  Yet intuitively there is an important difference between these constants. We might describe it this way: whereas learning the rules \(R\) is sufficient to impart a full grasp of \(\dq{\exists}\), one could learn the rules \(R'\) without fully understanding what is meant by \(\dq{W}\). To understand \(\dq{W}\) one must know about the human institution of marriage, and that accounts for our feeling that \(\dq{W}\) is not “topic-neutral” enough to be a logical constant. However, this difference between \(\dq{W}\) and \(\dq{\exists}\) cannot be discerned if we talk only of reference or semantic value; it is a difference in the senses of the two expressions.