I’m currently working on a story of about 23,000 words (that makes it a “novella” or “novelette,” depending on your definition) that has to do with humans from Earth who come in contact with beings on another planet who communicate almost entirely by mental telepathy. Their brains are so big—maybe 50 to 100 times the size and mass of an adult human brain—that they have developed the physical power to send signals to others of their species in the their immediate vicinity. They’re all on the same wavelength, so to speak. These signals are received as communication. Literally. The signals are received as a string of words, in the same way we communicate with a string of words using the vibrations of our vocal cords to send vibrations through a gaseous medium, air. These creatures have no specific organs of communication as we do at all.
All of that got me to thinking. How does one species communicate by mental telepathy to another species if they speak different languages? Is mental telepathy even possible in that situation? A string of words just won’t work because the recipient still won’t understand the meaning of the transmission. But in my story, one of the two main characters is capable of understanding the foreign species. In fact, that’s the whole basis of the story, that humans may be able to contact beings on another world. But, the devil is in the details: how would that work? Science fiction writers might want to take note of this; it could be useful in stories about first contact(s).
I did a little looking around at the concept of “mental telepathy,” and it’s usually defined as the ability to communicate through means not involving talking, reading, or any other standard method. It’s basically a sort of transmission from one mind to another. But that’s as far as it goes. I haven’t found anyone who has actually wondered how it takes place. What is it that’s being transmitted? If someone says she/he can read another person’s mind, what is it they are reading? In my humble, and perhaps somewhat flippant opinion, here’s three possible ways that mental telepathy might actually take place, in order of simplest to most complex.
1. By concepts only. In this method, only broad concepts are actually being transmitted from one to another. The concept of rocket propulsion, for example. Or weightlessness in the vacuum of outer space. The necessity of an atmosphere for life to exist. No actual images are sent, and no details at all.
2. Mind visualization. In this method, actual images are sent. That could transmit a vast amount of information. The image of an Apollo space capsule, inside and out, for example, would tell the recipient—assuming he’s sophisticated in space travel—just what it was like for our species to travel to another heavenly body in the early stages of our space program. The information transmitted would be only in the image itself. Any other information, say, what it was like to live in one of those cramped capsules, would have to be inferred by the recipient. But an Apollo space capsule in one language would be an Apollo space capsule in any other.
3. Transmission of a string of words. This I expect would be the most complicated form of transmission, but would convey the greatest amount of information. That is, of course, what words are designed to do. An image of the Apollo space capsule might give a visitor from another planet a lot of information, but many details he/she (it?) might not understand. Words, description, these would be the most detailed. But the recipient of the mental transmission of a string of words would have to understand the language of the sender to be able to interpret it. and so this method, while highly accurate, might be seriously limited.
I’m not an expert in ESP or mental telepathy, certainly, and I’ve never heard if any of these methods are currently being tested. I’m not sure if mental telepathy really exists outside of science fiction. It’s a controversial subject in real life, but in science fiction the sky’s the limit. If you need mental telepathy in your writing, have a go at one of these types. They seem, to me, to be the most likely modes of transmission of information.