Shashi,

It strikes me that describing the purpose of a collection of a system of particles is similar to describing yourself as an organism. One could argue the 'organism' does not exist, and it is all just wave functions. That the organism interpretation is not "real".

That would be valid in a certain way. Still the exploitative power we get from the organism interpretations is quite powerful, thus many are comfortable saying it is "real"

But likewise interpreting many biological systems at least as having purposeful parts also has strong explanative power.

It seems in both cases, one can notice the system below is sufficient to explain any given configuration without need for the higher level abstraction, yet in practical terms interpreting wave systems as organisms allows one to make certain predictions about those systems that would not be possible without the higher theory.

Likewise purpose theories of bio systems allow us to make predictions about those systems that are not possible w/o the theory.

It seems purpose is a 'real' as you are! :-)