Rocks Quotes - page 9
The second factor, equally important, is that of good continuation and good shape. The things which we see have a better shape, are bounded by better contours, than the holes which we might see but do not. Therefore, when in exceptional circumstances these conditions are reversed, we see the hole and not the things, as the shape of a gap between two projecting rocks with sharp profiles, which may look like a face, an animal, or some other object, while the shape of the rock disappears.
Kurt Koffka
In science there are uses many classifications of entities - plants, animals, rocks, soils, stars, diseases, occupations, and so on. In these taxonomies a classification must display genetic relations - for example, an evolutionary family tree of animal species - but its prime purpose is to aid in the identification of entities... Classification enables us to select, from the whole universe of known entities, the one that best matches one newly encountered.
Brian Campbell Vickery