To insert the contradiction to the above here, I can reliably read the mind of the man who came into my life as a 17-year-old boy twelve years ago, and he mine, under certain circumstances.
And this is not a claim of some supernatural power, or anything of the sort. The impact of our relationship hit us powerfully, and caused us to open our hearts to each other, to the point that we each knew how each other felt and thought and reacted – well enough to make this predictable, including in real time.
A portion of this no doubt resulted from reading of facial expression, and much more derived from sharing of feelings after the fact. But the result is that we each can grasp how the other is reacting, what thoughts are going through each other’s mind, before they are spoken or expressed.
And so, seeing or hearing a given phenomenon in his presence, I know what he is thinking, and similarly he knows the same of me. If not telepathy, it’s close enough to the classic definition to work until SF comes true.
To achieve these results, you must master empathy in order to feel what the other feels, then immerse yourself for extended periods in the feelings and reactions of the other, and under circumstances where total sharing without anything held back is something both are willing to do.
Communication by mind power at a distance? Nearly impossible. We managed it once – we were in separate vehicles travelling together, he made a wrong turn, and we both realized that each would be concerned to get us back together, and therefore concentrated on recognizing what the other would do. And it worked – we stopped at the rest area he expected us to, and I recognized that he would make a U-turn and seek after us, expecting us to wait. We “called” each other’s reactions almost perfectly – the rest area was ten miles further than he’d expected; he went two miles further than I pictured him doing before making the U-turn.
So, yes, it exists – but is probably not anything that will become common public practice. It’s tough emotional and spiritual work to get there, and works only one-on-one, and then only in very limited conditions.