Control systems are used in nearly
every form of technology. They take information of some kind and use
it to control the behavior of something else.
An open-loop control system is an
engineering system that takes one or more inputs, processes them, and
produces an output. A closed-loop control system does the same but
includes the output as an additional input so the system can
determine how it is doing.
Open loop systems are generally simple
and are best for tasks that are inexpensive, have other oversight
mechanisms, or are resistant to things going wrong.
Examples:
- Lawn sprinkler timer
- Vehicle steering wheel
Closed loop systems are generally more
complex and are best for tasks that require more care and less
oversight.
Examples:
- Thermostat
- Gyroscopic navigation system
The main value of closed-loop control
systems is that they can monitor their own performance and adjust
behavior to attain a desired output state (subject to physical and
design constraints).
The ideas of open and closed-loop
systems may be seen in other contexts than engineering – with
sufficiently-generous definitions it is difficult to not find them
wherever we may look, in any part of life.
The natural world offers an abundance
of examples.
Consider a hillside full of grasses,
shrubs, and trees. Each plant came from a seed, and each seed lay
dormant until triggered by a convergence of suitable environmental
conditions. Moisture, acidity, temperature, fire, chemistry, and
other conditions had to meet the seed's requirements before it would
sprout. Those conditions were tied to some need or advantage
required by the plant.
And so, even before the first green
shoot pokes through the soil, the plants that grow reflect
information processed through a system. There are perhaps billions
of seeds on that hillside, and only half-a-million or so
self-selected for germination. This is an open-loop system.
The seeds do not germinate in a blank
landscape; shrubs and trees are already growing there. They produce
chemicals to advantage themselves and their offspring. They create
shade and trap moisture. While the seeds germinate in an open-loop
system, the larger ecosystem is closed-loop, its existing state
shaped by the previous and shaping the next. With the addition of
animal system and natural events more levels of open and closed-loops
are added to the total system.
Human affairs may also be viewed
through the lenses of open and closed-loop systems. The economy is a
vast example of a closed-loop system; goods & services are
produced and sold, and the pricing information travels back up the
production chain to inform resource allocation. Even the Soviet
command economy was a closed-loop system, albeit a chunky and
sluggish one; commissars looked at the previous cycle's production
numbers and dictated changes to the next.
Now let's look at the meat of this
article.
Society contains a large number of
open-loop and closed-loop systems. Society is an abstraction of its
components rather than a thing in itself; it is a system of systems.
It is the product of the function & interplay of its component
systems.
A stable and unchanging society is
dominated by closed-loop systems that dampen deviations and keep
society focused on an unmoving “center of gravity.”
A rapidly-changing society is dominated
by open-loop systems as well as closed-loop systems that haven't been
“shook out” or stabilized, or were once stable but no longer
enjoy the environmental conditions under which they were stable.
I argue that we are living in a society
more like the latter than the former.
Modern technological advances are large
enough and rapid enough that society does not reach a stable state
before the next innovation comes along, further exciting an
already-excited system.
Transportation technology is one
example; Uber and other rideshare systems are still expanding, but
may themselves be attacked by autonomous vehicles while driven
vehicles are still replacing taxis.
Birth control is another example; the
consequences of contraceptives and abortion are broadly apparent now,
but society is still reeling and hasn't closed the loop back to the
technology. Perhaps the disruption is so large that no stable state
will be reached before it is wiped out and replaced.
Some things last so briefly that they
do not even get names.
Just because something persists does
not mean that it does so because it is good or beneficial. Some
things persist because they are detrimental. In many healthy systems
things flow easily from one state to another; if something is
noticeably permanent it may be because the flow of things has
experienced some stoppage or restriction that results in an unhealthy
buildup. A traffic jam is one example, extended childhood is
another.
Tradition
I think most of us would agree that
changing all things all the time is a bad idea. We find it desirable
to establish permanence in a facet of our lives we find important.
Knowing the consequences of our actions is a difficult thing; we
cannot poll our great-grandchildren to determine what will have
worked and what will not.
We can however poll our
great-grandparents. What worked for them that can translate to
today? This we call 'tradition' (from the latin tradere, which means
“to hand over,” also the root of 'trade' and 'trader').
Tradition is not necessarily the optimal way of doing things, but for
something to last long enough to become tradition it must demonstrate
a meaningful persistence and therefore may at least serve as a secure
base from which to send out expeditions.
Conclusion
There are very few guarantees in life,
and with a world in such a rapid state of flux as ours it is quite a
task to find things that do not move, or at least move slower.
Seeing the world through the lens of open- and closed-loop systems
has been helpful to me. Hopefully it is helpful to you.
P.S. Here's an interesting article I
found while researching. It didn't fit anywhere but it is a good
read:
http://www.bbc.com/future/story/20190611-how-to-build-something-that-lasts-10000-years?utm_source=pocket-newtab
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