I posted on this person's type a long time ago, but I've been thinking about it again...wonder what people think here.
This person strikes me as INTj or ENTj. (Some people have suggested ESTj; I still have trouble seeing him as S because he's so theoretical and anti-materialistic, but I guess I'll continue to consider it.) F or p are impossible for him (except for those who subscribe to the INTp=rational-behaviors school).
Anyhow, here are the cases for both the ITj and ITj points of view; see which one you think is more likely.
Case for INTj: He has very strong opinions on many things...and most of them are very unique. Yet if you listen to him, you'll see that there is a strong logical reason behind his views. He holds his views very confidently. He has always had an interest in politics and in defending what he views as just causes, ever since early childhood. He is strongly anti-materialistic. He knows what he wants and has followed a consistent path all his life. Understanding matters; material possessions mean nothing. It is usually difficult to argue with him.
Case for ENTj: He's a very hard worker, capable of absorbing a lot of material and doing a lot of work in a short time. One of his greatest strengths is general knowledge. Simply put, he "knows everything." This can come in handy in all sorts of practical situations. If you have an unusual tax problem, need to understand something in a foreign language, need to know who the governmental officials are in some remote region of the world, or have an obscure diagnosis and don't know what it means, he will know the precise answers to all of these things, even though they have nothing to do with his field of study or interest. He's a very capable speaker in front of a group. He knows how to be charming and act in the expected way. He's highly assertive and somewhat commanding, and always says exactly what he thinks.
I know this is very little to go on, but does this sound more ITj or ETj?