Now when it is said that knowledge is essentially knowledge of reality, the statement is parallel to the assertion that a doctor is essentially the doctor of a sick man, and not to the assertion that a doctor is essentially the doctor of a patient. It should mean that that which is capable of being related to a knower as his object is something which is or exists; consequently it cannot be said that since knowledge is of reality, reality must essentially be known. The parallel to the assertion that a doctor is the doctor of a patient is the assertion that knowledge is the knowledge of an object; for just as 'patient' means that which receives treatment from a doctor, so 'object' means that which is known. And here we _can_ go on to make the further parallel assertion that since knowledge is essentially the knowledge of an object, an object is essentially an object of knowledge. Just as 'patient' means a recipient of treatment, or, more accurately, a sick man under treatment, so 'object' means something known, or, more accurately, a reality known. And 'knowledge' and 'object of knowledge', like 'doctor' and 'patient', indicate the same relation, though from different points of view, and, consequently, when we can use the one term, we can use the other. But to say that an object (i. e. a reality known) implies the knowledge of it is not to say that reality implies the knowledge of it, any more than to say that a patient implies a doctor is to say that a sick man implies a doctor.