But what I want to ask is this: INTJ’s that I know have a very strong feeling that I rarely have. The feeling of certainty. Certainty is an emotional state of the brain attached to an idea, just like anger or fear. Now certainty is a feeling I almost never have. I’m almost never certain about anything (actually I’m not even certain about that.) It often happens that INTJ’s I know are are so certain about their idea's that when I argue with them, they end up telling me not only what's wrong with my idea's, but what’s wrong with me.
A feeling based conclusion is not cast in stone. Feelings can change. That is probably why you never feel certain.
On the other hand, logic is absolute. If the reasoning was sound, the conclusion cannot be invalidated simply because someone don't like it. There is no uncertainty unless the conclusion was based on questionable information.