“Our normal waking consciousness,” William James wrote in his pioneering work on transcendent experiences, “is but one special type of consciousness, whilst all about it, parted from it by the filmiest of screens, there lie potential forms of consciousness entirely different… No account of the universe in its totality can be final which leaves these other forms of consciousness quite disregarded.”

All of us experience altered states of consciousness all the time, without the aid of mind-altering substances. When blood sugar plummets with hunger, a wholly different moodscape takes hold. Under the monthly tempest of hormones, almost a wholly different person can emerge. Every night we feel the edges of consciousness as we slip into the liminal state between wakefulness and sleep. Every day we engage in various delusions and willful blindnesses in order to maintain our self-image, keep our imperfect relationships intact, and guard our deepest hopes from the fearsome fangs of reality.

Given consciousness renders reality what it is, and given this selfsame consciousness is so susceptible to misperceiving reality, it is hardly a wonder that we so easily slip into illusions that appear entirely persuasive and internally coherent — from conspiracy theories to misplaced infatuations to hallucinations. And yet evolution must have had a reason to make us so vulnerable to such deviations from the path of reason — perhaps our misshapen views of reality serve us, perhaps they even save us; perhaps Virginia Woolf was right to write that “illusions are the most valuable and necessary of all things.”

That is what the poetic neurologist Oliver Sacks (July 9, 1933–August 30, 2015) intimates in a lovely passage from his classic Hallucinations (public library):

Humans share much with other animals — the basic needs of food and drink or sleep, for example — but there are additional mental and emotional needs and desires which are perhaps unique to us. To live on a day-to-day basis is insufficient for human beings; we need to transcend, transport, escape; we need meaning, understanding, and explanation; we need to see overall patterns in our lives. We need hope, the sense of a future. And we need freedom (or at least the illusion of freedom) to get beyond ourselves, whether with telescopes and microscopes and our ever-burgeoning technology or in states of mind which allow us to travel to other worlds, to transcend our immediate surroundings. We need detachment of this sort as much as we need engagement in our lives… transports that make our consciousness of time and mortality easier to bear. We seek a holiday from our inner and outer restrictions, a more intense sense of the here and now, the beauty and value of the world we live in.

Complement with the psychology of willful blindness, then revisit Oliver Sacks on consciousness, artificial intelligence, and our search for meaning, the healing power of nature, and the building blocks of personhood.