καὶ ἶσοι : Aristotle on diversity and equality in the constitution of polis ἕτεροι καὶ ἶσοι

In this paper, we focus on difference as a feature of political community, in Greek Ancient thought. There usually describes the Greek conception of polis as a community of equals. This is a very important legacy. However, this is not the same as to (misleadingly) state it as a homogeneous community (as Émile Durkhein does in De la division du travail social, 1893). The tension between equality and diversity is a paramount political theme, and there is a lot to learn about this from Aristotle. His investigations on the nature of polis propose an original combination of equality and difference to ground human associations. 1 Doutor em Direito (UGF). Professor (UERJ). 2 Professor Adjunto do Departamento de Teoria e Fundamentos do Direito da Faculdade de Direito da UERJ; Diretor Adjunto da Faculdade de ireito de Valença FAA/FDV. Coordenador de Pesquisa e Iniciação Científica (20082012) da Faculdade de Direito do Centro de Ensino Superior de Valença. Professor Titular da Universidade Estácio de Sá e UNIPAC-JF. Professor Adjunto da Unisuam. ἕτεροι καὶ ἶσοι: ARISTOTLE ON DIVERSITY AND EQUALITY... Revista Brasileira de Estudos Políticos | Belo Horizonte | n. 114 | pp. 79-103 | jan./jun. 2017 80 This is my point: how can we say that polis is, at the same time, an association of equal but different people? This is relevant for understanding justice as a central feature and task of political life. Although there is a lot elsewhere to consider, we explore this question from some selected arguments presented in Aristotle’s Nicomachean Ethics (Book V), and Politics (Books I and II). Methodically, we try to understand every statement from its dialectical context of inquiry. This makes Topics a relevant background (or even a guide) to the approach we propose.

This is my point: how can we say that polis is, at the same time, an association of equal but different people?This is relevant for understanding justice as a central feature and task of political life.Although there is a lot elsewhere to consider, we explore this question from some selected arguments presented in Aristotle's Nicomachean Ethics (Book V), and Politics (Books I and II).Methodically, we try to understand every statement from its dialectical context of inquiry.This makes Topics a relevant background (or even a guide) to the approach we propose.Keywords: Aristotle; Diversity; Equality; Justice; Politics.

METHODIC REMARKS 3
Dialectic is the method Aristotle uses in most of his practical treatises, we assume.As he states in Topics, there are three uses for Dialectic, all of them strictly interconnected.It is useful as exercise for disputes and discussions, for conversations, and for philosophical sciences (Top.I, 2, 101 a 26-28).Politics and Ethics are examples of its philosophical use. 4 3 We have investigated different aspects of the subject in recent papers: "Politics and equality in Greek invention of democracy", and "Controversy and practical reason in Aristotle".The first version of this paper was delivered to Special Workshop "Aristotle and the Philosophy of Law: Justice and Society", in the 26th World Congress of Philosophy of Law and Social Philosophy of the International Association for Philosophy of Law and Social Philosophy (Internationale Vereinigung für Rechts-und Sozialphilosophie -IVR).
4 "For the study of the philosophical sciences it [Dialectic] is useful, because the ability to raise searching difficulties on both sides of a subject will make us detect more easily the truth and error about the several points that arise.It has a further use in relation to the ultimate bases of the principles used in the several sciences.For it is impossible to discuss them at all from the principles proper to the particular science in hand, seeing that the principles are the prius of everything else: it is through the opinions generally held on the particular points that these have to be discussed, and this task belongs properly, or most appropriately, to dialectic: for dialectic is a process of criticism wherein lies the path to the principles of all inquiries."(Top.I, 2, 101 a 34-36).There is a huge discussion about the use of Dialectic in Aristotle's different works.Scholars dispute about its meaning, and different views on Dialectic lead to varying positions about its employment.About this, The reader must be aware of it, or the texts may look a bit confusing and contradictory.Many times it is difficult to discern Aristotle's own opinion among the multitude of voices he brings to discuss both sides of every theme.
Dialectic is a method to deal with controversy and dispute.Differently from scientific knowledge (episteme), the dialectical researcher does not have evident and necessary axiomata from which deduce conclusions.He must deal with contending reliable opinions (endoxa), and it is not clear, from the beginning, which ones of them are true -or even if any of them is true; dialectic is exactly the method to discern it, as far as possible.
In its primary use, dialectic is a technic to win face-to-face debates.These ones have a question-answer structure, and their goal is leading the opponent, through sequential questions, to accept the thesis adopted by the inquirer.This arrangement makes scientific and dialectical syllogisms quite different.Scientific syllogism is a display (ἀπόδειξις) of conclusions which follow grounding (ἀλήτων) principles (πρώτωι), "for in regard to the first principles of science it is improper to ask any further for the why and wherefore of them" (Top.I, 1, b 21-22).Scientist just has to state the premises, to ground the conclusion.For example: Men are mortal.Socrates is a man.Then, Socrates is mortal.The dialectician, instead, deduces from premises see Frede (2012), Salmierwe (2009) and Cooper (2009).We assume the term "Dialectic" in a very broad sense, as to mean all inquiring which starts from endoxa (opinions which are not evident but reliable, reputed but disputable) and which tries to understand something from exploring all kinds of problema and aporia (the contradicting opinions and arguments) which rises from them.we do not need to accept any compromise of Dialectic to the truth of common sense (as Aristotle does not use endoxa in order to just endorse them, indeed), and neither need to oppose Dialectic and Definition as two exclusionary ways of investigation (as defining is indeed a central procedure in dialectical efforts).that are not undeniable.In order to progressing with his "demonstration", he must obtain the acceptance of the answerer first.Questioner's conclusion can only be produced after his premises obtain accordance.Hence, his premises are questions.As an example: Is life according to excellence good?(Yes.)Is ethical virtue an excellence?(Yes.)Then, life according to ethical virtue is good.
The dialectician learns to collect his premises from reputed opinions (endoxa), as this may increase their acceptance. 5cceptance, however, may fail.When the answerer rejects the premise, it turns into a problem. 6If the question "is this X?" receives the answer "no", this causes the rise of a problem: "is this X, or not?" 7 Aporia is the difficulty the answerer puts to resist to interrogator's argument.Before a problem (the answerer's "no!"), the interrogator has to suspend his progress, until solving the difficulty.As the art of dialectic consists in overcoming this sort of difficulties, 5 "A dialectical premiss is the asking of something acceptable to everyone, most people, or the wise (that is, either all of them, most of them, or the most famous), provided it is not contrary to opinion (for anyone would concede what the wise think, so long as it is not contrary to the opinions of the many)."(Top, I, 10, 104 a).
6 "A dialectical problem is a point of speculation, directed either to choice and avoidance or to truth and knowledge (either on its own or as working in conjunction with something else of this sort), about which people either have no opinion, or the public think the opposite of the wise, or the wise think the opposite of the public, or each of these groups has opposed opinions within itself."(Top.I, 11, 104 b).
7 "A problem is different from a premiss in its form.For stated in this way: 'Is it the case that two-footed terrestrial animal is the definition of man?' or, 'Is it the case that animal is the genus of man?' it is a premiss; but stated in this way: 'Whether two-footed terrestrial animal is the definition of man or not', it becomes a problem (and similarly in other cases).Consequently, it stands to reason that problems and premisses are equal in number, since you may make a problem out of any premiss by changing its form."(Top.I, 4, 101 b).
we may say that problems are the starting point of every dialectical inquirer.
The technic to solve aporiai basically involves the usage of common places (topoi).These are arguments with high probability to be accepted by any discusser, thus useful to decide between the alternatives opened by problems.
The philosophical use Aristotle himself makes of dialectic in Politics reveals the adapted employment of endoxa as dialectical premises, their conversion into problems, and the use of topoi as tools to decide among conflicting possibilities.
Of course there is no question-answer structure, as Aristotle didn't write dialogues but treatises.But he systematically brings to discussion reputed opinions to start investigation.Endoxa are brought to face other ones, and the thesis of Aristotle himself.He crosses these aporiai using topoi he describes in Topics, and all this helps him to take stand on the matter.
Next we recall some arguments from EN V and Politics I and II about the nature of polis, considering them as parts of dialectical investigations.It means trying to understand them as efforts at solving problems, in the context of struggling opinions, with the aid of topoi.
The Books we selected start from sound statements about the method.Aristotle plainly wants us to be warned about their dialectical arrangement.Let us see what happens.

DEVELOPMENT Defining the political
A major task of Politics is to understand polis and the political. 8aving knowledge of something is being able to define it.Aristotle clarifies polis by distinguishing it from other kinds of association or community (κοινωνία).
All associations seek a certain good: this is a feature of the genus "κοινωνία" 9 , which must mark every species which belongs to it. 10The different kinds of κοινωνία differ accordingly to the kinds of good they seek.The hierarchy among the ends of the associations establishes the hierarchy among the associations themselves: the end of polis is the most supreme (κυριωτάτη), thus polis is the most supreme association. 11This is the first (although brief) move to differentiate polis from the other types of human association.12 9 The teleological emphasis of Politics recalls once again the beginning of Ethics.Both open investigations by stating that the end is capital do understand the genus within which the subject of study will be framed: action among (always teleological) human activities, in Nicomachean Ethics; political association among (always teleological) human associations, in Politics.
10 "(…) for of all the elements of the definition the genus is usually supposed to be the principal mark of the essence of what is defined" (Top.VI, 1, 139 a 29-31).
11 The argument reminds some topoi presented at Top. III, 1: "In general, too, a means directed towards the end of life is more desirable than a means to anything else (…) of two productive agents that one is more desirable whose end is better (…) For what produces happiness exceeds what produces health just as much as happiness exceeds health." Aristotle dialectically organizes the subject from the problematization of the reputed opinion (ἔνδοξος) according to which political, royal, despotic and familiar ruling (πολιτικός, βασιλικός, δεσποτικός and οἰκονομικός) are "the same". 13The choice of the platonic opinion for the beginning of the inquiry is not casual.Besides being hold by an esteemed philosopher, it allows Aristotle to explore essential aspects of political community.The demonstration of the peculiarity of the political occupies most of his argumentation in Politics.
The opinion questioned identifies political community to other forms of community.The problem is to know if πολιτικός, βασιλικός, δεσποτικός and οἰκονομικός are the same (εἶναι τὸν αὐτὸν), or if they differ (διαφέρειν) (Pol.1.1252a 5-10). 14ristotle stands firmly against the identification: Those then who think that the natures of the statesman, the royal ruler, the head of an estate and the master of a family are the same, are mistaken.(Pol.1.1252a) According to Top., I, 7, an important part of dialectician's work is to distinguish the meaning of "the same", which can be said in three different ways: in number (the same thing), before.The means whereby we are to become well supplied with reasonings are four: (1) the securing of propositions; (2) the power to distinguish in how many senses particular expression is used; (3) the discovery of the differences of things; (4) the investigation of likeness."(Top.105 a 20-25.) 13 The opinion under attack is platonic.The same problem is proposed at Stateman, 258e: "Shall we then assume that the statesman, king, master, and householder too, for that matter, are all one, to be grouped under one title, or shall we say that there are as many arts as names?"Plato concludes they are the same as they hold the same knowledge.It is interesting to observe that this topos, according to which something is the same as far as falls under a same science, is employed by Aristotle in Politics I as well.
14 Top.I, 5, 102a 7-9 : "in connection with definitions, the better part of our time is taken up with whether things are the same or different."First of all, we must determine the number of ways that 'same' is used.We may regard the same as being divided, in outline, into three parts, for we are accustomed to describe what is the same as 'in number' or 'in species' or 'in genus'.(Top., I, 7) 16 In which sense can be πολιτικός, βασιλικός, δεσποτικός and οἰκονομικός said as the same?According to Plato, they seem to belong to the same species (or even to be the same person).Aristotle disagrees: he thinks they are identical only in genus, but are different in kind.
Plato fails because he thinks that the difference between the political and the other types of κοινωνία is not essential, but merely of number of the people who obey or rule.
(…) they [the Academics] imagine that the difference between these various forms of authority is one of greater and smaller numbers, not a difference in kind.(Pol.1.1252a) Hence, Aristotle puts the genus-component at the dialectical stage: κοινωνία."Since a definition is composed of a genus and differentiae" (Top.I, 8, 103 b), he must next uncover the peculiar features of the political, to discern its specificity.

General strategy to find the eídos of polis
Aristotle faces the task of finding the specificity of polis among the different kinds of human communities "in accordance with our [his] regular method of investigation".That means "to analyze the composite whole down to its uncompounded elements (for these are the smallest parts of the whole)" (Pol.I, 1. 2-5).This analytic method guides him to find the essential difference he seeks.He studies the human associations from the simple (not composite: ἀσύνθετος) elements they come from.This method implies understand things as they develop (φύω, verb from which φύσις -nature -originates) from the beginning (or "from the principle": ἐξ ἀρχῆς).That means: the way they are by nature (φύσει).
His twofold strategy involves understanding the constitutive elements of the community, and the "development process from the principle" (nature) which is responsible for being polis the way it is.The two paths are the same, because the principle from which associations develop rests on the simple (decompounded) parts.

Communities germinate from human necessities
Understanding how things develop from their principle (that means, by nature) requires investigating the inner necessity which pushes things to be what they are.The various types of association arise from different types of necessity.This is central in Aristotle's differentiation of polis.
Household answers to daily needs.Villages aim at more than simply surviving, but at ease.Poleis aim at more than comfortable life: they seek the good life (εὐδαιμονία).In this sense, polis is the specifically human association, and thus the human being is, by nature, a political animal (ὁ ἄνθρωπος φύσει πολιτικὸν ζῷον).
The principle from which (ἐξ ἀρχῆς) any association develops (φύω) is human needy condition.Anyone partakes any association as far as foresees some good for himself -i.e., because membership answers to some desire.It is one and the same investigation: about nature of association/community, about the necessity which pushes one to associate, and about the good aimed by its members.
It is necessary to discover the principle (the human need and thus the anticipated good which inflames desire) to which each association responds, in order to discover its essence and to distinguish its species.Self-sufficing (αὐτάρκεια) is the general goal of every association (as each one is not self-sufficient if he keeps apart: εἰ γὰρ μὴ αὐτάρκης ἕκαστος χωρισθείς). 17 Necessity (ἀνάγκη) of descendants is the principle that pushes male and female to the most basic form of association.There is nothing specifically human in this: the same impulse 17 In the investigation on the "development from the beginning" (nature), the ἀρχῆ is the end (τέλος).Aristotle's inquiry about nature is quite different from Moderns: we are especially concerned about causes, while Aristotle talks about ends.It is no absurd to think about necessity as the principle from which associations arise.All associations aim at some good and thus to the satisfaction of some human necessity, to the fulfillment of same lack: of a need.Accepting necessity as the principle from which the associations arise is as the same as stating that associations aim at some good.
is found even in plants.It is not anything we can choose (οὐκ ἐκ προαιρέσεως), for we are thrown (ἐφίεσθαι) to this by nature (φυσικὸν).Necessity (the need of security) also grounds the natural union between the "natural ruler" (the "natural master": δεσπόζω φύσει) and the "natural subject" (the "natural slave").
Regarding to its specific end, polis differs for it aims at the complete human satisfaction.Poleis come into existence not just for the sake of life, but for the good life (εὖ ζῆν).Partaking in the polis is the source (γενέσεως) of human accomplishment (τελεσθείσης).This way, Aristotle elucidates how polis develops according to its principle: it answers to the need (δεόμενος) of αὐτάρκεια.
Being self-sufficient and independent (αὐτάρκης) is the end of human being, but he needs to associate to accomplish it.Necessity marks humanity.Neither the beast (which does not desire it) nor the god (who is αὐτάρκης already) has the human nature.
In polis, participate those (human beings) who need (δέω) it to reach αὐτάρκεια.Each one apart (ἕκαστος χωρισθείς) does not suffice, and this way nature pushes us to political community.From this principle, there develops (φύσει) the impulse (ὁρμὴ) to political association.

All communities are hierarchical
There is a natural difference among the participants in the basic (familiar) forms of κοινωνία, which is decisive to their formation.Difference makes association useful for male and female, master and slave, father and children. 18 The different kinds of community aim at the benefit of all associates.
Aristotle must sustain it, or the association would lose its teleological feature: to aim at the good of the participants.To keep this valid, Aristotle develops It introduces hierarchy as an essential feature of every association.Every association is a sort of domination.
In every composite being, there is a part that rules, and another that obeys. 19That also happens to human as a bodysoul composite, each part destined by nature to rule (mind) or to be ruled (body).The same is right for human associations, within which one part naturally tends to command, other ones to obey: male over female and children, master over slaves.Associations ground on inequality, and in spite of this (or just because of this, we should say) it is better (βελτίων) and profitable (συμφέρει) for everybody to keep associated.
Thus, hierarchy integrates the explication about how associations are brought into existence according to their principle (by nature).
These arguments sound disgusting to contemporary readers.But that (the natural supremacy of some over others) is not the thesis Aristotle wants to demonstrate in Politics I. His point is discovering the specificity of the political; the exposition of associations among non-equal human beings helps exactly to put, at the dialectical stage, the other of the political. 20As it is broadly known, according to Aristotle polis is the association of equal men: "Republican government the arguments about natural slavery.we can't focus on this important dialectical problem.Aristotle recalls opinions to strongly state the artificial (not by nature, but merely conventional, and bias-based) character of slavery.Aristotle admits that this discussion keeps open while he writes ("even among the learned some hold this view, though others hold the other"), but his conclusion is clear: enslavement of "natural slaves" is fair… 19 "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."(Pol.1.1254a) controls men who are by nature free, the master's authority men who are by nature slaves" (Pol.1.1255b). 21t the beginning of this study, we proposed the question: how can polis be, at the same time, an association of equal but different people?
The elements we brought seem to increase the difficulty.We have seen that the difference of the parts of an association generates domination and hierarchy.As domination and hierarchy also marks polis, can it nevertheless be an association of equal man?
The way Aristotle solves this difficulty is part of his effort to differentiate the political from other species of κοινωνία.By nature, there are two differences to distinguish polis: the end it aims at; and the kind of hierarchy it establishes.
Before focusing more accurately on this, we need to add another ingredient to understand polis.

Polis as association of exchange among different people
Politics I carefully describes the fulfillment of material human necessities.It belongs to the strategy of studying polis as emerging from its principle (φύσει).The considerations on property and acquisition of supplies are important to grasp the passage from the household to village, and so to polis.In household goods are produced, shared and consumed by the associated members themselves.Villages come into authority of a master over slaves is not the same as the authority of a magistrate in a republic, nor are all forms of government the same, as some assert."(Pol.1.1255b)   21 It is a dialectical resource often used, to understand human affairs, to study something from its opposite.It is that Aristotle does here, trying to understand the political association from the non-political associations.
existence with the uprising of barter of household supplies.But there isn't money yet, whose outbreak distinguishes political associations.
With money, "came into existence the other form of wealth-getting", trade".Nicomachean Ethics V-5 details polis as a system of trade, and the role of money in it.The goal, there, is differentiating justice from retaliation, and specifying justice as a kind of proportionality.
Difference is remarked as condition to every exchange: For an association for interchange of services is not formed between two physicians, but between a physician and a farmer, and generally between persons who are different, and who may be unequal, though in that case they have to be equalized.(EN, V, 5).
The difference among the members of the exchange community reflects in the price of the goods or services they offer.
It [money] is a measure of all things, and so of their superior or inferior value, that is to say, how many shoes are equivalent to a house or to a given quantity of food.As therefore a builder is to a shoemaker, so must such and such a number of shoes be to a house, [or to a given quantity of food] (EN, V, 5).
As the "measure of all things", money makes exchanging possible, and subsequently it is necessary to the existence of association at this level (polis).Money assures the commensurability between the exchanging goods, and thus the exchange itself.
If there were no exchange there would be no association, and there can be no exchange without equality, and no equality without commensurability.(EN, V, 5).
There is no polis without trade -and no trade is necessary except between different people (who offer and need different things).Money is exactly necessary to turn possible trade as an association among different people.
It works as a sign of necessity.Once again, Aristotle notes that association springs from human defectiveness.It is need (χρεία) that makes people associate (συνέχει).As need is reciprocal (ἀλλήλων), people associate.Necessity keeps everything together (τοῦτο δ᾽ ἐστὶ τῇ μὲν ἀληθείᾳ ἡ χρεία, ἣ πάντα συνέχει) (EN, V, 5, 1133a)  But not need alone does so: both need and diversity produce association.Diversity, non-auto-sufficiency and necessity roots polis (the shoemaker and the builder needs each other exactly because one of them is not able to build houses he needs, and the other, the shoes).

Diversity and polis
Politics II reaffirms the "nature strategy", and problematizes another Platonic opinion (must the citizens own everything in common, including women and children?).Once again, disagreement helps Aristotle to show an essential feature of polis.This turn, he attacks the Academic "ideal of the fullest possible unity of the entire state, which Socrates takes as his fundamental principle" (Pol.II, 1, 1261 a 15-17).
Yet it is clear that if the process of unification advances beyond a certain point, the city will not be a city at all for a state essentially consists of a multitude of persons (πλῆθος γάρ τι τὴν φύσιν ἐστὶν ἡ πόλις), and if its unification is carried beyond a certain point, city will be reduced to family and family to individual.(Pol.II, 1, 1261 a 17-20) Every association grounds on diversity of its members, in progressive intensities.Polis has the higher grade of diversity among associations.He underlines the diversity which marks polis as essential: And not only does a city consist of a multitude of human beings, it consists of human beings differing in kind.(Pol.II, 1, 1261 a 24-25) Polis doesn't develop from the union of similar (οὐ γὰρ γίνεται πόλις ἐξ ὁμοίων), homogeneous people.
Instead of increase it, exaggerated homogeneity may destroy polis.
Yet it is clear that if the process of unification advances beyond a certain point, the city will not be a city at all for a state essentially consists of a multitude of persons, and if its unification is carried beyond a certain point, city will be reduced to family and family to individual, [20] for we should pronounce the family to be a more complete unity than the city, and the single person than the family; so that even if any lawgiver were able to unify the state, he must not do so, for he will destroy it in the process.(Pol.II, 1, 1261 a 24-25) How can we say that polis is, at the same time, an association of equal but different people?(Question 1) Turning back to our question: how can we say that polis is, at the same time, an association of equal but different people?
At this point, we have elements enough to suspect that this is a false problem.
In a kind of sophistical argument22 , the question we proposed uses the same words to signify different things.It suggests that polis is an association of equal and not equal participants.In Aristotelian terms, notwithstanding, it could never be formulated this way.
It is clear the difference between the use of "equal (and unequal)" and "homogeneous (and heterogeneous)".The distinction between equal and unequal generally occurs in contexts where there is hierarchy, when it assesses the relative positions of the parts in a community, to conclude on whether there is superiority or inferiority.These aspects are generally not involved in the use of homogeneous and heterogeneous.Talking about equality and inequality involves comparing parts in a hierarchical structure, asking who rules and who is ruled.
For Aristotle, polis is an association among ἕτεροι (heterogeneous) and ἶσοι (equal) components, and there is no contradiction in this.Citizens are ἕτεροι (or ἀνόμοιοι) (diverse, different) for they are not identical: they have different characters, needs, jobs, competences and perspectives about life -which push them to associate to each other, in their seek for completeness.
But they are ἶσοι (equal) in the sense that there is no one who is able to naturally rule over any one of them.
Human associations differ according to their grades of heterogeneity and equality.Household relations are more homogeneous than polis, but much less egalitarian. 23n any case, every association grounds on diversity.Slaves benefit from association with their master because it redresses their inability to deliberate.Man and woman are incapable of reproducing one without the other... Woman, slaves and children benefit from the full deliberative capacity of the free adult man.23 (…) "a state essentially consists of a multitude of persons, and if its unification is carried beyond a certain point, city will be reduced to family and family to individual, for we should pronounce the family to be a more complete unity than the city, and the single person than the family".(Pol. 2, 1, 1261a).
These natural differences among the participants of household lead to inequality: they assume, therefore, asymmetrical positions in the hierarchy of the familiar community.The fact that they are different makes them unequal.
The facts about the soul lead us to this conclusion.For there is in it by nature that which rules and that which is ruled and we say that they have different virtues, i.e. [the virtue] of the part that has reason and that of the part without reason.It is clear therefore that the same holds true in the case of the others.So that there are by nature many cases of ruler and ruled.For in different ways the free rules the slave, the male the female, the adult man the child.The parts of the soul are present in them all, but present differently.For the slave has not got the deliberative part at all; the female has it, but it is without mastery, and the child has it, but incomplete.(Pol.I, 1260 a 4-14).
Master and slave, or husband and wife, are ἕτεροι (dissimilar) and ἀνισοῖ (unequal).Their natural differences institute the condition of ruler of the male and free participant in the association.
But something diverse happens in Polis, wherein citizens are ἕτεροι (different) but ἶσοι (equal).This leads to our second question, and helps understanding justice as the bound that keeps polis united.

How relevant is it (being ἕτεροι but ἶσοι) to understand justice as a feature and a task of political life? (Question 2)
It is quite simple to keep things in place in household: those who are different (heteroi) are ipso facto unequal (anisoi).In turn polis should conciliate heterogeneity and equalityand the Greeks were aware that this is not a simple task.Both in Ethics and in Politics, Aristotle keeps clear how important but difficult it is.
In both treatises, the exploration of this problem culminates at the statement of justice as the foundation of polis.
In Politics II 1, 1261a, Aristotle faces the difficulty posed by the fact that polis is a hierarchical association, although it is composed by equal components.Of course this problem there not exists in non-political associations: but how can hierarchy works among equal people, as they don't relate each other as superior or inferior?The solution points at the very definition of citizen: Hence reciprocal equality is the preservative of states, as has been said before in the Ethics.For even among the free and equal this principle must necessarily obtain, since all cannot govern at once: they must hold office for a year at a time or by some other arrangement or period (…) (Pol.II, 1261a) (…) and among peoples where it is impossible because all the citizens are equal in their nature, yet at the same time it is only just, whether governing is a good thing or a bad, that all should partake in it, and for equals thus to submit to authority in turn imitates their being originally dissimilar; for some govern and others are governed by turn, as though becoming other persons; and also similarly when they hold office the holders of different offices are different persons.(Pol.II, 1261a-b)   From this, we may conclude that being ἕτεροι but ἶσοι is directly connected to the task of distributive justice, and that this way it remains central to the assurance of polis in its proper sense.
On the other hand, being ἕτεροι but ἶσοι is connected to the task of commutative justice, as we learn from Nicomachean Ethics 1132b: But in the interchange of services justice in the form of reciprocity is the bond that maintains the association.
The point here is to understand the possibility of reciprocity between parts that are dissimilar.This imposes proportionality as a main feature of justice, and signalizes it as the equilibrium to be always sought in every transaction between citizens.
Commutative justice is thus stated as condition of political coexistence, for it is the condition of trade -and trade, as we saw, is an essential aspect of polis: (…) they then are equal, and can form an association together, because equality in this sense can be established in their case farmer A, food C, shoemaker B, shoemaker's product equalized D; whereas if it were impossible for reciprocal proportion to be effected in this way, there could be no association between them.(EN V, 5, 1133b)   The dialectical frame of justice as the sign of the problematic association among people who are ἕτεροι but ἶσοι is also useful to understand this very important account of Nicomachean Ethics: the political nature of justice.
As Aristotle states in EN 1134b, justice "exist[s] between persons whose relations are naturally regulated by law, that is, persons who share equally in ruling and being ruled".Justice between master and slave, husband and wife, or father and children, is only akin to the political justice, but not the same.This is connected to Politics Book I.Both here and there, Aristotle asks for the link between master and slave, father and children, husband and wife, and citizen and citizen.Justice is appropriate to label only the last kind of relationship, as only this is political.In precise terms, we should reserve the term "justice" to the relation between equals, hence in the context of polis, wherein it indicates the task to keep equality in spite of diversity of the associates.
Justice has nothing to do with the relation between different and unequal, but only between different and equal.

AFTERWORD
Dialectic is probably an infinite path of investigation.It looks for clarification from tensioning logoi.Truth appears from the inquire of both sides of a problem24 , which inaugurates a difficulty to face and solve.Through doing this, the point gets clearer and clearer.
Let us bring an Aristotelian statement to tension the conclusion we offered above.
In Politics IV, 1295b, we read that "surely the ideal of the state is to consist as much as possible of persons that are equal and alike, and this similarity is most found in the middle classes" (βούλεται δέ γε ἡ πόλις ἐξ ἴσων εἶναι καὶ ὁμοίων ὅτι μάλιστα, τοῦτο δ᾽ ὑπάρχει μάλιστα τοῖς μέσοις.).
This seems to contradict our conclusions: nor against Plato, but just like Plato, would Aristotle claim, here, for Polis as a homogeneous association and community?
Once again, it is useful to understand the statement from its argumentative context.
Book IV is concerned to understand the best political regime.But Aristotle's perspective is not utopic: "best" means as good as possible.This varies according to the specificities of each polis.One of the most important criteria to assess the quality of a constitution is capacity to guarantee stability to the polis.
In the chapter 11 of Book IV, he talks about the economic condition of the citizens, wondering about which is better: having great differences of wealth, or not?He thinks that being ἕτεροι, at this point, can endanger the polis, because too much poor and too much rich people behavior in such an inappropriate way that they not fit the requirements of a life among equals.
A high degree of economic heterogeneity which turns political equality unlikely.In this sense, he clearly states that being too much ἕτεροι is not compatible to being ἶσοι.
Political equality roots on diversity, but there are limits to (economic) diversity beyond which (political) equality is destroyed.
But this has nothing to do to a conception of Polis as a homogeneous community.It just warns his listener (and this is a nice advice for our times), that the exaggerated imbalance of wealth is not compatible with political coexistence.