I've been meaning to post this for a few days, but I discovered recently that Mr. Macris has a blog with some great stuff on it:
A Manifesto in Defense of Simulationism
The Philosophy of Simulationism
The Map is Not the Territory
The above three do an excellent job arguing that the real core and foundation of TTRPGs is simulation of a fictional reality and explaining why people enjoy that. Really good reads and the first I've seen anybody put it into clear philosophical terms.
What Makes an RPG Fun?
Strongly related to the first three, this one is about the necessity of (real) player agency to the enjoyment of TTRPGs.
Player Skill and Character Skill
Syngergizing Player and Character Skill
The above two are about the different ways RPG systems approach the player/character divide and the best way to unify the two. Probably not a new concept to an experienced roleplayer, but his synthesis is the most comprehensive I've seen.
On Wargs and Wolves
On Wights and Wraiths
On Orcs and Ogres
These three are about the nature of various creatures in Tolkien's universe. Apparently one of Mr. Macris' home games using ACKS was set in Middle Earth, so he did his research thoroughly. It's possible the above won't be new to a real Tolkien scholar, but all three had interesting facts of which I was unaware. According to the third article, Tolkien had at least 8(!) different theories on the origin of orcs in his world; I won't spoil the answer but I think Macris makes a good argument on which Tolkien would ultimately have gone with.
That covers most of the good written stuff on his blog. Unfortunately, at least for me who prefers reading to watching, he's mostly switched over to making
YouTube videos now. He also has a
philosophy blog of which I have not read much but the recent articles discussing historical pagan monotheism were interesting.