Louis doesn't seem like an T, in that he does not resemble other T comedians--he doesn't treat stand-up like an intellectual game. Demetri Martin is very detached, and his routine is full of graphs and absurd drawings. Ricky Gervais is another extremely intellectual comedian, who would often use slideshows and animal facts for laughs. Their work just has a different feel.
On the rare occasion Louis does venture out on a historical/factual limb, I notice he doesn't seem very interested in getting things right. I'm sure he could if he wanted to, but it's just not where he puts his value. He seems to lack respect for the facts. This doesn't seem very T-ish to me at all.
Don't get me wrong, I'm not calling Louis stupid. He is absurd and clever and I love that. But what really makes Louis CK so interesting to me, isn't his intellectual curiousity, it's his moral curiosity. He confronts his assumptions, his unconscious impulses, and puts himself on trial for our comedic pleasure.
He does a great bit about giving soldiers his plane seat in first class.
Every time I see a soldier on a plane, I always think: ‘You know what? I should give him my seat [in first class]. It would be the right thing to do, it would be easy to do, and it would mean a lot to him…I should trade with him.’ I never have, let me make that clear. I’ve never done it once. I’ve had sooo many opportunities. I never even really seriously came close. And here’s the worst part: I still just enjoy the fantasy – for myself to enjoy. I was actually proud of myself…for having thought of it! I was proud! ‘Oh, I am such a sweet man. That is so nice of me! To think of doing that, and then totally never do it.’
I know it's awful to transcribe comedy like that, but I can't find the clip. Louis is brutally self-aware. He captures the ugliest, most pathetic parts of our self, and helps us come to terms with those parts through laughter.
This strikes me as a Ne-Fi/Fi-Ne thing. If you pressed me I would argue he's an ENFP, because I don't think an INFP could laugh about disregarding his values so frequently. I'm not saying ENFP's are morally bankrupt, but I think they would be less loathe to admit their transgressions, especially in the name of performing.
Another reason I suspect he is an ENFP is from watching his evolution as a stand-up. Louis was always very silly, creative and emotional. If you look at his old stand-up bits, they're zany, but they have no teeth. As he got older and accumulated more experience, and (in my mind) became more aware of his auxilary Fi, his humour began to become more personal, darker, more viscerally real. He starts talking about values, family, the foibles of humanity, etc. He went deeper. That's the Louis CK we know and love today. People forget the goofy redhead from the 90s shouting about his peach.
INFP's on the other hand, get broader, and lighter over time. They learn to adapt more, and aren't so annoyingly stubborn when confronted with reality.
I also have always fancied the idea that neurotic/unbalanced N-doms tend to have really gross manifestations of their inferior S. If this were true than Louis' crude, gross-out humour, anxious overeating, impulse shopping, and his slovenly behaviour (I remember Marc Maron interviewing CK on a podcast and they talked about how disgusting Louis's apartment was) would fit.