So, this actually comes from our favorite psuedo-scientific psychologist, Carl Jung. It stems from his idea of the gestalt, or world-conciousness. In a similar way that Freud hypothesized the unconscious and subconscious mind that has radical influences on our behavior, Jung hypothesized an 'over-conciouness' from which all conscious beings draw behaviors from. Jung believed that the gestalt explained why migratory birds who were never raised with others of their kind knew to fly south in the winter, or why all humans have myths about floods and snakes, even when there are no floods or snakes present in their eco-system. It is considered mostly horseshit with some interesting philosophical implications, but it still has a dominating presence in the fictional writing world, with 'The Hero's Journey' story type being created from a student of Jung's.

As for science fiction writers specifically, they were in particular obsessed with the idea that we would eventually be able to evolve to communicate within the gestalt itself, thus being able to communicate through thought alone. This kind of thinking, which slotted neatly in with the previous fictional fad of Spiritualism, which also had these elements, but present within a supernatural context, dominated science fiction writing to the point that most authors don't even really know what they are referencing anymore, as the results of extrapolations on this idea (telepathy, clairvoyance, extra-dimensional beings) are larger than the original idea itself.