It only tells him that each does not possess self-contradictory characteristics. A .45 caliber bullet traveling at 850 feet per second won't have a devastating effect on human tissue today and, tomorrow, a peaceful tranquil effect. His only hope is to faithfully follow some omniscient being or some earthly representative claiming a link to such a being. And he has no means of judging between the contradictory claims of all the different witch doctors, all claiming to know the unknowable. But once we accept existence as being what it is, then man's only means of gaining knowledge is reason.
Reason is the non-contradictory identification of the facts of reality.
The Objectivist scholar, David Kelley, has written a book titled The Evidence of the Senses which is a full philosophical defense of man's sensory perceptions. Maybe it is a peace placard. Or perhaps a white bunny. Another conceptual tool, logic, is simply the rules you apply to avoid contradictions. Logic is directly related to reality by the fact that reality is non-contradictory and logic is aimed at identifying reality without contradiction.