More than one scientist has even made use of this form of imagination for the pleasure of developing a purely fanciful notion. Thus Von Baer, supposing that we might perceive the portions of duration in another way, imagines the changes that would result therefrom in our outlook on nature: "Suppose we were able, within the length of a second, to note 10,000 events distinctly, instead of barely 10, as now; if our life were then destined to hold the same number of impressions, it might be 1,000 times as short. We should live less than a month, and personally know nothing of the change of seasons. If born in winter, we should believe in summer as we now believe in the heats of the Carboniferous era. The motions of organic beings would be so slow to our senses as to be inferred, not seen. The sun would stand still in the sky, the moon be almost free from change, and so on. But now reverse the hypothesis and suppose a being to get only one 1,000th part of the sensations that we get in a given time, and consequently to live 1,000 times as long. Winters and summers will be to him like quarters of an hour. Mushrooms and the swifter-growing plants will shoot into being so rapidly as to appear instantaneous creations; annual shrubs will rise and fall from the earth like restlessly boiling water springs; the motions of animals will be as invisible as are to us the movements of bullets and cannonballs; the sun will scour through the sky like a meteor, leaving a fiery trail behind him, etc."[93] The psychologic conditions of this variety of the creative imagination are, then, these: Absence of limitation in time and space, whence the possibility of an endless movement in all directions, and the possibility of filling either with a myriad of dimly-perceived events. These events not being susceptible of clear representation as to their nature and quantity, escaping even a schematic representation, the imagination makes its constructions with substitutes that are, in this case, numbers. IV MUSICAL IMAGINATION Musical imagination deserves a separate monograph. As the task requires, in addition to psychological capacity, a profound knowledge of musical history and technique, it cannot be undertaken here. I purpose only one thing, namely, to show that it has its own individual mark--that it is the type of affective imagination. I have elsewhere[94] attempted to prove that, contrary to the general opinion of psychologists, there exists, in many men at least, an affective memory; that is, a memory of emotions strictly so called, and not merely of the intellectual conditions that caused and accompanied them. I hold that there exists also a form of the creative imagination that is purely emotional--the contents of which are wholly made up of states of mind, dispositions, wants, aspirations, feelings, and emotions of all kinds, and that it is the characteristic of the composer of genius, of the born musician.