Apples into Oranges

It wasn’t exactly insomnia, I just couldn’t get to sleep. Finally I decided I’d had enough lying there in the dark, so I reached for the light switch on the lamp by my bed, remembering first to close my eyes to reduce the shock of the sudden rush of light on my dark-adjusted eyes. Of course I sensed immediately when the light came on in the room, because a small amount of it also came on in my head. There I lay, my eyes closed tight, looking at an internal brightness, where before it was dark. Clearly I was seeing, but there was no object or shape (as in a dream or memory), there was no figure-and-ground, there was only a visual field of light, a volume of luminous energy that was itself the whole visual presentation.

Well of course. Some of the photons were able to make it through the curtain of my eyelids---no surprise there---making contact with my retina, which in turn set off neurons firing as usual, spiking on back to the appropriate centers in my brain. What interests me is how minimal this situation was, beginning with the fact that my eyes were closed. The entire setting for this display of the mystery of consciousness was stripped down and uncomplicated: light radiation made contact with some cells behind my closed eyelids, and that simple physical process caused my conscious awareness to fill with light. It was as though I was seeing, from the inside, the very activation of the photoreceptors on my retina, that I was seeing that process projected into a space behind my closed eyes, a space filled with visible energy. There are the mysteries of the I that sees and the inner eyes that see, but what I’m getting at is even more basic. How does an actual conscious subjective experience come out of the nerve tissue of the brain in the first place?---the so-called ‘hard problem’ of consciousness. A very extreme case of apples and oranges, it would seem.

Francis Crick, co-discoverer with James Watson of the structure of DNA, wrote as the first line in the Preface to The Astonishing Hypothesis, “This book is about the mystery of consciousness---how to explain it in scientific terms.” (The astonishing hypothesis he examines is that all mental experiences “are in fact no more that the behavior of a vast assembly of nerve cells and their associated molecules.”) Later he says in an obvious understatement that neural correlate is a useful term “worth committing to memory”---the very core of the apples I mentioned above and in the title of this post. There’s no doubt that when my retina was bombarded with photons that penetrated the barrier of my eyelids, the first stage of the neural correlate of the light I saw was in play. The physical process, the cascade of neurological events, had begun---and there was light inside.

Of course you might say that an immortal soul is involved in all this somehow, or at least that the old dualism of mind and matter still makes a lot of sense. “There’s all this mental stuff going on in my head, and I don’t mean cells and neurotransmitters,” you might say. We know what you mean, because we understand the meaning of your words clearly. We know exactly what pain feels like and maybe even joy. We know what it’s like to see beauty in the world occasionally, and we know what it’s like to hear news of its tragedies. And definitely we are filled with expectations every time we reach for a light switch.