With respect to premise (2), Chatton argues that substances, at least extended substances, cannot make \(p\) true, since there are no such substances on the altar at all. The substance of the body of Christ is present in every consecrated host, on every altar, but unextended while the extended substance of the bread is of course absent. Nor does Chatton think that \(p\) is true of qualities because qualities clearly can naturally exist in the same spatial arrangement at the same time. The very same body or parts of a body can be white and cold all over and at once. So, neither extended substances nor qualities suffice to make \(p\) true. A third entity is necessary and this, Chatton thinks, is a quantity, an entity of which it is true to say that two such entities cannot naturally exist in the same spatial arrangement at the same time. No two quantities, or quantified bodies, can naturally penetrate one another; rather, the one will push out the other. Interestingly, Chatton associates quantity principally with impenetrability rather than extension, conceding to Ockham that substances and qualities may be extended by themselves and irrespective of having any quantity. They cannot, however, be impenetrable without some quantity. This explains why \(p\) refers to two hosts that cannot naturally interpenetrate rather than one whose parts are extended to establish the category of quantity.