Geese

Why do geese and other birds fly in V-formation? Several different explanations have been suggested.

• aerodynamic advantage
• protection from predators
• communication - they can see one another better
• expresses social relationships - pecking order, dominance

[Sources: Ask a Scientist, New Scientist, Wikipedia] 

Many people seem to think there should be a single correct answer to this kind of question. But POSIWID doesn't make this assumption. Instead of one strong and self-sufficient purpose, we may well find two or three weaker but mutually reinforcing purposes. 

In order to prevent this misunderstanding, perhaps we shouldn't gloss POSIWID as the purpose of a system is what it does but rather a purpose of a system is what it does.

 

See also Constructing POSIWID (April 2022)