Nevertheless, further analysis of the nature of relative terms, and in particular of knowledge, does not bear out this conclusion. To take the case of a doctor. It is true that if some one is healing, some one else is receiving treatment, i. e. is being healed; and 'patient' being the name for the recipient of treatment, we can express this fact by saying that a doctor is essentially the doctor of a patient. Further, it is true that a recipient of treatment implies a giver of it, as much as a giver of it implies a recipient. Hence we can truly say that since a doctor is the doctor of a patient, a patient is the patient of a doctor, meaning thereby that since that to which a doctor is relative is a patient, a patient must be similarly relative to a doctor. There is, however, another statement which can be made concerning a doctor. We can say that a doctor is a doctor of a human being who is ill, i. e. a sick man. But in this case we cannot go on to say that since a doctor is a doctor of a sick man, a sick man implies or is relative to a doctor. For we mean that the kind of reality capable of being related to a doctor as his patient is a sick man; and from this it does not follow that a reality of this kind does stand in this relation. Doctoring implies a sick man; a sick man does not imply that some one is treating him. We can only say that since a doctor is the doctor of a sick man, a sick man implies the possibility of doctoring. In the former case the terms, viz. 'doctor' and 'patient', are inseparable because they signify the relation in question in different aspects. The relation is one fact which has two inseparable 'sides', and, consequently, the terms must be inseparable which signify the relation respectively from the point of view of the one side and from the point of view of the other. Neither term signifies the nature of the elements which can stand in the relation. In the latter case, however, the terms, viz. 'doctor' and 'sick man', signify respectively the relation in question (in one aspect), and the nature of one of the elements capable of entering into it; consequently they are separable.