[1254a] Now the tools mentioned are instruments of production, whereas an article of property is an instrument of actioni.e. with it we do not make something but do something (e.g. wear a dress, lie in a bed).; for from a shuttle we get something else beside the mere use of the shuttle, but from a garment or a bed we get only their use. [loeb_subsection_6] And also inasmuch as there is a difference in kind between production and action, and both need tools, it follows that those tools also must possess the same difference. But life is doing things, not making things; hence the slave is an assistant in the class of instruments of action.
And the term article of property is used in the same way as the term part: a thing that is a part is not only a part of another thing but absolutely belongs to another thing, and so also does an article of property. Hence whereas the master is merely the slave’s master and does not belong to the slave, the slave is not merely the slave of the master but wholly belongs to the master.
[loeb_subsection_7] These considerations therefore make clear the nature of the slave and his essential quality: one who is a human being belonging by nature not to himself but to another is by nature a slave, and a person is a human being belonging to another if being a man he is an article of property, and an article of property is an instrument for action separable from its owner. But we must next consider whether or not anyone exists who is by nature of this character, and whether it is advantageous and just for anyone to be a slave, or whether on the contrary all slavery is against nature. [loeb_subsection_8] And it is not difficult either to discern the answer by theory or to learn it empirically. Authority and subordination are conditions not only inevitable but also expedient; in some cases things are marked out from the moment of birth to rule or to be ruled. And there are many varieties both of rulers and of subjects (and the higher the type of the subjects, the loftier is the nature of the authority exercised over them, for example to control a human being is a higher thing than to tame a wild beast; for the higher the type of the parties to the performance of a function, the higher is the function, and when one party rules and another is ruled, there is a function performed between them)—[loeb_subsection_9] because in every composite thing, where a plurality of parts, whether continuous or discrete, is combined to make a single common whole, there is always found a ruling and a subject factor, and this characteristic of living things is present in them as an outcome of the whole of nature, since even in things that do not partake of life there is a ruling principle, as in the case of a musical scale.Each mode (Dorian, the modern minor scale, Phrygian and Lydian, two forms of major) was ruled by its key-note. However, this matter perhaps belongs to an investigation lying somewhat outside our subject. [loeb_subsection_10] But in the first place an animal consists of soul and body, of which the former is by nature the ruling and the latter the subject factor. And to discover what is natural we must study it preferably in things that are in a natural state, and not in specimens that are degenerate. Hence in studying man we must consider a man that is in the best possible condition in regard to both body and soul, and in him the principle stated will clearly appear,—
[1254b] since in those that are bad or in a bad condition it might be thought that the body often rules the soul because of its vicious and unnatural condition. [loeb_subsection_11] But to resume—it is in a living creature, as we say, that it is first possible to discern the rule both of master and of statesman the soul rules the body with the sway of a master, the intelligence rules the appetites with that of a statesman or a king and in these examples it is manifest that it is natural and expedient for the body to be governed by the soul and for the emotional part to be governed by the intellect, the part possessing reason, whereas for the two parties to be on an equal footing or in the contrary positions is harmful in all cases. [loeb_subsection_12] Again, the same holds good between man and the other animals: tame animals are superior in their nature to wild animals, yet for all the former it is advantageous to be ruled by man, since this gives them security. Again, as between the sexes, the male is by nature superior and the female inferior, the male ruler and the female subject. And the same must also necessarily apply in the case of mankind as a whole; [loeb_subsection_13] therefore all men that differ as widely as the soul does from the body and the human being from the lower animal （and this is the condition of those whose function is the use of the body and from whom this is the best that is forthcoming） these are by nature slaves, for whom to be governed by this kind of authority is advantageous, inasmuch as it is advantageous to the subject things already mentioned. For he is by nature a slave who is capable of belonging to another （and that is why he does so belong）, and who participates in reason so far as to apprehend it but not to possess it; for the animals other than man are subservient not to reason, by apprehending it, but to feelings. [loeb_subsection_14] And also the usefulness of slaves diverges little from that of animals; bodily service for the necessities of life is forthcoming from both, from slaves and from domestic animals alike. The intention of nature therefore is to make the bodies also of freemen and of slaves different—the latter strong for necessary service, the former erect and unserviceable for such occupations, but serviceable for a life of citizenship （and that again divides into the employments of war and those of peace）; but as a matter of fact often the very opposite comes about—some persons have the bodies of free men and others the souls; [loeb_subsection_15] since this is certainly clear, that if persons were born as distinguished only in body as are the statues of the gods, everyone would say that those who were inferior deserved to be these men’s slaves. And if this is true in the case of the body, there is far juster reason for this rule being laid down in the case of the soul; but beauty of soul is not so easy to see as beauty of body.