sense and others are not : the former are the impressions conveyed through one or more sense-organs while the latter, which are not data of sense, are those received through the mind itself, as is the case with incorporeal things and all the other presentations which are received by reason. Of sensuous impressions some are from real objects and are accompanied by yielding and assent on our part. But there are also presentations that are appearances and no more, purporting, as it were, to come from real objects. Another division of presentations is into rational and irrational, the former being those of rational creatures, the latter those of the irrational. Those which are rational are processes of thought, while those which are irrational have no name. Again, some of our impressions are scientific, others unscientific : at all events a statue is viewed in a totally different way by the trained eye of a sculptor and by an ordinary man. The Stoics apply the term sense or sensation (omt0i](tls) to three things: (l)the current passing from the principal part of the soul to the senses, (2) apprehension by means of the senses, (3) the apparatus of the sense-organs, in which some persons are deficient. Moreover, the activity of the sense-organs is itself also called sensation. According to them it is by sense that we apprehend black and white, rough and smooth, whereas it is by reason that we apprehend the conclusions of demonstration, for instance the existence of gods and their providence. General notions, indeed, are gained in the following ways : some by direct contact, some by resemblance, some by analogy, some by transposition, sonle by composition, and some by contrariety.