I understand that it's a method that ascribes purposes to things. I have heard people speak very highly and lowly of it. On the one hand people say it has greater explanatory power than cause and effect. On the other, it assumes purpose in a meaningless universe. So which is it? Is it a good framework?
I had a few shower thoughts today regarding this and remembered your thread. Might as well leave it here.
Teleology ascribes a purpose or and end to things, maybe to all things, but more often than not it is ascribed to some deity. The first is what my thoughts were about. As for the second, others have effort posted already so I won't go into it. The second one also addresses elements of spirituality, which I think deserves a place in an imperfect world, and I don't mean imperfect in a capitalist destruction kind of way, just in terms of mortality, disease, love and desires.
Anyhow, I think I'd consider teology ultimately harmful, especially when it comes organic things. SJ Gould and R Lewontin's "Spandrels" is a good paper that challenges the crude or overly keen adaptationist's stance towards ascribing functions and reason to body parts (but not the organism as a whole, whatever that may mean). They call them "just-so stories", but is in fact random, or have no clear cut "reason" as to why such features emerged.
It's inherently undialectical to stop at the seemingly most "whole" unit, and then over analyze so that everything beneath this level have assigned roles and functions to merely sustain this unit.
Of course, when it comes to cases where it's a group consisting of smaller "organisms", each good at doing specific tasks, then are they parts now, or organisms? What is their purpose? To die for their queen and hive? That sounds like just-so stories to me. They are coventions. Not teological ends.
If the organism as a self-contained concept breaks down, we can substitute worker ants and bees with somatic cells and other "sub"-something organisms. Their serving us seems like mutuality rather than because they have assigned purposes. If there are any purposes to be prescribed, as in physiology, it belongs as a dialectical moment, as a concrete object, but not as a permanent and static one.
This can be used for medicine, science, etc. However, to reify its very existence as serving a purpose would mean medicine and biology will one day be "completed" once all of the functions are filled in. To me that is very undialectical.
Relatedly, such an approach is also transphobic (?), as it priorities the goals and purposes of our body parts and amplifies their mechanisms that fulfill such goals. This is because they are reified in our textbooks and in our education, but our feelings and experiences are not factored in with the same priority (well, this is true in western healthcare at least, where treatment of illness is treatment of diseases, not of persons, which is very alienating). Due to our phenomenology being dumbed down for our physiology, healthcare that treats persons are nonexistent, only the dysfunction of said parts.
As for our own teleology, well, if what I've said checks out, then I don't think we have a purpose or end.