in an existent space separate from it. That being so, his statement, “It is rationally impossible for a thing that can occupy space to exist without being in a direction”—which he has already said is existent—is self-evidently false to reason, and rational people agree that it is false. This is not something obscure to anyone who considers it. Rather, the man has either erred or confused matters in his two premises. He has heard and understood that a body cannot exist without occupying space, and thus every body must have a space. He then calls its space a direction, having previously maintained that direction is something existent. Combining these premises, he concludes that every body depends upon an existent space separate from it.

This error arises from the ambiguity and multiplicity of meanings in the terms “space” and “direction.” He takes one in a particular sense and calls it by the other term, then takes that other term in its other sense. He is thus like someone who says: “Jupiter (al-Mushtarī) has come into conjunction with Saturn. This is the same mushtarī (buyer) who bought the slave and has met with the seller; therefore, the seller is Saturn.” Or he might say: “This is