"The stability of the internal
medium is a primary condition for the freedom and independence of certain
living bodies in relation to the environment surrounding them."
Claude Bernard, Leçons sur les
Phénomènes de la Vie Communs, 1878-1879
"If we are to understand a
newer and still evolving world; if we are to educate people to live in that
world; if we are to legislate for that world; if we are to abandon categories
and institutions that belong to a vanished world, as it is well-nigh desparate
that we should; then knowledge must be rewritten. Autopoiesis belongs to the
new library."
Stafford Beer, Preface to Autopoiesis, 1980
Autopoiesis is based on the
way living systems address and engage with the domains in which they operate.
This biologically based theory, introduced here, (originated by Maturana and
Varela) defines life as the ability to self-produce, rather than as
(conventionally) the ability to reproduce. Like complexity theory it is a systems perspective, and is applicable to brains and
societies as well as to biology and artificial life. In its original form it was applied to cognition, and replaces an
external objective view of this subject with an internal relativistic
understanding, in terms of an embedded observer.
Only two type of structural
change are possible in living organisms, changes of state that preserve
identity, or disintegration (death). External perturbations trigger the changes
to the organism but do not themselves determine them. The available states of
the organism determine which environmental triggers can be recognised and which
will disintegrate it, but the available states occur by a process of
self-organization. This is the concept of 'structural closure or determinism'
that forms a main theme in autopoietic thinking. Note that this means that we
do not 'map' our environment but just respond to a subset of it - a
simplification required by the cybernetic Law of Requisite Variety.
Instructive interactions
(traditional imposed learning) are said by Maturana to be incapable of being
subjected to scientific procedures. Like molding clay, they leave no trace of
the original structure. Thus the standard neo-Darwinist idea that the
environment imposes order on organisms is at best metaphorical.
For example, the light entering our eye does not 'cause' the photochemical
release that occurs, that mechanism must already exist, light just triggers it.
This ties in with the complexity view that selection acts on systems whose
structure has already self-organized.
An organism undergoes a
history of perturbations from its environment (also seen as
a dynamical system at a higher level, subsuming the organism) which trigger its
own state trajectories. If these triggers are regular,
then the organism also has regular state cycles, if continuously changing then
novel trajectories will occur. If the organism affects (triggers) the
environment in turn then we have the coevolution of two structurally coupled systems.
If these triggers result in
state changes that involve component changes (rather than just interactional
ones) then we have adaptation. This plasticity in structural topology at both
state and component levels is what is called 'structural coupling' and can
operate in both directions. By this process the medium or environmental
organization becomes coordinated with that of the organism. But note that there
is no necessary informational or semantic commonality between the two, each
reacts to the other on its own terms.
The components of the
organism are regarded as a form of autocatalytic set. In other words the
components take in food (lower level components) from the environment and by a
dissipative process (using energy) act on each other in such a way as to
recreate themselves dynamically (unlike machines with fixed parts). This
closure of the system allows it be bounded, to isolate itself from the outside
world and become a self-sustaining constant (homeostatic) system. This definition
of life is far better that the systemic illogicality of defining it as the
reproduction of a passive gene. A living system is a ongoing process that
self-defines and self-maintains its form, reproduction is not a necessary
function of this.
Autopoietic closure is a
systems property and is thus not restricted to biological systems. It gives
Autonomy, Phenomenal Distinctions - an emergent composite level as well as a
part level (these are not logically deducible from each other), Adaptability -
tracking its environment in the present (ontological) and Adaptation -
divergent trajectories of parallel systems (some disintegrate). Thus
reproduction and natural selection is a domain orthogonal to self-producing
'being' or existence itself.
The organism's current
state is due to its history of structural coupling. This base or instinctive
state is a combination of evolutionary and developmental processes. Learning is
also a form of structural coupling, so is indistinguishable from instinct.
Distinctions between evolutionary, developmental and experiential structural
change are thus those of timescale and not of type, and this suggests that they
can be modelled by a common mechanism.
The independence of system
states from environment states allows for decoupling, seen (from outside) as
inappropriate behaviour - often called 'instinct' or 'mistake'. This relates to
systems that are internally dynamically self-consistent (able to follow their
own processes) yet do not act on their environment in a way consistent with
some external understanding. This insight suggests that many alternative and
equally valid 'human systems' can exist without being regarded as 'faulty' - an
idea that has many implications for medical interventionism aimed at 'normalisation'.
This is the structural
coupling between two autopoietic and structurally plastic systems. The
interactions between the two systems are closed on triggers but are open on the
systems that realise them (organisation is independent of the parts that create
it). This means that we can substitute functionally equivalent systems without
affecting the coevolutionary result. Thus artificial lifeforms would be
indistinguishable from natural ones from a behavioural point of view.
Further, because any
individual is organisationally closed and cannot distinguish the source of its
triggers, then the 'reality' that we create bears no relationship to the
external world. We do not model or describe a reality, simply a consensus.
Interacting systems serve as a source of (cybernetically) compensatable
perturbations to each other, but do not share explicitly any external common
reality.
Our discrimination of our
environment (in autopoietic thought) is constrained by structural limitations,
the participant's possible organizational modes. Each mode forms a subset of
the structurally determined set of available actions, and this set changes over
time with the system's structural coupling to the environment (learning,
triggers). Each cognitive entity therefore occupies a niche or
specific 'cognitive domain' closely linked to its own history of structural
coupling. In autopoiesis, calling the brain an 'information processing device'
is patently wrong - that is a description from an external observer viewpoint
and not one experienced by the organism. Information processing is an external
analogy (like attributing emotions to robots) and does not relate to an
internal description of a real symbolic manipulation system.
Language is not therefore
an 'instructive interaction', passively moving information between two
entities, but a mutual orientation of the participants to a common consensus
domain - a linking of their separate cognitive domains. We can only agree as
far as our structural options let us, what an observer assumes (from their
separate domain) to be a universal agreement about reality may be no more than
a common history of structural coupling - a correlation or coordination between
two discrete entities achieved over a period of mutual plastic changes. This
viewpoint generalises language to include many other forms of signalling, and
thus makes all semantics contextual and not absolute.
Six
criteria are given to determine if a system is autopoietic:
1.
Does
the system have identifiable boundaries ?
2.
Does
it have constituent elements or components ?
3.
Is it
mechanistic (subject to cause and effect) ?
4.
Are
the boundaries self-produced ?
5.
Are
the components of the boundaries self-produced ?
6.
Are
the rest of the components self-produced ?
Under these criteria, not
only are biological organisms autopoietic, but so is cognition, society and
many institutions within it.
Coevolution relates to the
two-way interplay between the organism and aspects of its environment and can
occur at various levels. Firstly the organism can affect the physical
environment, by changing the adaptive pressures on itself (e.g. by moving
around, digging holes), thus the physical environment should not be regarded as
a static object. Secondly physical changes in this environment can affect the
organism (e.g. weather changes) leading to adaptation. Most forms of
coevolution however will occur with respect to other organisms, and again there
are several aspects to this. The interactions can be with members of its own
species, either competitive or cooperative, with 'prey' species (lower on the
food chain), with 'predator' species (higher on the food chain), with neutral
species (at any level) and with kin.
All these interactions may
be multi-faceted, i.e. they can affect several interacting values or needs in each organism. A particular set of relevant
interactions, rarely considered, relates to synergic coevolution, where a
number of organisms enter in a mutual arrangement such that the net benefit to
all exceeds their individual costs. The also takes many forms including symbiotic, social and ecological
networks. In general all these effects will be present to some degree in any
complex system, including economic and cultural ones. This necessitates a more
holistic approach if we are to understand which mutual structural changes are
taking place, which niches are being dynamically created, and their relative
stabilities.
Autopoiesis, with its
stress on action within an environment helps us to understand life at all
levels. This relates to the situated or selected self-organization mode of
complexity thought, which considers the coevolution of system and environment.
Whilst autopoiesis usually does not incorporate the complexity concept of
dynamical attractors it uses the same idea of limited
flexibility due to structural connectivity, along with the need to change
structure if we are to develop new modes of behaviour. No mechanism is
suggested however to drive the structural changes and in this respect
complexity thought goes beyond this field, allowing for internal mutation or
recombination to generate emergent options for subsequent testing against
environmental response.