The telepathic Telosians from Star Trek's 'The Cage'.
A favorite theme of science fiction is the megacephalic alien telepath. At some stage, the supposition goes, intelligent beings reach the stage at which they can communicate with each other by thought alone. The question is whether this is a realistic possibility.
There have been many claims, stemming from parapsychology experiments carried out in laboratories in the United States and Europe since the 1930s, of a weak telepathic ability in some human subjects. Among the best known are those conducted in the 1940s by J. B. Rhine at Duke University and, more recently, by Robert Jahn at Princeton. The wider scientific community has never been convinced by the reported positive results, suspecting instead that the experimental procedures or the statistical handling of data were flawed. The problem remains unresolved. However, it is interesting to consider the case for telepathy purely on evolutionary grounds. If humans do have telepathic abilities (or other paranormal powers, such as telekinesis or clairvoyance) then it is reasonable to suppose that, like our other senses and skills, these developed at some point in the course of our evolution for sound survival-oriented reasons. Clearly, it would be useful to be able to read another's thoughts, or even simply to sense their emotions when they were out of sight. An individual who is more telepathic than his adversary stands a better chance of outflanking him. A group of mildly telepathic hunters, able to communicate without making a noise, stand a better chance of catching their prey. The point is that if some primitive telepathic ability took root in our ancestors, it would have been so valuable that it is surprising not to find it fully developed in modern humans. A counter-argument might be that telepathy is present to a greater extent in other animals and that, as in the case of the olfactory sense, humans have lost the telepathic abilities once enjoyed by their predecessors. A reason for this could be that, following the emergence of a sophisticated spoken language, people had less need to rely on a purely mental (and possibly much less precise) method of conveying thoughts. It seems much more likely, however, in the absence of secure evidence to the contrary, that our species is non-telepathic.
Although it is true that other species on Earth, such as ants and flocking birds, can demonstrate such extraordinarily well-choreographed behavior that it may seem as if they are linked by some form of extrasensory perception, alternative, more mundane explanations are to hand. The question remains whether extraterrestrials, having following an entirely different evolutionary path, may have acquired a telepathic power. One difficulty is that it is not easy to see, in terms of our present scientific knowledge, how biological telepathy could work. That brains produce weak electromagnetic fields is beyond doubt. But even if another brain were sensitive enough to detect these fields, it strains credibility to imagine that any meaningful information could be extracted from them. Far more likely is that an intelligent species might develop a form of telepathy through the use of advanced computer technology. Such a prospect no longer seems fantastic given recent progress in establishing brain-computer links.