People talk without thinking all of the time.

Literally.

If you doubt it, think about this: When you're talking, do you construct each sentence first in your mind, piecing the words together? Or do you simply talk, the words tumbling out in proper sequence and syntax?

For the most part, it's probably the latter. You don't think about each word before you speak it. "Your brain," says Koch, "takes care of that quite well without any conscious effort on your part."

Speaking is, in profound ways, a "nonconscious" behavior. It is a mental operation not directly associated with conscious feelings, sensations or memories. It just sort of happens, seemingly, on its own.

The same is true about much of life. Surprisingly big chunks of it, Koch writes in his new book, "The Quest for Consciousness," happen without us being consciously aware they are happening.

"We all do things every day, virtually every minute, that do not involve conscious thought, from tying our shoes, to driving to work or working out, to cooking dinner," said Koch. "These actions are essentially routine, automatic. You do them without thinking and often have no direct memory of them afterward."