Such descriptions may be valid, but they are not definitions of mental health—and their precise meaning is not
always clear. One can agree with the above characterizations, in a general way; but they are not adequate to the
problem. What must be provided is a fundamental principle, an identification of the essence of mental health. Such
characteristics as the above are effects or consequences. But what is their cause?
The key to the problem of defining the concepts of health and disease, as they pertain to man's mind, consists of
placing the issue in a biological context—of remembering that man is a living organism, and that the concepts of
health and disease are inextricably linked to the basic alternative confronting all organisms: the issue of life and
death.
In the sphere of physical health and disease, this fact is clearly recognized. A healthy body is one whose organs
function efficiently in maintaining the life of the organism; a diseased body is one whose organs do not. The health
or disease of any part of man's body is judged by the standard of how well or poorly it performs its survival-
function. Life is the standard of judgment.
No other rational standard is possible. It is only the alternative of life or death that makes the concept of health or of
disease meaningful or possible. An inanimate object can be neither well nor ill; the concepts are not applicable.
Without life as the standard, the concepts of health and disease are not intelligible.
Just as medical science evaluates a man's body by the standard of whether or not his body is functioning as man's
life requires, so the science of psychology must employ the same standard in appraising the health or disease of a
man's mind. The health of a man's mind must be judged by how well that mind performs its biological function.
What is the biological function of mind? Cognition—evaluation—and the regulation of action.
The basic function of man's consciousness is cognition, i.e., awareness and knowledge of the facts of reality. Since
man must act, his survival requires that he apprehend reality, so that he may regulate his behavior accordingly.
The crucial connecting link between cognition and the regulation of action is evaluation. Evaluation is the process
of identifying the beneficial or harmful relationship of some aspect of reality