Uploaded by Stanley Cheung

Thinking in Systems

Thinking in Systems
1: The Basics
More Than the Sum of Its Parts
“An interconnected set of elements that is coherently organized in a way that achieves
Made up of three things: elements, interconnections, and a function / purpose
Examples of systems:
o Personal computer systems made up of programs, and serve the overall purpose of
serving the commands of users
o Sewage system: made of inputs (toilets), pipes, and treatment plants – overall purpose
is to remove waste from habitats
Not everything is a system
o Abstract things with no clearly identified parts that work together is not a system – i.e.,
the word ‘word’
o A water bottle sitting on a desk is not a system – elements not interconnected, and
serve no purpose
Look Beyond Players to the Rules of the Game
How to Identify a System
Can you identify parts?
Do these parts affect each other?
Do these parts produce and effect than what they would if they were not together?
Does this behavior persist over time and a variety of circumstances?
a. Is this a one-time event (e.g., a literal explosion) or not?
Interconnections in a system are the links between nodes (discrete elements)
Computer system example:
o Interconnections, physically, are the wires connecting different computer parts
(memory, GPU, CPU, etc.)
o In software, they are commands from the user, information from programs monitoring
the web / computer used to optimize or update the computer
Function of a system
o Best discovered by seeing how a system behaves
 With that, a tree’s purpose is to grow and persist, because that is the effect that
its system produces
o Systems can have sub-systems that conflict with each other
 The system purpose of a monopoly game is to provide entertainment, but the
subsystem of the players’ goals is to maximize their own enjoyment / to win –
however, one person’s enjoyment could mean conflicting with another person’s
Changing the function or interconnections of a system typically alters it more than if elements
were changed
o If US Presidential votes came only from Congress, or if the purpose of Canadian
government were to perpetuate a communist state
For most systems, elements could be removed and replaced without altering its identity,
such as how a company keeps its identity for hundreds of years after logo, employee,
CEO changes
Bathtubs 101
o In a system: material or information that has built up over time, acts as both a reservoir
and a ‘memory book’ of the system’s history of information flow
o Stocks are connected via inflows and outflows: information flows in and out, and
o Wood is a stock of the tree system – a physical manifestation of the system working
o Stocks take time to change – act as shock absorbers.
 Population of a species takes generations to go up, and usually generations to
go down
o Normally, outflow is dependent on inflow – as inflow stops, outflow will stop
 Stocks are like buffers – make those two flows independent; depending on how
much information / material it has stored up; inflow can stop and there can still
be outflow
o Example – Digestive System
 Waste in intestines is a stock – marker of the food inflows of the past
o Stocks are what a system produces in accumulation – tangible or intangible
How the System Runs Itself – Feedback
Feedback loops
o Mechanism for systems to persist
o Adjusts the inflow / outflow of a stock based on its own state
 Example: Comedian
 A comedian, depending on what jokes the audience reacts too, will alter
their material and delivery
 Helps a system regulate out of extremes; if something is out of control in one
direction, it pushes back in the other
Stabilizing Loops - Balancing Feedback
Balancing feedback loops are equilibrium or goal-seeking loops
o They adjust to meet a particular goal, in one direction or in another depending on the
stock levels, always trying to reach a target
Example: Basketball player practicing their shot
o Based on failures and successes, will adjust their technique until a desirable result is
Runaway Loops – Reinforcing Feedback
Feedback loops that can grow or decay a fraction of itself based on its contents
o Example: Climate change
The more plants die, the more toxic Earth becomes; the more toxic Earth
becomes, the more plants die
A Brief Visit to The Systems Zoo