The authors of this book present a concept of neurosis and its treatment based upon the psychological concepts of Aristotelian-Thomistic philosophy. They state that rational psychology offers an intellectually more satisfying and acceptable explanation for Freud's observations than his theories do. The first several chapters discuss the psychology of the normal individual. In these chapters, the groundwork is laid for a subsequent discussion of psychopathology and treatment. Man's sensory life is distinguished between cognitive life or sense knowledge and appetitive life or sense arousal. Sensory knowledge is obtained via external and internal senses. A common sense, or sensus cummunis, blends various sensations into a unified whole. This common sense, plus imagination, instinct and memory are the internal senses. They are subject to the evaluation of the estimative power of the intellect as regards their practical fulfillment as "desirable" or "potentially harmful. " The appetitive life is determined by either pleasure or utility drives. The pleasure drive is somewhat analogous to the libido of analytic literature; the utility drive represents the means by which a desire may be obtained or avoided. The emotions of the utility drive involve either hope and courage or their opposites, despair and fear.