This narrowing and consequent deepening, which has led to all our sense-impressions being adapted to and ordered with those of sight, has led also to the replacement of the innumerable methods of thought-communication known to animals by the one single medium of language, which is a bridge _in the light-world_ between two persons present to one another’s bodily or imaginative eyes. The other modes of speaking of which vestiges remain at all have long been absorbed into language in the form of mimicry, gesture, or emphasis. The difference between purely human speech and general animal utterance is that words and word-linkages constitute a domain of inward light-ideas, which has been built up under the sovereignty of the eyes. Every word-meaning has a light-value, even in the case of words like “melody,” “taste,” “cold,” or of perfectly abstract designations. Even among the higher animals, the habit of reciprocal understanding by means of a sense-link has brought about a marked difference between _mere_ sensation and _understanding_ sensation. If we distinguish in this wise _sense-impressions_ and _sense-judgments_ (e.g., scent-judgment, taste-judgment, or aural-judgment), we find that very often, even in ants and bees, let alone birds of prey, horses, and dogs, the centre of gravity has palpably shifted towards the judgment side of waking-being. But it is only under the influence of language that there is set up within the waking-consciousness a definite _opposition_ between sensation and understanding, a tension that in animals is quite unthinkable and even in man can hardly have been at first anything more than a rarely actualized possibility. The development of language, then, brought along with it a determination of fundamental significance--_the emancipation of understanding from sensation_.