In the third sense, Aristotle is a naturalist about politics because he holds that the state is natural:
The community [koinSnia] formed of numerous villages is the complete city-state [teleios polis]. This has achieved the limit [peras] of pretty well entire self-sufficiency [aatarkeia]: though it came about merely for the sake of survival, once in existence, it is for the sake of the good life. For this reason [dio] every polis is by nature [phasei], if at least the first communities also are. For the polis is itself the natural aim (telos) of those communities, and nature is what it naturally aims at [hS de phusis telos esti]; for what a thing is when its coming-to-be is fully completed, we say that that is its nature, whether it is a man, a horse, or a house. (Pol. 1252b28-36)
In Aristotle’s philosophy the claim that something is phusei (‘‘by nature,’’ ‘‘natural’’) can stand in more than one opposition. The development of an organism, or any similar process, can be natural as opposed to spontaneous (automatoi) or subject to mutilation (pSrosis) (Part. an. 656a7-12, 686b2-5; Gen. an. 767b5). Events can happen naturally; they can also happen by luck ( tuchei) or accidentally (kata sumbe-bSkos), or again spontaneously (Metaphysics 5.30). A different distinction is between events happening naturally and being made to happen, either by skill (technei) applied in ‘‘production’’ (poiSsis) or by deliberate choice (proairesei) applied in ‘‘action’’ (praxis) (Pol. 1254a7; Metaphysics 1069b). Further, an agent’s possession of a character trait can be a result of nature, or of habituation (ethismos) (Eth. Nic. 2.1). Another and more traditional opposition is taken up by Aristotle when he agrees that human behavior and belief can be natural as opposed to conventional (nomoi) (see e. g. Pol. 1253a31). Finally, Aristotle contrasts what is natural (kataphysin) with what is unnatural (para physin) (see e. g. Pol. 3.6; compare Pl., Leg. 890a2-9, and Grg. 483c for a sophistical argument that the polis is unnatural). Which of these oppositions does Aristotle have in mind when he says that the polis is natural?
He cannot mean all of them. Aristotle cannot mean, for instance, that the polis is natural in the way a flower is natural - that it comes about by biological process rather than by human skill and ingenuity. Nor can he mean that the polis is more like an innate character trait than one acquired by habituation, such as a virtue: Aristotle clearly thinks of a good constitution as the equivalent in a city of virtue in an individual, which makes the development of the polls more the work of ‘‘second nature’’ than of nature itself (Eth. Nic. 1103a24-5). On the other hand, Aristotle surely does mean that the polis is not unnatural; and that it is not (pace Callicles) merely conventional; and also that it is not spontaneous.
No doubt; but for an adequate understanding of his claim that the polis is natural, we need to see that claim as moving beyond all these senses of the natural/unnatural opposition. When the claim is first made (at Pol. 1252b28-36), Aristotle presents it as the terminus of a line of reasoning about self-sufficiency - a line of reasoning that is more than a little reminiscent of the one Plato uses to establish the ‘‘city of pigs’’ in Republic 2: ‘‘The polis comes into being... because of the fact that each of us is not self-sufficient, but lacks many things; no other principle [arche] establishes the polis’’ (Resp. 369b5-7). So, first, male and female individuals seek each other out because without each other they ‘‘could not even exist’’ (me dunamenous einai, 1252a27). (Interestingly, Aristotle explicitly says that this seeking-out happens not by conscious purpose, ek proaireseos, but because ‘‘the urge to leave behind another individual like oneself’’ is phusikon, ‘‘part of nature’’ - ‘‘instinctive,’’ as we might also translate it (1252a29).) Then ‘‘the natural master and the natural slave’’ (archon de kai arch-omenon phusei, 1252a31) likewise seek each other out - ‘‘for the sake of security,’’ dia ten soterian (1253a31). Evidently Aristotle thinks that the natural master and the natural slave too could not even exist without each other, the master because he could not do all his own work, the slave because he needs the master’s protection and direction. Once these two partnerships are in place we have the household, oikia, a form of natural partnership that suffices ‘‘for everyday needs,’’ eis pasan hemeran (1252b13). Then, Aristotle goes on, ‘‘the first partnership that is established on account of needs that are not everyday [ chresees heneken me epheimerou] is the village [keme]’’ (1252b17). This brings us up to the stage that the argument has reached in the passage quoted above: it is by the combination of these villages (possibly Aristotle has in mind the relation of its demes to the city of Athens2) that we finally get the city-state itself, pases echousa peras tes autarkeias.
This is only the sketch of an argument. Aristotle wants to motivate each step of the development from individuals to polis by appealing to a need that is not yet met. But he does not tell us what the need is that gets us from household to village, or from village to polis, beyond saying that the former need is ‘‘not everyday,’’ and that the polis is unlike families or villages in being ‘‘for the sake of the good life, not merely of life.’’ As for the two mutual needs that he does tell us about - of the two sexes, and of the master and slave - his account of these is decidedly unconvincing. A man does not seek out a woman (or vice versa) merely for the sake of survival, or because without her he will not exist. A ‘‘natural master’’ who will die unless he finds a slave hardly seems worthy of the name. And Aristotle’s suggestion (1252a35) that the natural slave’s interests are identical with the natural master's seems a transparent piece of ideology.
However, we must not allow these superficial faults to distract us from the argument’s deeper faults. The thought behind the argument is that political association is natural just where it meets some sort of need ( anangke) that is unmet by any smaller unit of political association. Hence, the largest natural unit of political association is the one that meets every human need, and when we reach this we have reached the natural terminus of the process of political development: so the polls is natural because it is self-sufficient. The argument’s key notions of need and self-sufficiency both need to be scrutinized. In the next section I consider them in turn.