XXXI. (136) Accordingly, in their daily discussions, the company of sophists all over the world annoys the ears of those whom they meet, by discussing with minute accuracy, and expounding precisely, all expressions of a double and ambiguous character, and distinguishing everything which appears to occur to the recollection (and a great many things are fixed deeply in it). Do not these men divide the elements of grammatical speech into consonants and vowels? And do not some men divide speech into their first principles, noun, verb, and conjunction? (137) Do not musicians again divide their own science into rhythm, and part, and melody? and subdivide melody into the chromatic, the enharmonic, and the diatonic species, into the divisions of fourths, and fifths, and the diapason, and into combined and distinct melodies? (138) Do not geometricians divide their science into two generic lines, the straight line, and the circumference? And do not other professors of other arts draw careful distinctions between the species which exist in each of their arts, going accurately through them all from beginning to end? (139) And the whole company of students of philosophy may argue with them on their line of conduct, each going through the studies to which he is accustomed; because, of all existing things some are corporeal, and some incorporeal; some again are inanimate, and some have vitality; some are endowed with, others destitute of reason; some are mortal, others divine; and of mortals some are male, and some female, these being the two divisions of the human race. (140) Again, of incorporeal things, some are perfect and others imperfect; and of perfect things, some are questions and interrogations, others are imprecatory or adjurative; and there are other kinds which have special differences in the elementary principles of such things. Again, there are some things which the dialecticians are accustomed to call actions; (141) and of these some are simple, and others are not simple; and of those which are not simple some are conjunctive, and others are adjunctive in a greater or lesser degree; moreover some are disjunctive, and there are others which come under a similar description. Again, some are true, some are false, some are doubtful; some possible and some impossible; some are corruptible, others incorruptible; some necessary, and others not necessary; some are easy of solution, others difficult to understand; and there are other classifications akin to these. Again, of those which are imperfect there are proximate divisions into what are called categorems and accidents, and other classifications which are subordinate to these.