Q. When you “towel dry” after a bath or shower, is the towel clean or dirty?

A. The answer to this question likely revolves around what you learned growing up and your belief system in adulthood. Think of whatever you believe as a type of “bias.” The purpose of a shower is to remove dirt (defined as a substance that ordinarily does not belong on your skin) along with dead skin cells. If you start with a towel that has already been used, your brain may say the towel is dirty. If you drop the towel on the floor your brain may think it is now dirty. If you start with an unused towel and it removes dirt and dead skin, your brain may say the towel is now dirty. If your brain believes that dead skin is not dirty because it once belonged to you—and there was no actual dirt to remove—it may say the towel is clean and reusable. What does your brain believe for you?