From the point of view of rehabilitation, two groups of aphasic patients can be recognized. They differ in the severity of the aphasic disorder, in the type of evaluation that can and should be utilized to plan and monitor therapy, and in the therapeutic intervention itself. The therapeutic intervention obviously differs not only between the two groups of patients but also from patient to patient, since no two patients show exactly the same disorder. What I refer to here is a deeper difference, a difference that lies in the rationale underlying the choice of the different implementations. In the first group, the rationale originates in identification of the functional damage, based on an explicit model of the normal function and the choice of coherent and theoretically based exercises; in the second group, no cognitive analysis of the disorder is possible, the theoretical rationale (analysis of conversation) is coarse, and the therapeutic intervention is grossly similar from patient to patient.