For such judgments are not a simpler and more direct way of taking cognisance of things, but a more indirect and more complex way. It is not thereby shown to be a less primitive process. On the contrary, simplified ways of thinking are commonly advanced products. The ‘intuitive’ person uses his cœnesthesia as a chemist uses his reagents or a physiologist his galvanometer. As far as the sensations which the colour stimuli excite can be optically discriminated, no difference is perceptible. But an actual yet sensorily imperceptible difference becomes apparent through the difference in organic reaction. The process is merely one of adding further and more delicate signs to the situation, it is analogous to attaching a recording lever to a barograph. The differences between sensitive or ‘intuitive’ and more ‘rational’ and obtuse individuals may be of two kinds. It may be that the sensitive person’s organic response is more delicate. This is a difficult matter to decide. It is certain, however, that the chief difference (a derivative difference very likely) lies in the fact that the obtuse person has not learned to _interpret_ the changes in his general bodily consciousness in any systematic fashion. The changes may occur and occur systematically, but they mean nothing definite to him. This kind of intervention of organic sensation in perception plays a part in all the arts. Much neglected, it is probably of very great importance. What here needs to be noticed is that it is not a mode of gaining knowledge which differs in any essential way from other modes. No unique and peculiar relation of ‘feeling’ towards things needs to be introduced to explain it, any more than a unique and peculiar mode of ‘cognitively apprehending’ them needs to be introduced to explain ordinary knowing. In both instances their causes, which have to be assumed in any case, will suffice. When we sense something our sensation is caused by what we sense. When we refer to something absent, a present sensation similar to sensations which in the past have been coincident with it, is thereby a sign for it, and so on, through more and more intricate mnemic sign-situations. Here a present colour sensation gives rise to an organic response which has in the past accompanied a definite colour; the response becomes then a sign of that colour which the sensitive and discriminating person trusts, although he is optically unable to make sure whether that colour is present or merely one very like it. Other cases differ from this in complexity but not in principle. If it is objected that this account of referring or thinking in terms of causes gives us at best but a very indirect way of knowing, the reply is that the prevalence of error is itself a strong argument against a too direct theory of knowledge.