189. DEGREES OF HEIGHT ARE HOMOGENEOUS, AND ONE IS FROM THE OTHER IN SUCCESSION LIKE END, CAUSE, AND EFFECT. As degrees of breadth, that is continuous degrees, are like gradations from light to shade, from heat to cold, from hard to soft, from dense to rare, from thick to thin, and so forth; and as these degrees are known from sensuous and ocular experience, while degrees of height, or discrete degrees, are not, the latter kind shall be treated of especially in this Part; for without a knowledge of these degrees, causes cannot be seen. It is known indeed that end, cause, and effect follow in order, like prior, subsequent, and final; also that the end begets the cause, and, through the cause, the effect, that the end may have form; also about these many other things are known; and yet to know these things, and not to see them in their applications to existing things is simply to know abstractions, which remain in the memory only so long as the mind is in analytical ideas from metaphysical thought. From this it is that although end, cause, and effect advance according to discrete degrees, little if anything is known in the world about these degrees. For a mere knowledge of abstractions is like an airy something which flies away; but when abstractions are applied to such things as are in the world, they become like what is seen with the eyes on earth, and remains in the memory.