peared sweet to one man might seem bitter to another man; thus, that there could be no truth beyond “what any one troweth;” any assertion might be true for the individual who made it, and not for any one besides. Aristotle argues against this sceptical theory, (‘Metaphys.’ III. iv.); in spite of minor fluctuations in the subjective perceptions of individuals he finds ground for truth and certainty in the consensus of the human race, and in science which deals with universal propositions obtained by reason out of particular perceptions.
As usual, there is a great contrast between the correctness of his general philosophy of the senses and that of his particular scientific theory of the operation of each sense. While the world has made no advance upon the one—which was arrived at by mere force of thought—the other, lacking the aid of instruments and accumulated experience, has been wholly left behind, and appears infantile when compared with the discoveries of a Helmholtz. The following is a specimen of Aristotle’s physiology of the senses: “Do sensations travel to us?” he asks. “Certainly,” is the reply; “the nearest person will catch an odour first. Sound is perceived after the blow which caused it. The letters of which words are composed get disarranged by being carried in the air (!), and hence people fail to hear what has been said at a distance. Each sense has its own proper vehicle. Water is the vehicle of sight, air of sound, fire of smell, earth of touch and taste. Sensations are not bodies, but motions or affections of the vehicle or medium along
