Essay - Revisiting Nicomachean Ethics and the Concept of Justice in Aristotle

Introduction [1]

The Nicomachean Ethics, a fundamental work by Aristotle (4th century BCE), investigates the supreme good for humans, identified as eudaimonia – a Greek term that transcends the notion of emotional happiness and refers to a full life. Starting from the premise that all human actions aim at hierarchical ends, Aristotle defines eudaimonia as the ultimate, self-sufficient end, pursued for its own sake and capable of harmonizing other goods (such as wealth, honor, and pleasure) in an integrated existence. This realization is not reduced to fleeting subjective states but requires material conditions (health, resources) and virtues developed throughout one's life.

The work is structured in 10 books, combining a dialectical analysis of the ethical opinions of Aristotle's time with a practical teleological approach: it considers the human being in terms of their telos (purpose), emphasizing that ethics concerns concrete action (eupraxia), not mere speculation. Eudaimonia is defined as the activity of the soul in accordance with virtue, which demands the cultivation of two complementary types of excellence: moral virtues (such as courage, temperance, and justice), acquired by habit (ethos), and intellectual virtues (such as theoretical and practical wisdom), developed through teaching.

Aristotle formulates the famous doctrine of the mean for moral virtues: each one consists of a rational balance between vicious extremes. Courage, for example, is the mean between cowardice (deficiency) and recklessness (excess); temperance is the balance between insensitivity and libertinism. Applying this principle to concrete circumstances requires phronesis (practical wisdom), the ability to discern the appropriate good in each context. Unlike theoretical wisdom (which deals with universal truths), phronesis guides mutable human actions and is indispensable for a virtuous life.

Friendship (philia) is treated as a pillar of the happy life. Aristotle distinguishes three types: by utility (mutual interests), by pleasure (emotional attraction), and by virtue (based on the reciprocal desire for the good). The latter, the highest form, strengthens social cohesion and perpetuates justice. However, the apex of eudaimonia is the contemplative life (bios theoretikos), an intellectual activity that exercises reason in the pursuit of knowledge (philosophy, science). Due to its self-sufficiency and its ability to bring humans closer to the divine, this life surpasses even the political life in excellence.

Despite its foundational influence on Western ethics (particularly virtue ethics), the work is criticized for its elitism: Aristotle's distributive justice excluded slaves, women, and foreigners, and the contemplative life presupposed leisure inaccessible to the majority. Nevertheless, his analysis of justice as a relational virtue and his emphasis on contextual equity remain relevant for contemporary political philosophy and law.

The Nicomachean Ethics proposes a project of happiness anchored in practical rationality and moral excellence, in which justice – in its legal, distributive, and corrective dimensions – acts as the foundation of communal life. By integrating virtuous action (praxis), practical wisdom (phronesis), and contemplation (theoria), Aristotle offers a complex vision of the "good life" that anchors individual ethics in the political structure of the polis.

By revisiting Aristotle's concept of justice, this essay proposes a tension-filled reading, identifying not only its theoretical merits but the internal contradictions that emerge when its principles are confronted with their own applications. We argue that these contradictions, far from invalidating the system, constitute a conceptual laboratory that illuminates perennial questions about the relational nature of justice, the limits of practical rationality, and the dangers of the naturalization of social hierarchies.

1 The Theory of Justice (Book V) [2, 3]

Justice (dikaiosyne) is presented as the supreme virtue, as it regulates social relations and synthesizes all other virtues. Aristotle analyzes it in two dimensions:

General Justice (Legal):The fulfillment of laws aimed at the common good of the polis (city-state). It represents the "complete virtue" as it encompasses all forms of moral excellence in relation to others (1130a).

Particular Justice:It subdivides into:

• Distributive: The allocation of honors, wealth, and offices according to proportional merit (geometrically equal).

• Corrective (or Commutative): The correction of transactions and crimes, aiming for arithmetical equality between the parties.

• Reciprocal (antipeponthos): The basis of economic exchanges, ensuring equivalence of value (money as a common measure).

Justice also presupposes equity (epieikeia) – the ability to adapt universal law to particular circumstances when legal rigidity would be unjust. This notion is linked to phronesis, as it requires contextual discernment.

Aristotle's exploration of justice in the Nicomachean Ethics offers a foundational framework that continues to influence contemporary ethical and legal thought – Aristotle's theory of justice directly influenced thinkers such as Thomas Aquinas, John Rawls (justice as fairness), and contemporary theories of distributive justice.

Next, we will address how Aristotle's ideas align with modern concepts, focusing on relational dynamics, equity, voluntariness, the paradox of the ideal judge, and the controversial defense of slavery.

2 Justice as a Relational Virtue: A Phenomenology of Interdependence

Aristotle positions justice as a virtue that cannot be isolated, requiring the presence of others. In Book V, he emphasizes that justice exists only when there is interaction with others, meaning it is a virtue of alterity. This means that, to be just, the individual must consider their relationship with the community and other members, not only their internal state.

This relational view is supported by various sources. For example, an article from the University of Vermont (n.d.) [4] highlights that Aristotle rejects the Platonic conception of justice as an intrapersonal phenomenon (related only to the individual soul) and defines it as something that involves actions and interpersonal relationships. The Stanford Encyclopedia of Philosophy (2022) [5] reinforces that, for Aristotle, justice is a virtue of character and political arrangements, always involved in social interactions, such as distributing goods or correcting injustices.

2.1 Types of Particular Justice and Their Relational Nature

Aristotle divides justice into universal and particular. Universal justice refers to obedience to laws and conformity with societal norms, while particular justice is more specific and involves the distribution of goods and the correction of imbalances between individuals. Both forms are profoundly relational, as detailed below:

Distributive Justice:This form of particular justice concerns the allocation of goods, honors, or resources among the members of a society. Aristotle argues that distributive justice should follow a geometric proportion, where what each person receives is proportional to their merit or contribution to the community. For example, if A contributes twice as much as B, A should receive twice as much as B. This proportion is not fixed but depends on the context and needs of society. Distributive justice is therefore inherently relational, as it involves comparing the contributions and rights of different individuals, always in relation to one another.

The Stanford Encyclopedia of Philosophy (2022) [5] explains that distributive justice translates into proportionality, as what each person deserves is proportional to their contributions. This is illustrated by Aristotle in examples such as the distribution of flutes to the best musicians, highlighting that distributive justice regulates how goods are shared among members of society, always considering their relationships.

Corrective or Rectificatory Justice: This form of particular justice deals with the correction of imbalances caused by unjust actions between individuals. Aristotle describes it as an arithmetic proportion, where the goal is to restore the initial equality. For example, if C steals X from D, corrective justice requires that X be taken from C and returned to D, restoring the balance. This form of justice is also relational, as it presupposes interaction between at least two parties and the recognition of harm or imbalance affecting both. Both types of particular justice – distributive and corrective – highlight the importance of interpersonal relationships and the community as the context in which justice occurs. Distributive justice regulates how goods are shared among members of society, while corrective justice ensures that relationships between individuals are maintained in a state of balance, always considering the other.

2.2 Justice and Social Structure

For Aristotle, justice is not only an individual virtue but also an essential characteristic of a well-organized society. He argues that political justice is the foundation for social harmony, and that laws and institutions must be designed to promote justice among citizens. In this sense, justice is relational not only between individuals but also between the individual and the state. Aristotle distinguishes between natural justice and legal justice. Natural justice is universal and unchanging, based on the nature of things, while legal justice is conventional and may vary according to the laws of each society. However, both forms of justice are relational, as they depend on how individuals interact with each other and with the institutions that govern society. Alatrsh (2020) [6] emphasizes that Aristotle's notion of justice is grounded in political and social contexts, aligning with modern debates on equity and rights, always in relation to the community.

2.3 Justice as a Mean between Extremes

Although Aristotle defines justice as a virtue that follows the principle of the mean between extremes (as do all virtues), its application in the relational sphere is particularly complex. In the context of justice, the "mean" is not a fixed quantity but a balanced relationship between the parties involved. For example:

In distributive justice, the mean is achieved when goods are distributed proportionally to the merit of each individual, avoiding both excess (giving too much to someone) and deficiency (giving too little). This is elaborated in an article by NumberAnalytics (2025) [7], which explains that distributive justice is a form of geometric proportion, always comparing the relative contributions.

Here a fundamental tension emerges: if distributive justice assumes merit-based criteria, who determines these criteria? Aristotle acknowledges that different communities value different virtues – democrats value freedom, oligarchs value wealth, aristocrats value virtue (EN 1131a). This cultural relativization of distributive justice anticipates contemporary debates on moral pluralism, which MacIntyre (2001) [8] explores in his critique of the modern project of universal moral grounding, showing how different ethical traditions operate with distinct conceptions of human excellence.

In corrective justice, the mean is restored when the initial equality is regained, correcting the excess on one side and the deficiency on the other, as described in the Stanford Encyclopedia of Philosophy (2022) [5], always in relation to the involved parties. This conception of justice as a mean reflects its relational nature, as it requires a continuous evaluation of the relationships between individuals and the overall harmony of society, always considering the impact on social interactions.

2.4 Contemporary Relevance of Relational Justice

Aristotle positions justice as a virtue that only exists in relation to the other, but his analysis goes beyond mere contractual reciprocity. Aristotelian justice presupposes what we can call ontological recognition – the perception that the very moral existence of the subject is constituted by the presence and dignity of the other. This relational dimension surprisingly anticipates modern concepts of intersubjectivity. When Aristotle states that "justice is the only virtue that seems to be the good of the other" (EN 1130a), he is not merely describing an altruistic orientation, but identifying an ontological structure: the just person only realizes themselves as such to the extent that they recognize and constitute the other as a subject of rights.

This Aristotelian conception of justice as a relational dynamic remains relevant in contemporary debates on social equity, human rights, and distributive justice. For example:

• Social Equity: The idea that justice involves interpersonal relationships and the fair distribution of resources is central to modern discussions on economic inequality and redistribution policies, as seen in analyses by the Journal of Ancient Philosophy (2013) [9]. Nussbaum (2006) [10] expands this perspective by arguing that justice theories should consider not only the distribution of resources but also the recognition of capabilities – echoing Aristotelian emphasis on eudaimonia as the integral flourishing of human potential.

• Human Rights: Aristotle's emphasis on recognizing the other as a subject of rights resonates in contemporary struggles for racial, gender, and social equality, as highlighted in 1000-Word Philosophy (2019) [11]. Indeed, contemporary struggles for recognition (feminism, anti-racism, LGBTQ+ rights) echo the relational dimension of Aristotelian justice: dignity is not an individual property, but an intersubjective construction requiring mutual recognition. Honneth (2003) [12] develops this intuition by showing how the formation of personal identity depends on three forms of recognition – love, rights, and solidarity – which resonate with Aristotle's understanding that virtue only realizes itself in the polis, through relationships with other citizens.

  The ecological crisis raises questions about temporal justice: how to apply Aristotelian principles to intergenerational relations? Responsibility for future generations expands the relational dimension of justice beyond the present.

• Algorithmic Justice: The flexibility of Aristotelian justice, as in the concept of epieikeia (equity), anticipates modern justice systems using artificial intelligence to adjust decisions based on specific contexts, always considering the relationships between parties, as discussed in iPleaders (2022) [13].

3 Equity and Injustice as Mathematical Disproportion

3.1 Context and Background

In his work Nicomachean Ethics, Aristotle dedicates Book V to the discussion of justice, distinguishing it into universal (obedience to laws) and particular (distributive and corrective). Within this structure, he introduces equity as a virtue that corrects the limitations of written law and conceptualizes injustice as a disproportion, using mathematical models to illustrate its forms. These concepts are central to his moral and political philosophy, influencing modern legal and ethical systems.

3.2 Equity (epieikeia) as Correction of the Law

Aristotle defines equity as a virtue that adjusts the rigidity of the law when its literal application would result in injustice. He uses the metaphor of the "lead ruler of Lesbos," a flexible tool used by builders to measure irregular surfaces, to illustrate how equity adapts to the specific circumstances of each case.

Relation to Justice: Equity is a form of justice, but superior to the strict justice of the law. While the law is universal and cannot cover all particular cases, equity intervenes when the mechanical application of the law would lead to unjust results. For example, if a law requires all debtors to pay a fixed amount, but one debtor is in extreme poverty, equity may suggest a reduction or exemption to avoid imbalance.

Characteristics of Equity: It is a moral virtue that requires practical wisdom (phronesis), as it involves the judgment of when and how to apply correction. This is highlighted in the Stanford Encyclopedia of Philosophy (2022) [5], which explains that equity requires discernment and prudence to adapt the law.

It is not a negation of the law, but an enhancement of it, ensuring that the final outcome is truly just. As noted in Academia.edu (2009) [14], equity is a moral competence that goes beyond legal justice.

The equitable person (epieikēs) is one who, even when the law is in their favor, is willing to relinquish something of their right to avoid an unjust result. For example, they might accept less than they are owed to maintain harmony and justice in a relationship, as discussed in Sniggle.net (n.d.) [15].

Practical Examples: Imagine a law that prohibits anyone from entering private property without permission. A man enters a house to save a child from a fire. The strict application of the law could punish him for trespassing, but equity recognizes that his action was just and necessary, correcting the law to avoid injustice.

Another example could be a contract that, due to unforeseen circumstances, would cause significant harm to one party. Equity could allow for the modification or cancellation of the contract to prevent injustice.

Contemporary Relevance: Aristotle’s idea of equity resonates in modern legal systems, such as equity law in the Anglo-Saxon legal system, which allows flexibility in the application of the law to ensure justice in specific cases. Additionally, equity anticipates modern concepts of adaptability, as in artificial intelligence systems that adjust decisions based on particular contexts, as discussed in an article published in Secularpriest (n.d.) [16].

3.3 Injustice as Mathematical Disproportion

Aristotle conceptualizes injustice as a form of disproportion, using mathematical models to illustrate its two main forms of particular justice: distributive and corrective.

Distributive Justice: Involves the distribution of goods, honors, or resources among the members of a community.

It follows a geometric proportion: A/B = C/D, where A and C are the parts received by two individuals, and B and D are their respective merits or contributions. For example, if A contributes twice as much as B, A should receive twice as much as B.

Aristotle’s distributive justice, with its geometric proportion (A/B = C/D), is not just an allocation algorithm but a grammar of social recognition. Each proportion distributes not only material goods but social meanings that define identities and hierarchies—a process that Taylor (1994) [17] identifies as fundamental in contemporary recognition policies, where the distribution of resources is intrinsically linked to the recognition of identities and dignities.

Distributive injustice occurs when goods are not distributed according to each person's merit, resulting in a disproportion between contribution and reward.

Corrective Justice: Deals with transactions between individuals, such as purchases, sales, or loans, and seeks to restore equality when one party is wronged.

It follows an arithmetic proportion: If A takes X from B, corrective justice requires that X be returned from A to B, restoring the initial balance (A + B = C + D). For example, if A steals from B, corrective justice requires A to return what was stolen.

Corrective injustice occurs when this equality is not restored, either by excess (A receives more than they should) or by deficiency (B loses more than they should).

Injustice as Disproportion: In both cases, injustice is a violation of the proper proportions. In distributive justice, it is a geometric disproportion (failure in proportional allocation); in corrective justice, it is an arithmetic disproportion (failure in restoring equality). Aristotle argues that justice is essentially a matter of proportionality, and any deviation from this proportionality constitutes injustice. This is reinforced in an article published by Horn (2006) [18], which discusses how equity corrects these disproportions.

Practical Examples: In a society, two citizens contribute to the common good: A contributes much, while B contributes little. If both receive the same reward, there is distributive injustice, as the proportion between contribution and reward is not maintained (A/B ≠ C/D).

In a transaction, if A sells a defective product to B and does not correct the error, there is corrective injustice, as the initial equality has not been restored.

3.4 Connection between Equity and Disproportion

Equity (epieikeia) is crucial to correct disproportions that may arise from the strict application of the law. Although the law is general and encompassing, it cannot foresee all particular circumstances. Thus:

Equity as Correction:When the strict application of the law would result in a disproportion (injustice), equity intervenes to restore the proper proportion. For example, a law may require all citizens to pay a fixed tax, but if a citizen is in extreme poverty, equity may suggest an exemption or reduction to prevent them from being disproportionately harmed.

This is discussed by Guest (2017) [19], who explores how equity is a virtue that goes beyond legality, ensuring proportionality.

Equity and Proportionality:Equity ensures that the proportions of distributive and corrective justice are maintained in cases where written law fails. It is not a negation of the law, but an adaptation of it to ensure that the final outcome is just and proportional.

3.5 Contemporary Relevance

The metaphor of the "ruler of Lesbos" – a flexible tool that adapts to irregular surfaces – reveals a crucial dimension of Aristotle’s practical philosophy: the irreducibility of the particular to the universal. Equity (epieikeia) is not merely an exception to the rule, but an immanent critique that exposes the limits of all legal formalization.

This conception anticipates contemporary dilemmas about artificial intelligence and algorithmic justice. While automated systems seek consistency through universal rules, Aristotelian equity suggests that genuine justice requires contextual wisdom (phronesis) that no algorithm can fully capture.

Equity faces a performative paradox: to be applied justly, it itself requires criteria that cannot be formalized without contradicting its own nature. The equitable person (epieikēs) must know when to relinquish formal rights, but this wisdom cannot be codified without becoming just another rigid rule.

4. The Paradox of the Ideal Judge: Between Transcendence and Immanence

4.1 Context and Background

In his work Nicomachean Ethics, Aristotle dedicates Book V to the discussion of justice, distinguishing it into universal (obedience to laws) and particular (distributive and corrective). Within this structure, he introduces the judge as the personification of justice, but also recognizes human limitations, creating a central paradox. This tension is explored in sources such as the Stanford Encyclopedia of Philosophy (2022) [5], which discusses Aristotle's ethics, and articles like Dispassionate Judges Encountering Hot-headed Aristotelians (2020) [20], which analyze Aristotle's views on magistrates' emotions.

4.2 The Paradox

The paradox of the ideal judge in Aristotle arises from the expectation that the judge must embody perfect justice, being impartial and just, while the reality is that, as human beings, judges are subject to passions, biases, and personal interests that may compromise their impartiality. This tension is evident in his discussion of corrective justice, where the judge acts as an arbitrator, but also in his emphasis on virtue and practical wisdom.

Personification of Justice: In Nicomachean Ethics, Aristotle suggests that the judge is like the personification of justice, indicating that the judge should be the standard of justice. This implies an idealization of the judge as an impartial being, free from external influences.

Human Limitations: However, Aristotle recognizes that judges, being human, can be influenced by emotions and interests, as discussed in Dispassionate Judges Encountering Hot-headed Aristotelians (2020) [20], which argues that Aristotle emphasizes rational judgment (Section 9, Rhet. 1354a24-6).

This duality creates the paradox: how can a human judge simultaneously be the ideal of justice and susceptible to human flaws? The Stanford Encyclopedia of Philosophy (2022) [5] (Section 5.2) reinforces this, noting that Aristotle’s ethical theory does not offer a decision-making procedure for all situations, depending on practical wisdom (phronesis), which may complicate achieving ideal impartiality.

4.4 Aristotle's Resolution

Aristotle addresses this paradox by emphasizing the importance of practical wisdom, virtue, and equity. He suggests that:

Practical Wisdom (Phronesis): The judge must use practical wisdom, prudence, to discern the just in each case, as indicated in Nicomachean Ethics, where the virtuous person sees the truth in each case, being as a standard and measure for them. This allows the judge to adapt to circumstances, mitigating the impact of biases.

Virtue of Justice: The judge must cultivate the virtue of justice, which includes the capacity to make just and impartial decisions, as addressed in Nicomachean Ethics, where virtue makes the correct aim, the practical wisdom of the things that lead to justice.

Equity (Epieikeia): Aristotle introduces equity as a correction to the rigid application of the law when it would lead to injustice, as detailed in Nicomachean Ethics. This allows the judge to go beyond the letter of the law to achieve true justice, helping to resolve the paradox by offering flexibility.

These strategies do not completely eliminate the paradox but offer a way to approach the ideal while recognizing human limitations.

Practical Examples: Imagine a judge who must decide a commercial dispute case. The law may favor one party due to a literal interpretation, but the judge, using equity, may consider the specific circumstances, such as the financial situation of one of the parties, to avoid injustice, reflecting the tension between the ideal and the reality.

In another case, a judge may be influenced by cultural biases when judging an immigration case, showing how passions can compromise impartiality, illustrating the paradox.

4.5 Contemporary Relevance

4.5.1 The Impossibility of Pure Impartiality

The Aristotelian judge faces a constitutive contradiction: they must embody universal justice while remaining finite and situated. This tension anticipates contemporary debates on legal hermeneutics and critical legal theory. The judge is not a mechanical applicator of rules, but an interpreter who updates normative meanings in specific contexts.

4.5.2 The Affective Dimension of Practical Rationality

Contrary to interpretations that oppose reason and emotion, Aristotle recognizes that practical wisdom integrates affective dimensions. The ideal judge is not dispassionate but has educated passions – anger at injustice, compassion for suffering, indignation at arbitrary inequality.

This insight anticipates contemporary research on moral neuroscience, which shows how emotions are constitutive (and not obstacles) of ethical judgment, revealing a sophistication in Aristotle’s understanding of practical rationality that Ricoeur (1995) [21] rescues by arguing that moral feeling is not an obstacle to moral judgment, but its very texture, echoing Aristotle’s intuition that virtue and affectivity are inseparable.

4.5.3 Algorithmic Justice and Artificial Wisdom

AI algorithms face dilemmas similar to the paradox of the ideal judge: how to program systems that are simultaneously consistent and sensitive to context? Aristotelian phronesis suggests that genuine justice requires situational judgment irreducible to formal rules.

5. The Contradictory Defense of Slavery: When the System Turns Against Itself

5.1 Context and Background [22]

In Politics (Book I), Aristotle argues that slavery is a natural institution and beneficial for certain people. He defines the slave as "one who, being human, is by nature not his own master, but of another" (Politics, 1254a14-18), suggesting that some individuals are "natural slaves" (physei doulos) due to a limited capacity for reasoning. This view is central to his political philosophy but conflicts with other principles, such as his definition of justice and his view of human nature.

5.2 The Defense of Slavery

Aristotle justifies slavery based on the natural hierarchy of the universe, where everything has a purpose (telos). He compares the master-slave relationship to the relationship between soul and body, or between humans and animals, arguing that natural slaves lack deliberative capacity (bouleutikon) and are incapable of living autonomously (Politics, 1254b20-25).

He suggests that this relationship is beneficial, as the slave gains protection and guidance, while the master benefits from the slave's labor.

However, this defense is problematic when analyzed in light of his own philosophy.

5.3 Main Contradictions

Below, we detail the main contradictions in his defense:

5.3.1 Contradiction with Justice as a Relational Virtue

Aristotle defines justice as a relational virtue that only exists in interactions between people and requires reciprocity and proportionality (Nicomachean Ethics, Book V). However:

• Absence of Reciprocity: The relationship between master and slave is not reciprocal. The slave is treated as property or a tool (organon), without rights or autonomy. Aristotle recognizes that justice can only exist where there is reciprocity (Politics, 1255b10-15), but denies this reciprocity to the slave, treating them as an extension of the master (Politics, 1254a14-18). This is a clear contradiction, because if the slave is "part of the master," as he claims, then there can be no justice between them, as justice presupposes two distinct and autonomous parties.

• Disproportionate Treatment: His conception of distributive justice follows a geometric proportion (A/B = C/D), where goods are distributed according to merit or contribution. However, in slavery, the slave receives nothing in return for their labor beyond basic subsistence, and their "contribution" is forced and not voluntary. This does not align with the idea of fair proportionality that Aristotle defends.

• Human Equality: Aristotle recognizes that all humans share the capacity for reasoning (logos), even if to varying degrees (Nicomachean Ethics, 1139a1-5). If slaves are human, as he admits, then they have the capacity for reasoning, which makes them capable of participating in moral and political life. However, by denying them any autonomy or rights, Aristotle contradicts his own view that justice should be based on the shared human nature.

  
  

5.3.2 Contradiction with Human Nature and the Concept of "Natural Slave"

Aristotle argues that natural slaves lack the capacity for deliberation (bouleutikon) and are incapable of living autonomously (Politics, 1254b20-25). However:

• Misidentification of Capacities: He seems to overlook that the intellectual deficiencies he attributes to slaves are the result of their condition of slavery, not an innate characteristic. As noted in 1000-Word Philosophy (2019) [11], Aristotle fails to recognize that slaves' intellectual abilities could be suppressed by the lack of education and opportunities, not by a natural deficiency.

• Inconsistency in Inheriting Traits: Aristotle admits that natural slaves may have children who are naturally free, and vice versa (Politics, 1255b1-5). This suggests that the traits he associates with natural slavery are not consistently hereditary or fixed, weakening his argument that slavery is a natural and immutable condition.

• Conflict with the Definition of Human: Aristotle defines the human being as a rational animal (zoon logon echon), whose essence is reasoning (Nicomachean Ethics, 1098a3-5). If slaves are human, as he acknowledges, then they have the capacity for reasoning, another fact that weakens his theory that there are "natural slaves."

5.3.3 Contradiction with the Practice of Slavery

Aside from theoretical inconsistencies, the practice of slavery in ancient Greece did not align with Aristotle's view of natural slaves:

• Slavery by Conquest: Aristotle admits that many people are enslaved through unjust wars or by convention (nomos), not by nature (physis) (Politics, 1255a1-10). This means that many slaves were not "natural slaves," but victims of circumstances or unjust conquests. This reality contradicts his defense of slavery as a natural institution, as noted by Simpson (2006) [23].

• Diversity Among Slaves: In Aristotle’s Athens, slaves included both Greeks and non-Greeks, "some of whom were educated and capable of reasoning" (Politics, 1255a30-35). This challenges the idea that all slaves are naturally inferior, as discussed by Chua (2014) [24].

  
  

5.3.4 Contradiction with Aristotle’s Political Ideal

Aristotle idealizes the State as a community where citizens actively participate in governance, alternating between ruling and being ruled (Politics, Book III). However:

• Exclusion of Slaves: Slaves are excluded from citizenship and political participation, creating a permanent class of subordinates who cannot contribute to the common good or participate in the ethical and political life of the polis. This contradicts the idea that the State should be a community of equals who alternate in power, as detailed in the Stanford Encyclopedia of Philosophy (2022) [5].

• Absence of Political Reciprocity: The relationship between master and slave is not reciprocal, unlike the relationships between free citizens. This conflicts with Aristotle’s view that the polis is an association of equals striving for the common good, as observed in iPleaders (2022) [13].

  
  

5.3.5 Contradiction with Aristotle’s Ethics

Aristotle's ethics emphasizes the development of virtues and the pursuit of eudaimonia (happiness or human flourishing), which depends on the exercise of reason and moral virtue (Nicomachean Ethics, 1098a1-5). However:

• Slaves and Eudaimonia: Slaves are denied the opportunity to develop their rational and virtuous capacities, which limits their potential to achieve eudaimonia. This is unjust within Aristotle’s own ethical framework, which considers eudaimonia as the ultimate goal of all human beings.

• Friendship and Community: Aristotle argues that friendship (philia) is essential to ethical and political life, but the relationship between master and slave is not a true friendship, as it lacks equality and reciprocity (Nicomachean Ethics, 1159a3-10). This reinforces the idea that slavery is incompatible with Aristotle's ethical ideals, as detailed in Sniggle.net (n.d.) [15].

  
  

5.4 Critical Analysis and Modern Perspectives

Aristotle's defense of slavery is often criticized as a reflection of the prejudices and social norms of his time, rather than a rigorous philosophical analysis.

Aristotle’s defense of slavery is not a biographical accident or cultural concession, but a symptom of internal tensions within his own system. When analyzed structurally, this contradiction reveals how even universalist philosophies can be captured by historical particularities.

Aristotle naturalizes slavery through a hermeneutic circle: he identifies as "naturally slaves" those who have been deprived of education and autonomy by the very institution of slavery. This circular logic anticipates contemporary mechanisms of symbolic violence that Bourdieu (1989) [25] identified as forms of domination that legitimize themselves by making the dominated internalize the categories of perception that naturalize their subordination – a process similar to what Aristotle operates when defending that "natural" slaves lack deliberative capacity.

The concept of the "natural slave" functions as a self-fulfilling prophecy: by denying education and political participation to slaves, Greek society produced the very "evidence" of their intellectual inferiority. This analysis allows for an understanding of how hegemonic epistemologies legitimize social exclusions.

6 Productive Tensions: Learning from Contradictions

6.1 Justice as a Field of Unresolved Tensions

Instead of seeking to resolve Aristotle's contradictions, we propose treating them as productive tensions that illuminate persistent dilemmas. Justice is not a final harmonious state, but a dynamic field where different values (merit/need, universality/particularity, autonomy/community) continuously negotiate.

6.2 Immanent Criticism as Method

Aristotle's contradictions function as immanent criticism: the system itself generates theoretical resources to question its exclusions. Concepts such as reciprocity, universal rationality, and human dignity provide critical tools against slavery and other forms of exclusion.

Final Considerations: Aristotelian Justice Between Legacy and Limitations

The exploration of justice in Nicomachean Ethics reveals both the originality and contradictions of Aristotelian thought, whose influence spans centuries but does not escape fundamental critiques. Aristotle conceives justice as a relational virtue – a moral excellence that is only realized in intersubjectivity, regulating mathematical proportions in the distribution of goods (distributive justice) and in the correction of transgressions (corrective justice). Equity (epieikeia) emerges as its essential corrective, flexibilizing the rigidity of the law to ensure contextual proportionality, guided by phronesis (practical wisdom).

Aristotle teaches us that:

• Justice is always relational: Justice does not exist in isolation but only in the web of relationships that constitutes the social fabric – an insight that Honneth (2003) [12] radicalizes by showing how even self-esteem depends on intersubjective recognition.

• Practical rationality is contextual: Universal principles only realize themselves through particular applications that require situated wisdom – a perspective that Ricoeur (1995) [21] develops by advocating for a moral hermeneutics that integrates universality and particularity.

• Contradictions are productive: Internal tensions within ethical systems are not flaws but engines of moral and political development – a thesis that MacIntyre (2001) [8] explores by showing how ethical traditions renew themselves through internal crises.

• Immanent criticism is possible: Every ethical tradition carries internal resources for self-criticism and transformation – a principle that Taylor (1994) [17] applies by showing how the very modern ideal of universal dignity can critique historical exclusions.

  
  

However, the theory faces unsolvable paradoxes: the ideal judge, embodiment of justice, is undermined by human frailty – passions and biases that compromise impartiality. Even more troubling is the ethical contradiction in the defense of slavery, which denies the reciprocity and rationality inherent in human beings, violating the very principles of relational justice and eudaimonia that Aristotle defends. This incoherence exposes how the prejudices of the time can corrupt even the most robust philosophical systems.

The exploration of internal tensions in the Aristotelian system reveals that its greatness lies not in the definitive resolution of moral problems, but in the articulation of a regulative horizon that guides the ongoing search for a just life.

Aristotelian justice remains an open worksite, where each generation must rebuild, with inherited conceptual materials and its own innovations, the ever-unfinished project of a just society. Its contradictions do not disqualify it, but make it a living interlocutor in trans-temporal dialogues about the meaning of the good life.

Aristotle’s legacy is not a manual of instructions, but an invitation to thought: What kind of life is worth living? What forms of recognition deserve cultivation? How to harmonize demands of moral universality with respect for particularity? These questions, first opened in Stagira 2,400 years ago, remain urgent in our contemporary world.

References

1. The version of Nicomachean Ethics used as the primary reference in this essay is the critical Greek edition established by Ingram Bywater (Oxford Classical Texts, 1894), complemented by translations by António de Castro Caeiro (Instituto Piaget, 2009) and Edson Bini (Edipro, 2017).

2. The distinction between distributive justice (κατὰ ἀναλογίαν, katà analogían – "according to proportion") and corrective justice (ἰσάριθμος, isárithmos – "numerical equality") strictly follows 1131b-1132a in the Bywater edition, with support from Caeiro's notes on the translation of diortotikós ("corrective") in Portuguese (see previous reference).

3. The interpretation of equity (epieikeia) as "correction of the law" (1137a) is based on the debate between Terence Irwin (who defends equity as superior justice) and John McDowell (who sees it as an extension of phronesis), cited in the translation by Christopher Rowe & Sarah Broadie (Oxford University Press, 2002).

4. University of Vermont (n.d.): Justice in the Nicomachean Ethics. Available at: https://www.uvm.edu/~jbailly/courses/clas158/notes/kraut4.html

5. Stanford Encyclopedia of Philosophy (2022): Aristotle’s Ethics. Available at: https://plato.stanford.edu/entries/aristotle-ethics/

6. Alatrsh, R. (2020): Aristotle's Conception of Justice in Nicomachean Ethics and Politics (ResearchGate). Available at: https://www.researchgate.net/publication/341075123_Aristotle%27s_conception_of_justice_in_Nicomachean_Ethics_and_Politics

7. NumberAnalytics (2025): Aristotle's View on Justice: Examining Aristotle's Concept of Justice and Its Differences from Plato. Available at: https://www.numberanalytics.com/blog/aristotle-justice-explained

8. MacIntyre, A. (2001): Depois da Virtude. Translation by Jussara Simões. EDUSC

9. Journal of Ancient Philosophy (2013): Responsibility and Justice in Aristotle’s Non-Voluntary and Mixed Actions. Available at: https://revistas.usp.br/filosofiaantiga/article/download/64451/67152/85198

10. Nussbaum, M. (2006): Frontiers of Justice: Disability, Nationality, Species Membership. Harvard University Press.

11. 1000-Word Philosophy (2019): Aristotle’s Defense of Slavery. Available at: https://1000wordphilosophy.com/2019/09/10/aristotles-defense-of-slavery/

12. Honneth, A. (2003). Luta por Reconhecimento: A Gramática Moral dos Conflitos Sociais. Translation by Luiz Repa. Ed. 34.

13. iPleaders (2022): All about Aristotle's Theory of Justice. Available at: https://blog.ipleaders.in/all-about-aristotles-theory-of-justice/

14. Academia.edu (2009): Epieikeia in Aristotle’s Nicomachean Ethics. Available at: https://www.academia.edu/29949722/Epieikeia_in_Aristotles_Nicomachean_Ethics

15. Sniggle.net (n.d.): Aristotle on Equity, or Epieikeia. Available at: https://sniggle.net/TPL/index5.php?entry=20Oct09

16. Secularpriest (n.d): Equity, a Principle Born out of Necessity in Ancient Times, that Continues to Be an Important Body. Available at: https://www.secularpriest.com/single-post/2017/10/30/equity-a-principle-born-out-of-necessity-in-ancient-times-that-continues-to-be-an-importa

17. Taylor, C. (1994). Multiculturalism and the Politics of Recognition. Princeton University Press.

18. Horn, C. (2006): Epieikeia: The Competence of the Perfectly Just Person in Aristotle (ResearchGate). Available at: https://www.researchgate.net/publication/292357156_Epieikeia_The_competence_of_the_perfectly_just_person_in_Aristotle

19. Guest, J.W. (2017). Justice as Lawfulness and Equity as a Virtue in Aristotle’s Nicomachean Ethics. (Cambridge Core: The Review of Politics. 2017; 79(1):1–22). Available at: https://www.cambridge.org/core/journals/review-of-politics/article/abs/justice-as-lawfulness-and-equity-as-a-virtue-in-aristotles-nicomachean-ethics/E306683AE6C03475FF2EBDA1A2E49FBA

20. Rapp, C. (2020): Dispassionate Judges Encountering Hot-headed Aristotelians (DPSP Annual Volume 1). Available at: https://paulscholten.eu/research/article/dispassionate-judges-encountering-hotheaded-aristotelians-2/

21. Ricoeur, P. (1995). O Justo. Translation by António Hall. Instituto Piaget.

22. The edition of Politics used in this essay is the one edited by August Immanuel Bekker (Aristotelis Opera. Berlin: Georg Reimer, 1831-1870. 5 v.) and available at: https://catalog.perseus.org/catalog/urn:cite:perseus:author.204

23. Simpson, P. (2006): Aristotle's Defensible Defence of Slavery (Polis: The Journal of the Society for Greek Political Thought. 23. 95-115. 10.1163/20512996-90000088). Available at: https://www.researchgate.net/publication/233656685_Aristotle%27s_Defensible_Defence_of_Slavery

24. Chua, A. (2014): A Defence of Aristotle on Natural Slavery (Academia.edu). Available at: https://www.academia.edu/14210092/A_Defence_of_Aristotle_on_Natural_Slavery

25. Bourdieu, P. (1989). O Poder Simbólico. Translation by Fernando Tomaz. Bertrand Brasil.