These types from a hierarchy with ecological systems the highest type. All but
mechanistic systems can incorporate as parts other systems of the same or a
lower type, but not of a higher type; for example, social systems (e.g., society)
may incorporate animate systems (people) and mechanistic systems
(machines), but a mechanistic system cannot incorporate either an animate or
social system. Ecological systems can incorporate systems of all the other
Only animate and social systems can be said to be purposeful.
Systems or their parts are purposeful if, by their choices, they can
produce (a) the same outcome in different ways in the same
environment and (b) different outcomes in the same and different
Now consider each type of system in a bit more detail.