The brain, like a computer, is capable of failure. And hallucinations are often nothing more than a biological version of the famous blue screen of Windows, warning you that you are probably under the influence of drugs, without food, sleep or light for long. But leaving aside these methods, harmful to health, is there any way to hallucinate?
Actually yes. It can be said that the brain is "addicted" to sensations. Exactly, then, when we turn off all our senses and concentrate, we can hear voices, see fantastic places and situations without even leaving the place. This, even, is the basis of meditation: the elimination of all other senses and the mental conversation that almost never stops. This is because the brain is so accustomed to receiving constant stimuli that it does not understand what is happening when they are cut off.
Knowing this, Ganzfeld's experience is easier to understand: by placing a radio on a station with static and covering the eyes with halves of a ping-pong ball, the senses are anesthetized. You can also apply lights (usually red) on the eyes, since the purpose of the halves of the ball is to keep your field of vision homogeneous, as well as the sounding of the sound. Here are some testimonials from those who tried:
"For a long time, I saw nothing but a green haze. It was quite boring, and I thought, 'Ah, what a senseless experiment!'" Then, for a period of time that I can not measure, I went out and was completely absent. I was holding a piece of chalk and writing something mathematical on a blackboard.It was all very clear, but fast, lasting only a few seconds, then disappearing again.The image did not occupy the whole field of vision, it was like looking through a window.
"And I can still see his face, it's very expressive ... I could only see the horse coming, as if from within the clouds, a white horse jumped on me."
"On the right side of the field of vision, a mannequin came in. It was all black and had a long, thin head, broad shoulders with long arms, and a small trunk, and he appeared with his giant vessel-shaped hands. and then returned to the place from which he came, slowly. "
This experience, which has existed for more than 50 years, is currently one of the most famous in the field of parapsychology. It turns out that the hallucinations caused by the absence of stimuli are often cited as the awakening of psychic and paranormal abilities, since in the state people talk to the dead and animals, travel in time and have "revelations", among other things. If it is telepathy or hallucination, only science can respond.
There are other methods, like Ganzfeld's, that work by cheating the brain. One of them, which works in much the same way, is the Purkinje Lights. The scientist, who was one of the founders of neuroscience, discovered as a child this method of seeing colored lights and getting high: with his eyes closed, turn his face towards the Sun, and then swing his (spaced) fingers in front of the view.
Since the eyes will be closed, the sensation will be to "see" a strobe light. With this confusion and without knowing how to interpret what is happening, the brain begins to play random images of its file, producing visions.
So ready, if you're bored and want to have contact with the "spirit world," all you need is a ping pong ball and an old radio, or even the sun and your hand. Good fun!