We cannot, therefore, throw upon Professor James the responsibility of finding in consciousness the data for our belief in personal identity if we do not accept his natural-science conception of psychology. Whatever view we take of it, we all agree with him in holding that a description of the facts of consciousness is a part of its business. And if among the facts to be described are the data that lead to the belief in personal identity, our obligation to find them is as strong as his is. When the data are found, of course, psychology, as natural science, must find the coexisting brain-states of which they are the mental correlates, but the data that will do for us will do for Professor James.
From this point of view it is evident that another of Professor Ladd's criticisms fails to hit the mark. "We are told in general," he says, "that psychology only assumes that thoughts successively occur and that they (the thoughts) know objects in a world which the psychologist also knows. But how thoughts can know 'objects in a world,' and in what respect the psychologist's knowledge of this world differs from the knowledge of the objects in this world, by his thoughts; and how the knowledge of the psychologist is going to be identified by himself with the knowledge of the objects by the psychologist's thought; — we find it difficult to understand as a matter of cerebral psychology." Are any of these questions more difficult to answer from Professor James's point of view than from Professor Ladd's? According to Professor James — and I think Professor Ladd would agree with him — the first one, "how thoughts can know objects in a world," is a question that psychology has nothing to do with: that is the business of the Theory of Knowledge. But every one of them presses upon Professor Ladd with his conception of psychology quite as strongly as upon Professor James. Both admit that a description of the facts of consciousness is a part of the business of psychology, and when the facts are correctly described Professor Ladd's questions will be answered. No possible or conceivable insight into the metaphysical ground of consciousness can alter in the slightest degree the facts of consciousness. They are what they are no matter how they came to be what they are. Also they are what they are whether Professor James can or cannot find the brain-states that coexist with them. When he can tell us the brain-states that invariably coexist with them, he can explain them in the scientific sense; when Professor Ladd can tell us their metaphysical cause, he can explain them in what we all admit to be the deepest sense. But the facts do not ask leave either of science or metaphysics to be until the explanations they are looking for have been found. And when we know the facts, I repeat, we know the answers to all these questions that Professor Ladd seems to think that Professor James is under peculiar obligations to answer.
The same line of thought furnishes the reply to another of Professor
