I’ve had two hallucinations in my life (reading this book actually made me remember them!). The first was actually a delusion. I remember being very young, with a high fever, lying down on the couch with a cold towel on my forehead. Suddenly, it felt as if a speeding train was approaching my brain, faster and faster towards my head, receding, approaching; or, a beam of light violently approaching me so fast that I thought I would go insane; the feeling was slightly comparable to when you get the bed spins after too much drinking. I barely remember anything from my early childhood, except this. With high fevers, delusions are common, as the book talks about.
Second, I was lying down in my college dorm room bed, in between waking and sleep. Suddenly I felt a very strong presence entering the room, and then a spiritual, ecstatic joy. I kept my eyes closed; I was afraid the feeling was going to end. Eventually it faded, but the feeling of joy stayed with me all day. When we think of hallucinations, we usually think about visual hallucinations and seeing pink elephants, but kinesthetic hallucinations, as I had—feeling a presence—are quite common too. In fact, the book portrays an astonishing variety of all the things people see, hear, smell, and feel—that are not really there.
In fact, the whole point of the book is that hallucinations are much more common, natural, and “normal” than most people think. They have been part of history, of religion, and art. Part of the problem is stigma. Hallucinating does not necessarily mean you are “crazy” or even that the cause is psychological in nature (as is schizophrenia, for example). Most people have had some sort of hallucination once in their life. It is common in people that go blind, for example, to have visual hallucinations. Many people enjoy them and think of it as a “gift” directly from their brain (which is perhaps compensating for the loss of vision by providing another visual world).
And of course the most entertaining chapter is where Oliver Sacks talks about all his self-inflicted LSD hallucinations and the many other drugs he tried in the 60’s and 70’s that caused beautiful and horrible trips—only for medical reasons, of course. Yes of course.
Still, I didn’t enjoy the book as much as I wanted to. It’s too descriptive and encyclopedic, and not explanatory, theoretical, speculative. Yes, I want the hallucinations; but even more I want to know why they occur, why we have them, how they evolved, etc. Besides occasionally making a speculations that “this hallucination explains this religious phenomenon," it fell short on that account.