that there is no such thing as a sign. A sign is not '" apparent on apparent," for .what is apparent needs no sigD : nor is it non-apparent on non-apparent, tor what is revealed by something must needs appear ; nor is it non-apparent on apparent, for that which is to afford the means of apprehending something else must itself be apparent ; nor. lastlv. is it apparent on non-apparent, because the sign, being relative, must be apprehended along with that of which it is the sign, which is not here the case. It follows that nothing uncertain can be apprehended ; for it is through signs that uncertain things are said to be apprehended. 3 Causes, too, they destroy in this way. A cause is something relative ; for it is relative to what can be caused, namely, the effect. But things which are relative are merely objects of thought and have no substantial existence. Therefore a cause can only be an object of thought ; inasmuch as, if it be a cause, it must bring with it that of which it is said to be the cause, otherwise it will not be a cause. Just as a father, in the absence of that in relation to which he is called father, will not be a father, so too with a cause. But that in relation to which the cause is thought of, namely the effect, is not present ; for there is no coming into being or passing away or any other process : therefore there is no such thing as cause. Furthermore, if there is a cause, either bodies are the cause of bodies, or things incorporeal of things incorporeal ; but neither is the case ; therefore there is no such thing as cause. Body in fact could not be the cause of body, inasmuch as both have the same nature. And if either is