But early appreciation of complex harmony, and skill in execution, are not enough to produce a great artist, for there must be associated with these things a powerful imagination. While the particular nerves or vessels of the brain with which the imagination is concerned have not been identified, we know by analogy and experience that the exercise of the imagination like that of any other function, is necessary for its development, and according as we allow it to remain in abeyance so we reduce its active value. Clearly also, the seat of the imagination at birth is less rudimentary in some persons than in others. From these facts it would appear that when both the sensory nerve structure and the seat of the imagination are advanced at birth, then we have the basis upon which the precocious genius is built up. With such conditions, patient toil and deep study are alone necessary to produce a sublime artist. Evidently it is extremely rare for the imagination and nerve structure to be together so advanced naturally, but commonly one is more than rudimentary, and the deficiency in the other is compensated for by study.[10]
Of course these observations are general, for there arises the question, to what extent can the senses and imagination be trained? We may well conceive that there is a limit to the development of the sense organs. There must come a period when the optic or aural nerves can be attuned no further; and is the limit equal in all persons? The probability is that it is not. The physical character of the nerves almost certainly varies in different persons, some being able to appreciate more complex harmonies than others, granted the limit of development. This is a point which has to be considered, particularly in the case of music wherein as a rule, the higher the beauty the more complex the combinations of signs. There is a parallel problem to solve in respect of the imagination. We can well believe that there was something abnormal in the imagination of Shakespeare, beyond the probability that in his case the physiological system controlling the seat of the imagination was unusually advanced at birth. It is quite certain that with such a man a given training would result in a far greater advance in the functioning capacity of the imagination, than in the vast majority of persons who might commence the training on apparently equal terms; and he would be able to go further--to surpass the point which might be the limit of development with most persons.