A good article, highlighting the enormous influence of Plotinus. The Enneads is well worth studying to discern his influence on later thinkers. However, you wrote that "not to be rational is a sin," but this is not a religious idea. Sorry, but in the context, it is religious, although not about "salvation from a deity or a church." I had to laugh — do you need saving from a church? Some, oh yes, I would agree. But the word "religious" applies far beyond Christianity, including the varieties of atheism. I am sure you know that, too.

Anyway, do keep writing, and I plan to buy your book.