Hmm... I think purpose is just a way we give meaning to the relationship between object. Like, we see object A serve object B, so we think that the purpose of object A is to serve object B. But this pov can be very rigid, because only a small change in object A or B, or their environment can break this relationship, and the whole purpose turn to ash.
Exp there are object A, C, D, E exist, but they too weak to survive alone, so they all go extinct. Only A remain because it has some uses for B, so B protect it. But overtime for whatever reason, B extinct, but A still remain because it's not weak anymore, or just because the new environment suit A better. A still live on despite it's no longer serve it's "purpose" serving B
Suddenly I think about LSI. They seem to be very good at seeing the connection between object, how every object together maintain a "balance state", every object has it's place, serve its purposes. But because Ne polr, they don't like the idea that object can change and no longer serve it's purpose, and then break the system/balance state, so they try to ensure that every object always seve it's purpose.
But no balance state remain forever. LSI can be very good as system maintainer though.