245. If the first sentence of the above had been found by Hume in an author whom he was criticising, he would scarcely have been slow to pronounce it tautological. As it stands, it simply tells us that having seen things extended we consider their extension, and upon considering it acquire an idea of it. It is a fair sample enough of those ‘natural histories’ of the soul in vogue among us, which by the help of a varied nomenclature seem able to explain a supposed later state of consciousness as the result of a supposed earlier one, because the terms in which the earlier is described in effect assume the later. It may be said, however, that it is only by a misinterpretation of a carelessly written sentence that Hume can be represented as deriving the idea of extension from the consideration of distance; that, as the sequel shows, he regarded the ‘consideration’ and the ‘idea’ in question as equivalent, and derived from the same impression of sense. It is undoubtedly upon his account of this impression that his doctrine of extension depends. It is described as ‘an impression of coloured points disposed in a certain manner.’ To it the idea of extension is related simply as a copy; which, we have seen, properly means with Hume, as a feeling in a less lively stage is related to the same feeling in a more lively stage. It is itself, we must note, the _impression_ of extension; and it is an impression of sense, about which, accordingly, no further question can properly be raised. Hume, indeed, allows himself to speak as if it were included in a ‘perception of visible bodies’ other than itself; just as in the passage from the fourth book previously examined, he speaks as if the perception, called extension, were a quality of some other perception. This we must regard as an exercise of the privilege which he claims of ‘speaking with the vulgar while he thought with the learned;’ since, according to him, ‘visible body,’ in any other sense than that of the impression of coloured points, is properly a name for a ‘propensity to feign’ resulting from a process posterior to all impressions of sense. The question remains whether, in speaking of an impression as one of ‘coloured points disposed in a certain manner,’ he is not introducing a ‘fiction of thought’ into the impression just as much as in calling it a ‘perception of body.’ The points must be themselves impressions, and therefore not co-existent.