Aristotle: The Complete Works. Aristotle

for then also the inflexion of the other opposite will be a property of the inflexion of the other opposite. Thus (e.g.) inasmuch as ‘best’ is a property of ‘the good’, ‘worst’ also will be a property of ‘the evil’.

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7

      Next, look from the point of view of things that are in a like relation, and see, for destructive purposes, if what is in a relation like that of the property rendered fails to be a property of what is in a relation like that of the subject: for then neither will what is in a relation like that of the first be a property of what is in a relation like that of the second. Thus (e.g.) inasmuch as the relation of the builder towards the production of a house is like that of the doctor towards the production of health, and it is not a property of a doctor to produce health, it could not be a property of a builder to produce a house. For constructive purposes, on the other hand, see if what is in a relation like that of the property rendered is a property of what is in a relation like that of the subject: for then also what is in a relation like that of the first will be a property of what is in a relation like that of the second. Thus (e.g.) inasmuch as the relation of a doctor towards the possession of ability to produce health is like that of a trainer towards the possession of ability to produce vigour, and it is a property of a trainer to possess the ability to produce vigour, it would be a property of a doctor to possess the ability to produce health.

      Next look from the point of view of things that are identically related, and see, for destructive purposes, if the predicate that is identically related towards two subjects fails to be a property of the subject which is identically related to it as the subject in question; for then neither will the predicate that is identically related to both subjects be a property of the subject which is identically related to it as the first. If, on the other hand, the predicate which is identically related to two subjects is the property of the subject which is identically related to it as the subject in question, then it will not be a property of that of which it has been stated to be a property. (e.g.) inasmuch as prudence is identically related to both the noble and the base, since it is knowledge of each of them, and it is not a property of prudence to be knowledge of the noble, it could not be a property of prudence to be knowledge of the base. If, on the other hand, it is a property of prudence to be the knowledge of the noble, it could not be a property of it to be the knowledge of the base.] For it is impossible for the same thing to be a property of more than one subject. For constructive purposes, on the other hand, this commonplace rule is of no use: for what is ‘identically related’ is a single predicate in process of comparison with more than one subject.

      Next, for destructive purposes, see if the predicate qualified by the verb ‘to be’ fails to be a property of the subject qualified by the verb ‘to be’: for then neither will the destruction of the one be a property of the other qualified by the verb ‘to be destroyed’, nor will the ‘becoming’the one be a property of the other qualified by the verb ‘to become’. Thus (e.g.) inasmuch as it is not a property of ‘man’ to be an animal, neither could it be a property of becoming a man to become an animal; nor could the destruction of an animal be a property of the destruction of a man. In the same way one should derive arguments also from ‘becoming’ to ‘being’ and ‘being destroyed’, and from ‘being destroyed’ to ‘being’ and to ‘becoming’ exactly as they have just been given from ‘being’ to ‘becoming’ and ‘being destroyed’. For constructive purposes, on the other hand, see if the subject set down as qualified by the verb ‘to be’ has the predicate set down as so qualified, as its property: for then also the subject qualified by the very ‘to become’ will have the predicate qualified by ‘to become’ as its property, and the subject qualified by the verb to be destroyed’ will have as its property the predicate rendered with this qualification. Thus, for example, inasmuch as it is a property of man to be a mortal, it would be a property of becoming a man to become a mortal, and the destruction of a mortal would be a property of the destruction of a man. In the same way one should derive arguments also from ‘becoming’ and ‘being destroyed’ both to ‘being’ and to the conclusions that follow from them, exactly as was directed also for the purpose of destruction.

      Next take a look at the ‘idea’ of the subject stated, and see, for destructive purposes, if the suggested property fails to belong to the ‘idea’ in question, or fails to belong to it in virtue of that character which causes it to bear the description of which the property was rendered: for then what has been stated to be a property will not be a property. Thus (e.g.) inasmuch as ‘being motionless’ does not belong to ‘man-himself’ qua ‘man’, but qua ‘idea’, it could not be a property of ‘man’ to be motionless. For constructive purposes, on the other hand, see if the property in question belongs to the idea, and belongs to it in that respect in virtue of which there is predicated of it that character of which the predicate in question has been stated not to be a property: for then what has been stated not to be a property will be a property. Thus (e.g.) inasmuch as it belongs to ‘living-creature-itself’ to be compounded of soul and body, and further this belongs to it qua ‘living-creature’, it would be a property of ‘living-creature’ to be compounded of soul and body.

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8

      Next look from the point of view of greater and less degrees, and first (a) for destructive purposes, see if what is more-P fails to be a property of what is more-S: for then neither will what is less-P be a property of what is less-S, nor least-P of least-S, nor most-P of most-S, nor P simply of S simply. Thus (e.g.) inasmuch as being more highly coloured is not a property of what is more a body, neither could being less highly coloured be a property of what is less a body, nor being coloured be a property of body at all. For constructive purposes, on the other hand, see if what is more-P is a property of what is more-S: for then also what is less-P will be a property of what is less S, and least-P of least-S, and most-P of most-S, and P simply of S simply. Thus (e.g.) inasmuch as a higher degree of sensation is a property of a higher degree of life, a lower degree of sensation also would be a property of a lower degree of life, and the highest of the highest and the lowest of the lowest degree, and sensation simply of life simply.

      Also you should look at the argument from a simple predication to the same qualified types of predication, and see, for destructive purposes, if P simply fails to be a property of S simply; for then neither will more-P be a property of more-S, nor less-P of less-S, nor most-P of most-S, nor least-P of least-S. Thus (e.g.) inasmuch as ‘virtuous’ is not a property of ‘man’, neither could ‘more virtuous’ be a property of what is ‘more human’. For constructive purposes, on the other hand, see if P simply is a property of S simply: for then more P also will be a property of more-S, and less-P of less-S, and least-P of least-S, and most-P of most-S. Thus (e.g.) a tendency to move upwards by nature is a property of fire, and so also a greater tendency to move upwards by nature would be a property of what is more fiery. In the same way too one should look at all these matters from the point of view of the others as well.

      Secondly (b) for destructive purposes, see if the more likely property fails to be a property of the more likely subject: for then neither will the less likely property be a property of the less likely subject. Thus (e.g.) inasmuch as ‘perceiving’ is more likely to be a property of ‘animal’ than ‘knowing’ of ‘man’, and ‘perceiving’ is not a property of ‘animal’, ‘knowing’ could not be a property of ‘man’. For constructive purposes, on the other hand, see if the less likely property is a property of the less likely subject; for then too the more likely property will be a property of the more likely subject. Thus (e.g.) inasmuch as ‘to be naturally civilized’ is less likely to be a property of man than ‘to live’ of an animal, and it is a property of man to be naturally civilized, it would be a property of animal to live.

      Thirdly (c) for destructive purposes, see if the predicate fails to be a property of that of which it is more likely to be a property: for then neither will it be a property of that of which it is less likely to be a property: while if