Intellectual truth is what you "know" because the "knowledge" flows from a logical argument (which may be supported, in part, by "facts"). Real truth is what you know from direct knowledge.
Intellectual truth can be useful; often, it is indispensable. If your father tells you that it is dangerous -- probably life-threatening -- to drive a car into a stone wall at 60 miles and hour, you are well advised to heed your father. You should do so even though he probably doesn't know of the danger from experience or observation.
Indeed, the horizon of useful intellectual truth is vast and seemingly infinite. It encompasses much (but not all) of science, not to mention technology (applied science), and even folklore (where it represents insights gained by trial and error).
Intellectual truth intersects with real truth in many ways. A good example of an intersection is found in counting, which is the foundation of mathematics. We often count real objects that we can sense for ourselves in order to determine such things as whether there are enough eggs to make a cake, enough clean shirts to last until the next laundry day, etc. The act of counting came long before the development of mathematics as a discipline, yet mathematics tells us (among many things) why counting "works" and how to employ it in a variety of ways ranging from the simple and obvious to the dauntingly complex ways (e.g., from addition -- a form of counting -- and multiplication -- a form of addition -- to such abstruse subjects as number theory.
I use counting as an example because it leads to the moral of this post: Intellectual truth is real truth only where it comports with real truth. Intellectual truth which doesn't comport with real truth -- or which hasn't yet been found to be consistent with real truth -- is mere conjecture.
