Such theories are clearly an exaggeration of the fact that the localization of our bodily sensations during sleep is necessarily imperfect.[90] In many cases the image called up bears on its objective side no discoverable resemblance to that of the bodily region or the exciting cause of the sensation.

Here the explanation must be looked for in the subjective side of the sensation and mental image, that is to say, in their emotional quality, as pleasurable or painful, distressing, quieting, etc.

It is to be observed, indeed, that in natural sleep, as in the condition known as hypnotism, while differences of specific quality in the sense-impressions are lost, the broad difference of the pleasurable and the painful is never lost.

It is, in fact, the subjective emotional side of the sensation that uniformly forces itself into consciousness.

This being so, it follows that, speaking generally, the sensations of sleep, both external and internal, or organic, will be interpreted by what G.H.Lewes has called "an analogy of feeling;" that is to say, by means of a mental image having some kindred emotional character or colouring.
Now, the analogy between the higher emotional and the bodily states is a very close one.