[Footnote 5: Greek philosophers never understood the dual standard of Truth, and insisted that philosophy was the best preparation for every sort of employment. The people, though generally unwise in political matters, had sense enough not to entrust the care of their temporal interests to philosophers, and so the universal utility of philosophy had few opportunities of being tested. A Macedonian king committed the custody of Corinth and its citadel to a philosopher, Persaeus, who was promptly expelled by Aratus--a mere soldier. Persaeus frequented the schools again, and on the well-worn theme that 'none but a wise man is fit to be a general' being brought up for discussion, he said, 'It is true, and the gods know it, that this maxim of Zeno once pleased me more than all the rest; but I have changed my opinion since I was taught better by the young Sicyonian.'--Plutarch's _Life of Aratus_.] PERCEPTION VII Perception has already been partially defined. So-called 'external objects' are forms excited in our consciousness by pressure of other minds. The great permanent 'world' is due to the action of a cosmic mind with which we are intimately associated throughout our physical life. Objects have a totally different sort of existence from minds, for whereas the latter are--at least relative to objects--self-existent, the former have no existence except during the act of perception. If minds could be all moved asunder from each other the whole objective world would disappear, yet the universe would be as full as before, for sensation occupies no room. The appearances we interpret as distance are due to variations in the pressure or stimulus producing the object. It will be convenient to call the more active mind _Noumenon_, the perceiving mind _Subject_. The mind that is subject on one occasion may be noumenon at another, and conversely. The true antithesis to subject is not object, but noumenon. Object has no antithesis, unless it be nonentity. It is specially to be noticed that an object is not the _cause_ of a sentiment. The knife we see or handle is not the cause of the pain it may inflict if driven into our flesh. Pains and pleasures signify that the noumenal action is powerful enough not only to excite objects in the intellect, but to penetrate inwards and excite sentiments also. It is the noumenon that causes both object and sentiment, as far as the energy exerted is concerned, but the variation of plasma in the subject is also essential to the distinction of object and sentiment.