We are unquestionably "psychic" because we all have psyches (a Greek word for the "soul" in the sense of the seat of emotions, identity, and will). We are not all equally "psychic" in the sense of being able to read others minds or make ours known other than through the ordinary means of communication. Some saints are especially gifted in this regard (St. John Vianney, St. Padre Pio). John's gospel portrays Jesus as know what was in the hearts of his adversaries (e.g., John 2:24). That said, I suspect that the author of Ecclesiastes was not endorsing a quest to develop psychic powers, and definitely would not have thought that trying to "convey messages of grave import" from spirits was wise. It seems much more likely that he meant "the thought is father to the deed" and that people are likely to detect what we are thinking even if we don't say anything directly. That kind of mind-reading happens all the time, because we readily interpret others' body-language, tone of voice, and significant silences.