A failure to accept the reality of certain body parts that can be known only from deduction was the affective basis for disturbance in abstract thinking in a number of patients. These patients denied the existence of the vagina because it could not be seen. In one case this refusal to acknowledge the reality of the vagina exerted a repressive force against the abstract conceptualization required for body image formation. In this patient a direct connexion could be made between his inability to develop a harmoniously integrated body image and the pronounced disturbance of his reasoning processes. The paper concludes with a review of the literature on ego development as it pertains to the present subject.