which we may come to discover to be unreal in exactly the same sense as thoughts may be unreal; i.e. they may not fit in with the rest of our experience and with the experience of sane and healthy persons. The antithesis between sensations (in the psychological sense) and thoughts cannot be an absolute one. If by sensation be meant, not simply the excitation of a nerve (which may not be felt and so is not psychologically a sensation), but a sensation as felt, and, moreover, felt as this or that sensation, i.e. discriminated, here we already have an act of judgment (Aristotle defines αἴσθησις as δύναμις κριτική); and it is this judgment which we pronounce to be true or false according as it corresponds or not to reality (i.e. the rest of our experience and the experience of other people). A person hypnotized may be made to feel a sensation of heat, when there is no cause external to his organism to produce the sensation, and not to feel the prick of a pin where there is an external cause. In such cases the sensation, or absence of sensation, not being such as persons in a normal condition would experience, is not considered to correspond to reality.
I fancy that to some persons a sensation might seem to have more reality than a thought, because the organism is affected in an obvious way in the case of sensation, either by some external or internal stimulus, whereas a thought does not so obviously depend on any organic process, and was in old-fashioned psychological theories supposed to occur independently of anything happening in the brain. But all scientific psychologists would, I imagine, admit now that thoughts must have their physiological equivalents just as much as sensations, although in the former case what happens in the brain is much more complex, obscure, and difficult to discover.
Pleasure and pain seem to have reality in a special degree: pain in particular forces itself on our consciousness, in a way which may make mere thoughts or ideas seem unreal in comparison. But pleasure and pain are purely subjective feelings. As psychical events they have no more reality than thoughts as psychical events. When people try to argue one out of a feeling of pleasure or of pain, they do so by saying that it is not
