419. Whence comes it that the same idea – that of a discovery, for instance – so often suggests itself at the same time to several persons, although they may be at a distance from one another?

"We have already said that, during sleep, spirits communicate with one another; well, when his body awakes, a spirit remembers what he has learned, and the man thinks he has invented it. Thus several persons may find out the same thing at the same time. When you say that an idea is 'in the air,' you employ a figure of speech that is much nearer the truth than you suppose. Every one helps unconsciously to propagate it."

In this way our spirit often reveals to other spirits, without our being aware of it, that which formed the object of our meditations before we went to sleep.

420. Can spirits communicate between themselves when the body is awake?

"A spirit is not enclosed in his body as in a box, but radiates around it in every direction. He can, therefore, hold communication with other spirits even in the waking state, although he does so with more difficulty."

421. How comes it that two persons, perfectly awake, often have the same thought at the same moment?

"It is because two spirits, who are in sympathy, may communicate their thought to each other, even when the body is not asleep."

There is, between spirits, a communication of thoughts which sometimes enables two persons to see and understand one another without having any need of human speech. They may be said to speak the language of spirits.