What is thus said of a special group of inquiries by one of the foremost of the younger psychologists, is not without its bearings on all the departments in which psychology can learn. For physiological, or what is technically called psychological, experiment, is co-ordinate with many other sources of information. Much, for instance, is to be learnt by a careful study of language by those who combine sound linguistic knowledge with psychological training. It is in language, spoken and written, that we find at once the great instrument and the great document of the distinctively human progress from a mere _Psyche_ to a mature _Nous_, from Soul to Mind. Whether we look at the varieties of its structure under different ethnological influences, or at the stages of its growth in a nation and an individual, we get light from language on the differentiation and consolidation of ideas. But here again it is easy to lose oneself in the world of etymology, or to be carried away into the enticing questions of real and ideal philology. “The human being of the psychologist,” says Herbart(45), “is the social and civilised human being who stands on the apex of the whole history through which his race has passed. In him is found visibly together all the multiplicity of elements, which, under the name of mental faculties, are regarded as a universal inheritance of humanity. Whether they are originally in conjunction, whether they are originally a multiplicity, is a point on which the facts are silent. The savage and the new-born child give us far less occasion to admire the range of their mind than do the nobler animals. But the psychologists get out of this difficulty by the unwarranted assumption that all the higher mental activities exist potentially in children and savages—though not in the animals—as a rudimentary predisposition or psychical endowment. Of such a nascent intellect, a nascent reason, and nascent moral sense, they find recognisable traces in the scanty similarities which the behaviour of child or savage offers to those of civilised man. We cannot fail to note that in their descriptions they have before them a special state of man, and one which, far from accurately defined, merely follows the general impression made upon us by those beings we name civilised. An extremely fluctuating character inevitably marks this total impression. For there are no general facts:—the genuine psychological documents lie in the momentary states of individuals: and there is an immeasurably long way from these to the height of the universal concept of man in general.”