Now if the phenomenal orange is a “syntheton”—that is, a product of perceptual synthesis—it clearly cannot be regarded as the _cause_ of the perceptions, through and by means of which it is constructed in mental synthesis. Here popular thought and ordinary language are apt to mislead us. For ordinary language is throughout built upon the popular belief that the objects of the phenomenal world are non-egoistic or independent _existences_, and, moreover, that they are the cause of the perceptions which come into existence when we exercise our senses. This is, however, “to put the car before the horse.” It is to imagine that a structure built up out of the effects of a thing can be the cause of those effects. The phenomenal orange is built up of perceptions instead of being the cause of them. Their cause is therefore to be sought elsewhere than in the phenomenal world of objects. The orange, _qua_ orange, is therefore a “syntheton,” and cannot as such be the cause of the perceptions or “tekmeria,” which go to its synthesis. Let us now look at these perceptions or “tekmeria” from another point of view. They are states of consciousness: they are _thoughts_, if we use this word in its widest extension to embrace everything of which I or my fellow-men or the lower animals are conscious. But my own thoughts are, so long as they last, things that exist. They may be representative of something outside me, but they _are_ also _real existences_. While they last they constitute a part of the universe of existing things. They are, in Dr. Stoney’s terminology, _auta_ (τά ὄντα αὐτά), the very things themselves. An _auto_ (we shall throughout _italicise_ all that belongs to this autic order of existence) is a _thing which really exists_, and in no wise depends on the way we, human minds, may happen to regard it. Our impressions or beliefs about it may be correct or may be erroneous; but the term _auto_ means the _thing itself_. Perceptions, then, inasmuch as they are thoughts, are _auta_. They belong, moreover, to that class of real existences which, since they are woven into the tissue of _minds_ (my mind and the minds of my fellow-men and of the lower animals) are termed _egoistic auta_. They do not remain, however, persistent and unchanged; for perceptions come and go and are modified as they pass like waves over the surface of consciousness. What causes this coming and going, and these changes in the _egoistic auta_ we call perceptions? Not, as we have already seen, the world of phenomenal objects! What then, but other _auta_, which, since they produce effects upon men’s minds through their senses, may be termed _sense-compelling auta_? The phenomenal orange is thus a “syntheton” produced through a synthesis of the effects wrought upon my _mind_ by an autic existence, called by Mr. Stoney the _onto-orange_. The phenomenal orange is, as we have seen, a “protheton”; the _onto-orange_ is its _antitheton_ in the universe of real existences.