I enjoy learning knowledge just for the sake of gaining knowledge alone. I tend to have a deep curiosity toward lots of things in general and learning new knowledge helped to satisfy those curiosity of mine.
I consider myself a life-long learner. It's always good to have knowledge about all sorts of things.
My learning leans towards human science. Anything that slices up the mind interests me. This may qualify as a purpose.
Honestly I don't put conscious thoughts into systematic learning as in getting a degree. Whatever I find interesting I'd dive in. The important thing is to never stop looking for interesting something to stimulate mind.
Epistemology is fun. Learning about our knowledge of knowledge of knowledge of knowledge (etc).
My favourite is stuff that is really theoretical but also practical. Like personality theory (Adler, Erikson, the Existentialists), Ethics, that kind of shit. I thought I'd like metaphysics, which is like purely intellectual mental gymnastics, but my overwhelming reaction was always oh my god who cares?! Like thinking about whether causality is actually a thing (and not just a form of conjunction without 'cause'), or if time is composed of like individual time slices, how does this shit improve your quality of life at all? I'd rather try to read my fortune by looking at the cracks in my bathroom tile.
Knowledge yessssss! Love this topic. Could talk about it for hours, but in a nutshell...
So, of course, I'm an incredibly conceptual thinker (INFJ after all, strong T for an INFJ). Whenever I learn something, I almost immediately extract the general concept and framework it. The facts and the details... gone. I actually have a VERY difficult time remembering facts unless I'm actively focusing/actively remembering them or if there's a strong emotional connection.
The great thing about being so abstract is that you develop a conceptual blueprint that you can place over pretty much anything. And if it's deep and if you're adept at moving through it, you can delve into deep conversations on topics you actually know very little about.
That said, I do believe that the abstract should be based on the concrete and that the abstract has very concrete consequences. IMO, the abstract is the undercurrent that moves a concrete world.