Extra-sensory perception hasn't been proven has it? I know that there have been studies on it, but some of them were found to be flawed later. But it is so difficult to prove something that's so difficult to measure.
These tests on extra-sensory perception mostly involve guessing games, where participants are asked to guess an object or word written behind a piece of paper. But there are many things to account for. People may receive cues or hints from body language or otherwise to make an intelligent guess. So how do we know for certain whether this ability is a sign of extra-sensory perception or not? It's tricky.