 The mind, then, is not destined to rule but to serve, not, however, as the slave of the heart, but as its servant (Bourdeau 2000). Science thus retains an essential function. The dominance of the heart is founded biologically in the ‘positive classification of the eighteen internal functions of the brain, or systematic view of the soul’ (1851, v. 1, 726; E., v. 1, 594–95). The cerebral table distinguishes ten affective forces, five intellectual functions, and three practical qualities; these correspond to the heart, mind, and character, respectively. The functions being ordered according to increasing energy and decreasing dignity, the dominance of the heart can be considered a datum from positive biology. This classification is indispensable for an understanding of the System. It should be mentioned in passing that it shows that the exclusion of psychology does not at all have the meaning usually given to it: Comte had never refused to study man’s higher functions, be they intellectual or moral, but for him this belongs to biology (the classification is sometimes also referred to as the ‘cerebral table’), and so does not require the creation of a new science (1830 (45)). Historically, the conception of the System began with this table, of which different versions were elaborated in succession from 1846. Conceptually, it is the first application of the subjective method, understood as feedback from sociology to the sciences that precede it, starting with the nearest. In this way, the sociologist helps the biologist define the cerebral functions, a task in which, most often, the biologist simply takes up again the divisions of folk psychology. Later, in what has become known as the ‘letters on illness’, Comte likewise proposes a sociological definition of the brain, as the organ through which dead people act on living ones.