There are many different types of hallucinations relating to our senses and perceptions that can provide interesting insights into how the mind works.

Auditory hallucinations are the most common form. Two main types exist; elementary, such as persistent sounds in the case of tinnitus, and complex. This latter group further divides into two subcategories. The first encompasses hallucinations that include the auditory equivalent of Charles Bonnet syndrome known as Musical Ear syndrome, where fragments of music manifest without any external source. The second involves the hearing of goading or malicious voices and is most often correlated with diagnoses of paranoid schizophrenia.

Apart from hallucinations that owe their appearance to natural causes such as illness or neurochemical misfiring, some arise as a result of physical injury or amputation. Phantom Limb syndrome hallucinations can include sensations, sometimes painful, that are felt as though real despite no longer having a physical location in the body.

The accidental discovery of LSD by Albert Hofmann in 1943, and subsequent counter-cultural exposition of psychedelic drugs beginning in the 1960s that continues to this day has brought the notion of hallucination more generally into the collective awareness. Psychedelic drugs, both naturally-occurring and laboratory-synthesized, are a means by which human consciousness can be perturbed at will through ingesting a substance, often with unpredictable, hallucinatory results. The book Poisoner in Chief by Stephen Kinzer reveals how the US government conducted its notorious CIA mind control research program, MK-ULTRA, under Sydney Gottleib, which administered LSD to many unwitting subjects. In popular culture, people who read Aldous Huxley’s “The Doors of Perception“ (1954) became entranced by his vivid elucidations of hallucinations, notably the perception of colour, and sought to similarly explore the numinous realms he described. Consider his mescalin-induced observations of the books on his bookshelf:

“Like flowers, they glowed, when I looked at them, with brighter colors, a profounder significance. Red books, like rubies; emerald books; books bound in white jade; books of agate; of aquamarine; of yellow topaz; lapis lazuli books whose color was so intense, so intrinsically meaningful, that they seemed on the point of leaving the shelves to thrust themselves more insistently on my attention” (1954, p. 19).

It should be no wonder too, that with the help of ebullient characters including Timothy Leary, Ken Kesey and his “Band of Merry Pranksters”, not to mention use by countless artists and musicians, why LSD and its psychedelic counterparts were instrumental in the 1960s counter-cultural revolution.

In addition to enabling the perception of colour as hyper-saturated, sometimes even with meaning, facets of the psychedelic experience commonly include changes to how time and space are felt. For instance, three-dimensional reality can have the appearance of being reduced down to flat, two-dimensional planes. In cases where sufficient quantity of a drug is ingested, for example psilocybin, the active ingredient in magic mushrooms, one may even feel part of a projection of the physical surroundings oneself, or sense the presence of some other entity. Popular psychonaut and ethnobotanist Terence McKenna, who described encounters with extraterrestrial “machine elves” after ingesting a “heroic dose” of five dried grams of psilocybe cubensis in silent darkness, argued that the discovery of this hallucinogen by our ancestors on the African savanna was antecedent to the development of advanced human consciousness.

With magic mushrooms and other psychedelic drugs such as DMT, the experimenter can experience being transported to celestial worlds, encounter alien and animistic life forms, or arrive at colossal, transcendental insights about life and the universe, far beyond ordinary imagination. Often, experiences in this vein leave people feeling irrevocably changed for the better; suddenly at peace with themselves and the world. Under recent medically well-documented circumstances, psychedelic drugs such as psilocybin have been used in controlled settings to help treat the symptoms of trauma, and issues along the anxiety spectrum. In some cases, people have garnered keen insight into the ultimate effects of their behaviour, and have wound up completely changing course in life, or miraculously recovering from a substance addiction. Psychedelic experiences can, however, be frightening for some, and in a very few cases permanent psychiatric damage has been reported, perhaps as a result of not paying important attention to “set” and “setting” when taking the drug.

The experiences of hallucinations, from the extreme mind-boggling, never-seen-before imagery and landscapes, to ones caused by injury, disease, or neurological misfiring, all point to the fact that the human mind is a truly complex organ. An antennae-like perceptual device itself that is charged with managing the sense gate data of its several constituent inputs and making it all cohere for us. The signals are many and come from deep within as well as out beyond. Like dreams, hallucinations force us to suspend beliefs about the mind as an isolated, independently-operating black box. If we can expand our definition of its throughput to include all of the data crossing its sense thresholds, beyond even what can be consciously perceived, is it that far a stretch to suggest that our minds themselves extend well beyond their apparent cranial capacities?

Huxley, A. (1954) The Doors of Perception. New York, United States: Harper Collins

Kinzer, S. (2019) Poisoner in Chief. New York, United States: Henry Holt and Co.