^that post probably won't clear things up in the slightest.
As an IN w/Ti you are no doubt constantly thinking about things, and you would consider your views to be quite logically based. However, as for logic, there will be a difference in how important you see it as being. An INTP will tend to want everything well defined, and systematic in a purely logical manner, whereas an INFJ will tend to use logic loosely to provide structure, whereas the real content of the ideas is held intuitively (thus prone to outside misunderstanding). As an introvert with less typical thought patterns, you probably are mostly asocial, however an INFJ will tend to nonetheless have a good intuitive understanding of people's behaviour - it makes intuitive sense - whereas INTPs seem to find a lot of human behaviour to be utterly bewildering. As an INTP, your Pi function is Si meaning you tend to have a more exact/detail based memory, whereas the memory of an INFJ will be almost completely lacking in details, but have an excellent perception of the meaning of the situation that occured, tending to build the details around this like a dream. INTPs tend to perceive new ideas as existing 'out there', whereas INFJs are very much concerned with building up an inner store of ideas, which they are constantly trying to reduce to a more elegant structure - and when a particularly nice restructuing occurs, there will be an A-ha! thought process, which may last quite some time. The INTP will see these ideas manifest, and disappear, whereas to an INFJ, they become a part of him - everything is parsed for meaning through a specific filter, and any new ideas will take quite some time to consolidate and work in to the INFJs worldview. Unless the idea is representative of ideas already known in the INFJ's psyche, the significance will take some time to bear itself out - often an idea will need to be seen once, and then again at a later date for it to be seen as worthwhile. The INTP, while not always being able to put his ideas to words either, will nonetheless tend to have a very precise structure to his thoughts, deliberately systemising his knowledge and brainstorming what it is he knows. The INFJ will have a more fluid model, and thoughts are rarely deliberate, but come to him seemingly randomly, with the flow of these thoughts being thus directed - like someone driving a car, they may adjust the speed and direction, but they have to take in the scenergy already present, and use predefined paths; the content is generally not deliberately chosen.
k I think this is probably pretty long now. I hope something I mentioned helps a bit.
What helped me was comparing my thought patterns to Ti-dominants, and then to Ni-dominants - from reading MBTI forums this should clearly manifest itself, however I advise against using this forum to calibrate for Ni; the INTPs vs. INFJs from INTPforum are probably a safer comparison - and realising that my thoughts were very much Ni. I thought of myself as being rather logical, but when it comes down to it logic is not too big a part of me - it's just a tool I use; all the real insight is held totally in intuition, and just 'comes' to me rather than being deliberately thought out.
INFJ = synthetic philosopher
INTP = analytic philosopher
