This article questions the commonly held view that professional ethics is grounded in general ethical principles, in particular, respect for client (or patient) autonomy and beneficence in the treatment of clients (or patients). Although these are admirable as general ethical principles, we argue that there is considerable logical difficulty in applying them to the professional-client relationship. The transition from general principles to professional ethics cannot be made because the intended conclusion applies differently to each of the parties involved, whereas the premise is a general principle that applies equally to both parties. It is widely accepted that professionals are required to recognize that clients or patients possess rights to autonomy that are more than the general rights to personal autonomy accepted in ordinary social life, and that professionals are expected to display beneficence toward their clients that is more than the beneficence expected of anyone in ordinary social life. The comparative component of professional ethics is an intrinsic feature of the professional situation, and thus it cannot be bypassed in working out a proper professional ethics. Thus, we contend, the proper professional treatment of clients or patients has not been explained by appeal to general ethical principles.