You can't swing a cat these days without hitting yet another book about the brain. The way we hear it, everything about the mind and the way we live and act and feel—all of this goes on in the brain, and now that we've got all these nifty brain scanning machines we're well on our way to understanding the real nature of life.
It's been pointed out by more than one scientist and philosopher that seeing things happen in brain cells doesn't actually explain conscious experience. And it's also clear that we've jumped the gun on a lot of these issues. To take just one example, lots of time and money has been spent trying to identify and reproduce the pattern-recognition circuits that everyone expected work to turn the stream of visual perception into objects, but one recent study suggests—on the basis of brain scans, it's true—that emotion and intentionality are necessary too. (As the philosopher Fichte said long ago, things appear to us because we have an interest in them.)
But we may be putting too much emphasis on the brain itself. Brains not only aren't minds, it seems possible to act as if you have a mind without any brain at all. This is a passage from my at-some-point-upcoming book on science and religion:
Consider the one-celled amoeba, the only animal that everyone can manage to draw. Amoebas are much more complex than bacteria. Still, they're only single cells, and they're as bereft of nerves and brain as any bacterium. Yet amoebas an talented creatures with a surprising range of abilities. They act intentionally, just like you and me.
In other words, their activity can be focused on a moment-to-moment basis towards something else. In their case this is generally food. They’re omnivores of a sort, living off smaller protozoans as well as algae, and they can draw on a number of hunting techniques. They can vary the stickiness of their outer membrane in order to glide along surfaces. They have a front and a back, although these look the same to us. In a hostile environment like the human body the amoeba that causes dysentery will clean off the telltale surface proteins that mark it as an intruder and push them off its back end, thus evading the host's immune system.
Most surprising of all, amoebas can learn and remember things. If you take a tiny needle and poke one in the front and it will change direction. Poke it in the back it will move away. But if you keep prodding it from behind it will gradually stop responding. It's become habituated to the touch of the needle and it no longer changes behavior when it feels that touch.
It's a stretch to call this full-fledged learning, but habituation is a big step along the path that leads to learning itself. The amoeba normally tries to fle an unfamiliar stimulus. The advantage of this response is obvious; it's much more likely that the stimulus indicates danger rather than food. But every move costs the amoeba precious energy, so it makes equal evolutionary sense for it to ignore any unusual stimulus that's not connected with a threat. Habituation reconciles these two strategies. It's a way of changing behavior once the unexpected turns out not to be the unfortunate.You can't get habituated, though, unless you can recognize that the second, third, and fourth stimuli are the same as the first. You have to compare them with each other. The other stimuli aren't present any more, though, and they can't be experienced directly. Instead, they have to be summoned up and set alongside the present stimulus to see if they match.
Because amoebas can become habituated, we have to assume that they “remember” if a stimulus is one that they've encountered before. They also have to associate those stimuli with the events that came right after them. That’s the only way to find out if anything bad had happened when they encountered them before. The amoeba is thus connecting several things: the needle-prick it’s feeling right now, several needle-pricks that it felt in the past, and what happened (or didn’t happen) after those previous needle-pricks.
This is a complex task, and it demands some capabilities that we would never expect of a mere body, let alone one as primitive as an amoeba’s. I’m not suggesting that amoebas have the kind of conscious memory that we have, and it would be a stretch to say that the amoeba “thinks.” But it not only knows things about the environment, it can add to the things that it knows and keep them in—do we dare to say mind? The amoeba seems to know a great deal and it moves and acts with direction and purpose, all without nerves, sensory organs, or any obvious internal structure. There is probably no better demonstration that knowledge and intentionality, key parts of our notion of mind, are characteristics of the simplest of bodies.