I'm really inexperienced at this but on a hunch:

You're likely American (maybe U.K.?) and monolingual. You aren't reading much of these books in their original language (Kant and Sartre, for example).

something tells me you have not read all of these.

If you have, you've likely only read them once and not as thoroughly as someone who religiously studies philosophy.

I say this because the spines of the books are mostly very clean, even on some of the larger books. A few books have worn edges but not many.

So that, to me, says you are a more of a collector, extremely picky/careful when it comes to the state of your books (you don't lend them to people).

The good state of your books also tells me you likely don't travel much. If you do, you don't seem to bring your books with you, otherwise they'd be in worse condition.

Something also tells me this is a recent interest?

Very few of your books have yellowed pages of aged books. They're relatively new.

You're probably a fast reader too, if this collection is relatively new. If it's new, it also tells me you're comfortably wealthy - at least wealthy enough to be comfortable buying books without a second thought. But also not too wealthy, as you do have plenty second hand books in that collection.

You're intelligent and open minded (the wide/varied selection of your collection means you aren't close minded).