THE NATURE OF THE TANGIBLE
tHE next proposition I shall try to establish about immediate tactual perception is that, with the exception of heat and cold, all the tangible qualities reduce to spatial properties of objects.
Size, shape and motion are themselves spatial properties, and so require no discussion. A rough surface is a surface of an object in the solid state, a surface that has some degree of hardness, and a certain irregular shape. It is this hard irregularity which ensures that such a surface will not move easily over the skin. A smooth surface differs only in lacking irregularity of shape. So roughness and smoothness can be analysed in terms of the spatial properties of surfaces, together with the properties of hardness, and being in the solid state.
A hard object is one that does not change its shape, or break up easily (a form of change of shape), under pressure; while a soft object does change its shape easily under such conditions. So hardness and softness are analysable in terms of shape and pressure. Liquids and solids are distinguished by the different contours that something liquid and something solid assume in various circumstances. (It is a mark of a liquid that it
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Publication information: Book title: Bodily Sensations. Contributors: D. M. Armstrong - Author. Publisher: Routledge & Paul. Place of publication: London. Publication year: 1962. Page number: 21.