Page - 274 - in The Complete Aristotle

necessarily follow. Thus (e.g.) any one who has stated that it is a property of the sun to be ‘the brightest star that moves over the earth’, has used in describing the property an expression of that kind, viz. ‘to move over the earth’, which is evidenced by sensation; and so the sun’s property could not have been correctly rendered: for it will be uncertain, whenever the sun sets, whether it continues to move over the earth, because sensation then fails us. For constructive purposes, on the other hand, see whether he has rendered the property of a kind that is not obvious to sensation, or, if it be sensible, must clearly belong of necessity: for then the property will in this respect have been correctly stated. Thus (e.g.) a man who has stated that it is a property of a surface to be ‘the primary thing that is coloured’, has introduced amongst the rest a sensible quality, ‘to be coloured’, but still a quality such as manifestly always belongs, and so the property of ‘surface’ would in this respect have been correctly rendered. Next, for destructive purposes, see whether he has rendered the definition as a property: for then the property will not have been correctly stated: for the property of a thing ought not to show its essence. Thus (e.g.) a man who has said that it is the property of man to be ‘a walking, biped animal’ has rendered a property of man so as to signify his essence, and so the property of man could not have been correctly rendered. For constructive purposes, on the other hand, see whether the property which he has rendered forms a predicate convertible with its subject, without, however, signifying its essence: for then the property will in this respect have been correctly rendered. Thus (e.g.) he who has stated that it is a property of man to be a ‘naturally civilized animal’ has rendered the property so as to be convertible with its subject, without, however, showing its essence, and so the property of man’ would in this respect have been correctly rendered. Next, for destructive purposes, see whether he has rendered the property without having placed the subject within its essence. For of properties, as also of definitions, the first term to be rendered should be the genus, and then the rest of it should be appended immediately afterwards, and should distinguish its subject from other things. Hence a property which is not stated in this way could not have been correctly rendered. Thus (e.g.) a man who has said that it is a property of a living creature to ‘have a soul’ has not placed ‘living creature’ within its essence, and so the property of a living creature could not have been correctly stated. For constructive purposes, on the other hand, see whether a man first places within its essence the subject whose property he is rendering, and then appends the rest: for then the property will in this respect have been correctly rendered. Thus (e.g.) he who has stated that is a property of man to be an ‘animal capable of receiving knowledge’, has rendered the property after placing the subject within its essence, and so the property of 274