commonplace realism about simple things to be realism when applied to very complex things. It seems at first glance more realistic to suppose that sourness is inherent in vinegar than that it is always a sensation in some percipient. But that the former hypothesis is very unrealistic is easily seen when we put such crude metaphysics in other words; the doctrine then is that part of the taster's own mind is outside himself. It is possible for the same person to be truly realistic in simple things, and to be intensely unrealistic in complex things. Thus, the really practical man, who may tell us that he despises metaphysics, may be crudely metaphysical when he deals with complex things—"explaining," for example, that a man comatose does not move because he has lost consciousness. Surely the truly realistic conception is that the comatose patient does not move any of his limbs from some physical disability—for essentially the same reason that a hemiplegic man does not move his arm and log.
I now go back to my small joke chat punning is a slightly morbid mental state, a "mental diplopia," a caricature of the normal "diplopia" of healthy mentation. From this point I make the assertion that the "physiological insanity" of dreaming is diplopic—a caricature of that of waking mentation. A physician reads in the day of the strained relations of European states; in his dream at night he is called in consultation by Bismarck, and advises a course of the iodide of potassium (directions for the application of the remedy were not given). Clearly, there are here two very dissimilar mental states "pretending" to be stereoscopic; manifestly a seeming fusion of ideas of prescribing for a patient with ideas of the attitude of European states. I hope some time to be able to show that such diplopia has the same kind of mechanism as that of the pun—that the two elaborate dissimilar states are held together by two same, or similar, simple mental states. I go on to remark that in some people there are beliefs as incongruously diplopic as some states in dreams—diplopic in that way to other people, at any rate:—(1). Killing a rabid dog to prevent people already bitten by it going mad. (2). Imagining it to be possible to study what are called "diseases of the mind" methodically without distinguishing between the physical and the psychical. (3). A cleanly mother, from maternal solicitude, refraining from washing the top of her baby's head, lest it should come to have "water on the brain." (4). Imagining it to be possible to investigate complex subjects without the use of hypotheses; for instance, that Harvey could have made observations and experiments to prove the circulation of the blood without supposing beforehand that it did circulate, (.5). Anointing a blade with healing salve to cure a wound inflicted by the blade.
Once more I go back to punning for a new start, trying to show again by very simple cases that punning is only a caricature of, and therefore for the psychologist a valuable experiment on, the process of normal mentation. I take first a case which is almost if not quite a