The common assumptions of physiognomy and phrenology (as we readily detect, though not thus obvious to the minds of their defenders) are these: (1) that there are distinct mental traits, qualities or capacities, which ordinary human intercourse and observation reveal; (2) that these are caused by (or correlated with) prominent developments of parts of the brain; (3) the critical assumption (presumably least explicit of all) that we may accept as established the relation whereby the one, the bodily feature, becomes the index of the other, the mental trait. The assumed principle of relation was plainly empirical, had no warrant in principle. The clue in all such systems was merely a sign or trade-mark displayed, in Lavater’s theological view, by a beneficent Providence to indicate the virtues and vices of men. For phrenology the alleged principle was wholly different. It grew out of the subdivision of the functions of the brain. The evidence, it must be admitted, was sought by approved scientific methods. But the stupendous assumption was made that the presumption in favor of the existence of such specialized brain-areas included a knowledge of their terms, and that their nature was indicated by the specific differences in the observed traits of men; further, that such mental traits, giving rise to or conditioned by marked local development of brain-areas, could be detected in the corresponding prominences of the skull. So supremely unwarranted was this cumulative series of assumptions that the scientific knowledge and procedure associated with its alleged establishment failed to confer upon phrenology any more respectable status or accredited position than were accorded to the far more extravagant assumptions of physiognomy. Clearly, if the assumptions of phrenology held—itself an extravagant supposition—the study of character and temperament would be completely shaped by its conclusions. Since they are neither pertinent nor illuminating, physiological and psychological studies still have a message for the student of human nature.
The chief warrant for a further consideration of the position of Gall and Spurzheim is that their views came into direct contact with the advances in the knowledge of the nervous system, which—as will duly appear—became the requisite for true psychological progress. The central question at issue was whether the brain functioned as a whole, or whether distinct functions could be assigned to its several parts. The former position was defended by Flourens (1794-1867), who maintained that the removal of a part of the brain of a pigeon weakened the general intelligence, but that the intact portion still exercised the complete range of brain-functions, though with diminished efficiency. Gall’s position required a detailed and specialized division of function. He drew attention to the fact that the mutilated pigeon, while retaining physical sight and hearing, became mentally blind to the meaning of what it was clearly able to see, and mentally deaf to the meaning of sounds; he drew attention to the important evidence sup-
