Discussions of perception or memory seldom begin by defining a percept or a memory. Discussions of problem solving, however, almost always begin by attempting to define a problem. Yet the term “problem” is in the everyday vocabulary of virtually every adult. When a term that is commonly used must be explicitly defined, usually it is because the meaning that is intended differs from the common usage. The difference may be connotative. For example, the term “relativity” has almost completely different connotations for the theoretical physicist and for the layperson. The difference may also be denotative. For example, the term “flu” denotes different sets of disorders for the epidemiologist and for the layperson. It seems unlikely that two concepts would denote the same things but have different connotations. It is likely, then, but not assured, that the scientific and the lay concepts of a problem denote different things. It is an open question whether or not the two concepts have similar connotations. If the connotations are similar, then we must ask if the problems we, as scientists, study are sufficiently similar to the problems people experience that we can generalize what we learn about how problems are solved and how to assist the process. If the connotations are not similar, the questions are more serious: If our problems are not like people's problems, to what aspect of human experience do they generalize? What fields of scientific inquiry do address problems that people experience?