a paper called ‘The Chemical Basis of Morphogenesis’ in 1952. It was an era in
which scientists remained loyal to natural selection as being the cause of all
things and the majority of the general public believed in the presence of a
creator God. Through the use of his mathematical models, Turing was able to
demonstrate how random chemical fluctuations which are diffusing and reacting
in a dynamical system, give rise not to disorderly chaos but to an emergence of
structure, pattern and complexity.
Unfortunately,
Turing’s paper did not get the recognition that it warranted, in part as a
consequence of Crick and Watson’s subsequent discovery of how genetic
information may be encoded in DNA and of this seeming to invite a more substantial or credible platform from which to explore the roots of growth and form. It is only in
recent years that this gene-centred view of biology has begun to reconnect with
Turing’s mathematical and chemical one.
In my
previous blog, I wrote that “Cartwright and
Littlewood’s contributions were valuable, but it was to be another 20 years or
so later before chaotic behaviour would be recognised as vital and integral to
all manner of physical systems in the world. The physicist Freeman Dyson has
pointed out that true mathematical originality and innovation can be missed
until later in time when the initial groundwork for the work has been done. He
has said that he remembers being impressed with one of Cartwright’s lectures in
1942 and although could appreciate the beauty and elegance of her discoveries,
was unable to pick up on its potential beyond an immediate context in which the
work was being applied”.
Perhaps there is an element of ‘seeding’ or preparatory work within the sciences
that is a necessary component of being able to recognise an emergent nature or
complexity of pattern or relationship. This may in part explain why Turing’s
appreciation of pattern and form took somewhat of a backseat to Crick and
Watson’s discovery of the double helix. It is interesting to note that some
recent studies have been done to show that a focus on building specialist
knowledge early on in a person’s career can be valuable, but that as time goes
on can become increasingly inflexible and hinder creativity and innovation.
This suggests that it would be wise to encourage for more polymath (a person
with a wide range of knowledge or learning). In an educational environment
which seeks to preserve an historic track record and advocates for demonstrable
routes of excellence, as well as a tendency to ‘follow where the money is’, such encouragement might not be forthcoming. It is beneficial then, for a person to be receptive towards and to engage with their own calling, no matter
where it might lead them.
Turing
had put forward in his paper that “… the system to be
considered consists of a number of chemical substances (morphogens) diffusing
through a mass of tissue of given geometrical form and reacting together within
it.” And, “Such
a system, although it may originally be quite homogenous, may later develop a
pattern or structure due to an instability of the homogenous equilibrium, which
is triggered off by random disturbances.”
Also,
“… a mathematical
model of the growing embryo will be described … the model takes two slightly
different forms. In one of them the cell theory is recognised but the cells are
idealized into geometrical points. In the other the matter of the organism is
imagined as continuously distributed … with either of the models one proceeds
as with a physical theory and defines an entity called ‘the state of the
system’. One then describes how that state is to be determined from the state
at a moment very shortly before. With either model the description of the state
consists of two parts, the mechanical and the chemical.”
Wired
magazine has written “At the heart of any
Turing pattern is a so-called reaction-diffusion system. It consists of an
‘activator’, a chemical that can make more of itself; an ‘inhibitor’, that
slows production of the activator; and a mechanism for diffusing the chemicals.
Many combinations of chemicals can fit this system: What matters isn't their
individual identity, but how they interact, with concentrations oscillating
between high and low and spreading across an area. These simple units then
suffice to produce very complex patterns.”
Science
magazine has written of Turing’s model: “… this model has yet
to gain wide acceptance among experimental biologists. One reason is the gap
between the mathematical simplicity of the model and the complexity of the real
world … concerted efforts to align theoretical models to real-world systems,
however, have begun to bear fruit, pointing to a much broader range of
situations in which the general principles underlying the Turing model might
apply. Gierer and Meinhardt showed that a system needs only to include a
network that combines “a short-range positive feedback with a long-range
negative feedback” to generate a Turing pattern. This is now accepted as the
basic requirement for Turing pattern formation.”
“…
The ability of Turing patterns to regenerate autonomously, even after
experimentally induced disturbances, is also important and of great utility in
explaining the autonomy shown by pattern-forming developmental processes. In
addition, through the tuning of parameters and boundary conditions, the system
underlying Turing pattern formation can generate a nearly limitless variety of
spatial patterns.”
“The
interacting elements need not be limited to molecules, or even to discrete
entities; a circuit of cellular signals will do just as well. There is also no
need for the stimulus to be provided via diffusion; other modes of transmission
can achieve the same end result. Theoretical modelling has shown that a relayed
series of direct cell-to-cell signals can form a wave having properties similar
to one formed by diffusible factors … we are hopeful that with an increased
acceptance among experimental biologists of the principles he first elucidated,
we will see Turing’s mechanism take its place as a model for the understanding
of spatial pattern formation in living systems.”
Darwin
had informed us that pattern is coded for in genes and according to
circumstance, may or may not be passed on. There is something about this theory which appears to regard a person as a bystander or passive
recipient of genetic coding which nature is using for its own purpose. Turing’s
model has at the very least encouraged us to connect with and to explore
pattern and complexity and to appreciate that what at first appears as random
or chaotic is not something to be feared or disregarded but is an essential
component in an emergence of life; a unified field that humanity is very much
part of.
At
the time that Turing was working on his paper on morphogenesis, a Russian
chemist called Boris Belousov was investigating the way that our bodies extract
energy from sugars. He formulated a mixture of chemicals to mimic part of
the process of glucose absorption in the body. The solution started out as
clear and colourless but as he mixed in the final chemical, the whole solution
changed colour before returning to a state of being clear and colourless.
Ordinarily, chemicals can react together but don’t return to a prior state
without intervention. Even more extraordinary was that the solution began to
switch back and forth between being coloured to clear. Belousov repeated his
experiment several times and got the same result. He then submitted a paper of
his findings to a leading Russian scientific journal. The editor of the journal
informed Belousov that his findings were impossible and could not be published
as they had contravened the fundamental laws of physics. Belousov was
discouraged that his work was not going to be taken seriously and gave up on
science altogether, never having encountered Turing’s work.
It is
evident now that instead of contravening the laws of physics, Belousov’s
oscillating chemicals were a real world example of the type of behaviour that
Turing’s equations had predicted. Subsequent experiments have been done by
other scientists to show that if a variation of Belousov’s chemicals are left
unstirred in a Petri dish, instead of simply oscillating, they self-organise
into beautiful structures and patterns. This has been called the
Belousov-Zhabotinsky reaction and is recognised as an example of
non-equilibrium thermodynamics.
Further,
the way that Belousov’s chemicals move as co-ordinated waves is exactly the way
that our heart cells are co-ordinated as they beat. Not only are we able to see
beyond mathematical models and the abstract, but can now see the formation of
patterns of animal skins as well as the very rhythm of cells. Self-organisation
has moved beyond the theoretical and into the functionality of the natural
world.
Since
the days of Newton, the universe has been viewed as a complex and mechanical
device which obeys orderly mathematical rules. This gave it a certain level of
predictability, particularly if you were able to observe and understand the
rules or mathematics of how it was configured to begin with. Physics was viewed
as the new ‘crystal-ball’ but with far more credibility of success (as long as
the initial measurements were accurate). However, the Newtonian worldview was to have an
unexpected consequence, in that the level of confidence and hubris being placed
in it was to generate an extreme reluctance to revisit its underlying theory.
This meant that if something unpredictable arose in results, it was immediately
attributed to an outside force having interfered with an experiment, rather
than being internally generated.
One
of the principal reasons as to why Turing and Belousov had both encountered
inertia in the mainstream scientific community was that for self-organisation
to be accepted, the dominant Newtonian worldview had to collapse; this was
going to be a struggle in the midst of the 1960s, given all the wonders that
science and technology had so convincingly brought to the world.
In my
previous blog I had written about Edward Lorenz, who in the 1960s had run a
weather simulation and found that subsequent testing of the configuration
produced differing outcomes. His contribution greatly influenced the scientific
community to look into what was going on. There was a recognition of the
phenomenon known as chaos, the meaning of which in science is that a system
that is completely described by mathematical equations is more than capable of
being unpredictable without any outside interference, which meant that scientists had
to take self-organisation seriously.
It is
particularly important to distinguish this attribute of there being an
underlying geometric form or order in chaos and which can yield unpredictable
results, from a widespread misapprehension of chaos as referring to a
maelstrom or complexity of phenomenon into which order has to be imposed.
Again, this means that even the most basic of rules or equations, completely
determined, can have outcomes which are completely unpredictable; even the
tiniest difference to a point within a configuration can make a world of
difference and generate something unexpected. ‘The butterfly effect’ as it came
to be known started to show up across different fields. For instance,
mathematical models have been done to show how immeasurably small changes to
the rates at which animals reproduced have had huge consequences on their overall
population over time, but that the numbers could fluctuate wildly and for no
obvious reason.
The
Newtonian worldview of assuming that a mathematical equation could
predict how a system was going to behave was no longer relevant. One ripple
effect of this is that an assumption of simply increasing an amount of
computing power and it being able to solve ever more complicated sets of
equations is false; just as trusting in an academic institution to fill a mind
with knowledge and specialisation in any one subject and assuming that it will
yield intelligence and wisdom within the real world is likely to prove just as
misleading. Observation makes it impossible to know about everything that is
present within a system and with sufficient accuracy so as to remove any
behaviour which gives rise to chaotic solutions. The whole notion of a
clockwork universe has turned out to be an illusion which was based on nothing
but logic and faith.
Where does this leave us in being able to determine reality? If chaos is hardwired into every aspect of the world we live in and we can’t with certainty assume that any given input will yield a particular result, does it require for us to live only in the moment, without preparation or planning for the future? The indications are that we can no longer hold certainty of any records of the past, as the trail of data will not prove to be an accurate determination of events as they occurred. If the past is not a precursor of the present or the future, what does it inform us? Are we sure that we know what intelligence is, if it cannot be measured with accuracy? Has the phenomenon of chaos been misunderstood and undervalued and could it turn out to be our greatest teacher?
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