In medicine, a patient’s symptoms may be explained by many causes. Experienced doctors train new physicians to keep an open mind and an active list of potential diseases until evidence indicates one. Thoroughness for the patient’s sake is crucial, and skilled doctors quickly change their thinking if indicated by new evidence. The good of the patient far surpasses a doctor’s pride.

In order for a human brain to “see” something external, the data patterns captured by the eyes must be associated with related patterns stored in memory. When they match, the mind accurately perceives things. Thus, prior education greatly influences the correctness of what people see…or are blind to.