An increasing tendency of things to fall to bits
A naive interpretation of the second law of thermodynamics
describes it as an increasing tendency of things to fall to
bits as time passes.
This isn't what the second law actually says - but
the idea does have a sort of intuitive appeal -
since it does seem that many common objects
do eventually fall to bits.
Could it be that this tendency deserves to be described as a
universal aspect of complex systems?
Complex adaptive systems follow lawful behaviour just like
other objects do - though in many cases the rules they
follow may not yet be entirely clear.
These laws are best regarded as additional rules of
thermodynamics designed to deal with complex adaptive
By far the most obvious rule is the statment of how such
systems affect entropy - which I have previously attempted
to describe .
Here I would like to propose that the phenomenon of
senescence is a common feature of a range of complex
adaptive systems - and can be characterised by the
occasional disintegration of such systems.
The suggested rule is different from the second law
of thermodynamics. That also suggests that complex
systems tend to fall to bits - but it can only be
used to make that prediction in closed environments.
The proposed rule does not have that restriction - the
intention is that it can also be applied to self-organising
systems in open environments.
Subjects of senescence
Probably the most familiar senescing objects are
Senescence is common in biology, and - among more complex
organisms - it is nearly universal.
However, other sorts of system also exhibit senescence.
In particular, complex pieces of machinery also exhibit
limited lifespans - and often have lifespan curves
suggesting that progressive degradation followed by
catastrophic collapse is occurring - the signature of
To gives some concrete examples, I claim this is true of
cars, houses, computers, stereos, clocks, motors, hyraulics
Causes of senescence
Why do complex things tend to fall to bits?
It appears that there are many reasons - and that different
ones can apply to different sorts of system:
The role of complexity
Complex systems are often more expensive to replace than
corresponding simpler ones. This makes replacing them
However, they also have more different bits to go wrong. It
is harder to identify the cause of problems - and it
typically require an engineer with more spare parts and
specialised knowledge to fix.
The case of companies
The theory of "universal senescence" suggests that companies
However - as far as I am aware - this theory has never been
It should not be too difficult to test - and the results
may be of some interest.
In theory, a number of mechanisms of senescence ought to
apply to companies.
In particular, companies:
Companies are an interesting case - since most companies are
still very young - and have not directly descended from
other senescing companies. Thus - unlike most complex
organisms with substantial genomes - they are not "built to
senesce". However the theory suggests that they will -
nontheless - exhibit senescence - and that the effect will
probably be big enough and visible enough to be
evident from their lifespan curves.
- ...are vulnerable to environmental damage;
- ...can grow large, become unable to manoeuvre
properly - and then crash;
- can accumulate garbage in their components in the form of
well-disguised dud employees or poorly-designed systems - in
a way that makes the problem difficult to repair;
- ...can reach a size where they become attractive to
predators - and vulnerable to being swallowed up and
destructively digested - in a merger with a larger company;
- ...that have been around longer have increased chances
of attracting parasites - either agents inside the company
who do not have its best interests at heart or externally-
run protection rackets - and the like.
Unfortunately, companies also exhibit the
equivalent of "large infant mortality" - and the effect is a
substantial one. This may act to obscure the effect of
senescence over the lifespan of the majority of
This may make company senescence more difficult to detect.
Can senescence be defended against using modularity? It
seems that - by using a modular design and "unit tests" that
failures in individual modules can be identified, isolated
and repaired - without large-scale failures necessarily
Modularity is - without doubt - a major weapon aganist
However there are a few drawbacks:
- Modularity is a design constraint that conflicts with
efficiency. This is probably why (for example) we don't have
twelve hearts - one heart simply works better;
- Unit tests - and the time spent executing them - also
represent something of a burden;
Also, modularity doesn't completely fix the problem.
There is still the issue of connections between the modules.
These themselves senesce - and may not be so easy to diagnose
There are also the possibilty of unplanned-for failure
scenarios within modules - failures that cause unit tests to
mis-report, failures that knock out whole modules - and so
Forces opposing senescence
There are forces opposing senescence in living systems. These include:
- Repair mechanisms - whose purpose in life is to prevent senescence;
- Self-organising systems - e.g. the process of evolution;
Self-organising processes (such as evolution) represent a
powerful force - which can sometimes have the power to
overcome senescence - and create systems that show no sign
To give an example of this happening, consider the ecosystem
represented by the earth.
Rather than its function degrading and deteriorating over
time, what can be seen is rather the opposite - the system
grows more powerful and technologically sophisticated as
This raises the question of under what circumstances can
complex systems harness self-organising processes - such as
evolution - to avoid senescence.
The answer seems to depend on whether the population
is resource-limited, and on whether it is self-reproducing.
In an environment without resource restrictions, avoiding
senescence seems likely to be relatively easy for an
ecosystem that can replace each of its component parts
and undergo evolution.
Similarly, if an organism doesn't reproduce - and so
doesn't face any competition - then it too should be
able to avoid senescence.
The "interesting" case arises when the population is
resource-limited - and self-reproduces - and so is
ultimately placed in competition with its offspring.
While evolution may be able to stop organisms losing
functionality to senescence, that is no longer sufficient to
prevent them from having their lunch eaten by other
organisms. They have to improve themselves as fast as the
other organisms are doing - and that is eventually likely to
mean improving themselves as fast as the best of the other
organisms is doing.
Unless the population of organisms is very small, this seems
unlikely - since they are placed into competiton with the
best of the rest of the population.
The idea here is that small populations are often
disadvantaged when facing larger ones - through not having
faced so much competiton - and through not having so many
resources or such large populations.
When land bridges form, it is often the smaller population
that is overrun by invaders from the larger one. For
example, this is what happened recently in South America -
and what is happening now with marsupials and placental
- Negligible senescence
There are a few complex organisms that don't senesce.
How do those fit into the idea of "universal senescence"?
Not very well, it must be said. However, they are not very
common - and the theory doesn't suggest that all
long-lived organisms must senesce - it merely provides
reasons why most of them might.
One way to ensure you have good repair mechanisms is
to make sure finding a mate and reproducing is very,
very difficult - so that it can take a very, very long
Under such circumstances, selection will favour very
I am happy to agree that selection is powerful enough to
produce organisms with extremely long lifespans. However
I am inclined to doubt whether that sort of selection
will ever be acting very frequently.
- The Earth
The earth is a complex system - and it shows little sign of
senescence. It is another exception.
The earth currently has several things going for it that
make it unique:
The earth also runs an evolutionary process.
- It hasn't yet managed to reproduce - so it hasn't yet has
much of a taste of the resource conflict between
reproduction and maintenance that the disposable soma theory
- It has no visible competition - and so any problems it
does exhibit are unlikely to be fatal to it.
While the earth doesn't senesce today, I think it is
possible that we will see planetary-scale senescence in the
future - when the ecosystems of planets come up against the
resource conflicts of the "disposable soma" theory.
Under those circumstances, it seems unlikely that
evolutionary process (or similar) will preserve them
indefinitely from being out-competed by other organisms who
are participating in a larger evolutionary process.
- Bright Light