THE THIN LINE BETWEEN SCIENCE AND SCIENTOLOGY:

The brain is not the mind. It is probably impossible to look at a map of brain activity and predict or even understand the emotions, reactions, hopes and desires of the mind.

The first basic problem is that regions of the brain handle a wide variety of different tasks. As Sally Satel and Scott O. Lilienfeld explained in their compelling and highly readable book, "Brainwashed: The Seductive Appeal of Mindless Neuroscience," you put somebody in an fMRI machine and see that the amygdala or the insula lights up during certain activities. But the amygdala lights up during fear, happiness, novelty, anger or sexual arousal (at least in women). The insula plays a role in processing trust, insight, empathy, aversion and disbelief. So what are you really looking at?

Then there is the problem that one activity is usually distributed over many different places in the brain. In his book, "Brain Imaging," the Yale biophysicist Robert Shulman notes that we have this useful concept, "working memory," but the activity described by this concept is widely distributed across at least 30 regions of the brain. Furthermore, there appears to be no dispersed pattern of activation that we can look at and say, "That person is experiencing hatred."

Then there is the problem that one action can arise out of many different brain states and the same event can trigger many different brain reactions. As the eminent psychologist Jerome Kagan has argued, you may order the same salad, but your brain activity will look different, depending on whether you are drunk or sober, alert or tired.

Then, as Kagan also notes, there is the problem of meaning. A glass of water may be more meaningful to you when you are dying of thirst than when you are not. Your lover means more than your friend. It's as hard to study neurons and understand the flavors of meaning as it is to study Shakespeare's spelling and understand the passions aroused by Macbeth.

Finally, there is the problem of agency, the problem that bedevils all methods that mimic physics to predict human behavior. People are smokers one day but quit the next. People can change their brains in unique and unpredictable ways by shifting the patterns of their attention.

What Satel and Lilienfeld call "neurocentrism" is an effort to take the indeterminacy of life and reduce it to measurable, scientific categories.

Follow @brothersjudd