Generalists and higher-rank Mentats were vulnerable to the Mentat Freeze syndrome which sprang from self-doubt. Mentats are taught to transcend the narrowness of specialization but no human being can be entirely free from the element of uncertainty that transcendence implies. Repeated and strenuous questioning of a Mentat's computations did not lead to new computations-those were inferentially determined-but to anxiety about the base of those computations. Senior-rank Mentats were repeatedly warned that wavering was the first step toward the totally disabling Mental-Freeze. That state halted all Mentat functions permanently unless the doubt could be removed and confidence restored
The rehabilitation of frozen Mentats consumed a long process of hypnosis, counseling, and the ultimate rebuilding of a personality strengthened to resist self-doubt. So devastating was Mental-Freeze that the condition, even if recovery was complete, was an insuperable impediment to progress to higher rank. Recuperated fifth and sixth rank Mentats were reduced to appropriate junior levels. Mentats were often haunted by fear of freezing, particularly those who labored alone, far from the protective support of the Order House or other senior Mentats. Self-doubt attacked the solitary Mentat with greater speed and force, and buyers were advised to protect their investment by abstaining from chronic criticism of their Mentats. Several cases are known of Houses trying to freeze a rival's Mentat by feeding false data to undermine his confidence in his data base.
A dangerous strategy for avoiding self-doubt was reliance on absolutes. Mentats naturally preferred known parameters to help establish the limits of inference, and absolutes could increase accuracy by reducing alternatives. Besides lending a feeling of self-assurance, absolutes appealed to Mentats as shortcuts. But the abuse of absolutes was easy and often unnoticed-hypotheses overlooked, options unexplored, fallacious inferences based on wrong assumptions. Grodon Orpar Playt III vigorously countered overdependence on absolutes through exercises in conceived reality with radical differences, e.g. a city without laws, tools designed for feet rather than hands, or a community without division of labor. Such mental gymnastics promoted an awareness of the role of unconscious assumptions and absolutes in Mentat thinking