Abstract

Hold up your hands. Say, as you gesture with the right hand, “Here is a hand,” adding, as you gesture with the left, “Here is another hand.” Have you not thereby proved ipso facto the existence of something common to both, viz. the existence of the property being a hand? That depends upon whether the conclusion really follows from these premises – whether from the fact that two things are hands it really follows that something else exists, a common property that makes them so. ¹