Is this person,
(a) picking my brain because they really want to know the depths of what I think?
(b) wanting to stir things up a bit (it happens quite a bit) and kind of debate an issue they feel strongly about
(c) are they just wanting a very simple straightforward answer (probably most likely, but not necessarily the INTP's strength).
Also, are they joking and saying things in a lighthearted way or are they looking for a more serious discussion?
I can answer in any one of these ways, but I don't know which they're looking for. I'm looking for context first. In short, it's sometimes very difficult for me to take what I know in my head, the depth of an issue, and present it clearly to someone without some preparation. If I'm preparing a speech, then yes, I will communicate effectively. If it's on the spot and you want a quick answer - then, for the most part, I don't really know how I feel about it