Neuroscientist Lisa Barrett has written an interesting little book for a lay audience titled Seven and a Half Lessons about the Brain. In it she discusses, in a folksy, down to earth style, some astonishing and fascinating facts about the brain, some of which raise profound philosophical questions.
It's beyong the scope of Barrett's book for her to explore those questions, but over the next few days I'd like to reflect on some of them here at VP.
For starters, here are a few of those fascinating facts she shares with us:
1. The theory that the brain consists of three layers - a reptilian, a limbic and the neocortex - with three separate functions, is false. So is the Freudian notion that we have an id, ego and superego.
2. The brain consists of 128 billion neurons, more or less, which are all connected to each other in a single massive, flexible network a bit like the world-wide airport system. Just as passengers departing from any airport in the world can land eventually at any other airport, messages from one neuron can connect with any other neuron in the brain.
3. Each neuron can do more than one task and different neurons can all perform similar tasks. If you reach for the mouse of your computer and reach for it again a minute or so later, the two acts could be mediated by entirely different groups of neurons each time even though it was essentially the same action.
4. Each time you recall the same memory, your brain may have assembled it with a different set of neurons. Moreover, brains don't store memories like files in a computer. They reconstruct memories on demand through a mysterious interplay of electricity and chemicals. Because each neuron has the flexibility to perform multiple functions the human brain packs enormous complexity into a relatively small and compact mass.
Items 3. and 4. are especially interesting. At the outset of the book Barrett states that evolution is purposeless, there's no "why" to it. Yet somehow these marvels were produced, she believes, by a mindless, purposeless, random evolutionary process.
Surely, it would be a miracle if the brain were engineered by an intelligent, supernatural Creator, but it would be in a sense a far greater miracle were the brain, an instrument exceedingly more complex than a computer, the accidental product of simple dumb luck.
The more we learn about biology the greater the strain it places on our credulity and common sense to be told with a shrug that marvels like the human brain are just a grand, purposeless result of blind, mindless forces acting by chance.
I suppose that if one can believe that one can believe anything.
