Theme reveal: The puzzle is rotationally symmetrical, except for the circled square . So, if you cut me enough slack for my novice crossword skills, by a long shot, the circled letter may be the so-called "Persian flaw" from the title
I had always wanted to play around with palindromes, and now that I have a little more faith in myself, I can move on to some more serious wordplay
I am barely any philosopher and while I may not entirely agree with the idea, this seemed like an interesting theme for a puzzle, so here we are! :')
Thanks for 5A - ing up with me :')