Introduction: Just for Kids

But should this be so? Should there be a law just for kids? Is it a necessary and banal truth that children are so different from adults? Is it a necessary and banal truth that the rules and principles that ground justice for children should be different from those for adults? Is a unitary justice for all unachievable? The fact that different standards tend to be used to evaluate and judge what is owed as a matter of justice to children and to adults can turn out to be a problematic diversion from our basic commitments to social justice, especially if liberal egalitarian principles of justice are endorsed.

The core intuition that guides the reflections in this book is that a theory of justice that distinguishes children and adults as categorically different types of humans, with categorically different needs and interests, must be getting something wrong. Especially within theories of justice that commit themselves to protecting the freedom of all, and to treating all as equals, establishing a system (as ours) that systematically restricts the freedoms of children and systematically provides a differential treatment to children would require a very strong justification. How can a theory of justice committed to equal freedom and equal treatment for all humans (which can be termed as liberal egalitarian justice) justify the systematic exclusion of one-quarter of the world’s population categorised as ‘children’ from equal freedom and treatment? This is the core question the book aims to answer.

Throughout its history, liberalism has claimed to endorse equality and freedom for all while systematically excluding certain groups from this freedom and equality, based on their labelling as ‘different’ (think, for example, of liberalism’s historical treatment of women). This has been justified by claiming that, owing to the characteristics, needs, and interests of some groups, it is ‘for their own good’ that they are treated differently. They are too pure, too innocent, too vulnerable, too savage, or too irrational to abide by the principles and rules that govern the rest of the population. I do not intend to claim that all differential treatment is necessarily unjust; however, owing to its history of exclusion and oppression, it might be appropriate to explore whether liberalism’s treatment of ‘children’ perpetuates biased assumptions about their difference that can be used to legitimise unjust and discriminatory practices towards them. Just as we condemn political theories that single out the group of women or of the black-skinned as deserving a differential treatment just because they are ‘women’ or ‘black’, then we must evaluate whether this condemnation might apply to the treatment of children as well.

The fact that a large part of the human population is treated differently merely based on their categorisation as ‘children’ poses an arduous challenge for liberal theories of justice: namely, how can a theory of justice that is grounded on equality and freedom legitimise the treatment of part of its citizenry as unequal and unfree? This book aims to explore the concept of ‘childhood’, its interpretations in contemporary liberal theories, and its translation into the political and legal practice of differential treatment for children. By doing so, it seeks to establish a stronger conceptual and principled foundation for further studies on justice for children, addressing the current lack of alignment between the normative commitments of liberal egalitarianism and the differential treatment of children. It addresses this task by breaking the question into three:

This book argues that children should not be categorised or treated as systematically different from adults. The traits, characteristics, and behaviours that justify differential categorisation and treatment exist throughout the whole life-course and vary greatly from individual to individual. Based on the ideological commitment of liberal egalitarianism to equal treatment and freedom, individuals can only be categorised and treated differently if their personal circumstances require it. An assessment of justified differential categorisation and treatment requires evaluation of the embodied, temporal, and spatial frameworks of the individual to understand what their fundamental interests are and what the appropriate treatment is that is owed to them. This is what I label an ‘adaptive model of childhood’: differential categorisation and treatment requires understanding an individual’s fundamental condition and interests based on their vulnerability (embodied framework), their developmental needs (temporal framework), and their embeddedness in their social environment (spatial framework), all this while accounting for the individual’s status as an agent, with a particular personality, voice, and claims. Strict categories that aim to determine separate regimes of treatment and rights for social groups cannot fully abide by the principles of equal treatment and equal freedom of liberal egalitarianism; only a system that is sensitive to the diverse condition of individuals can live up to the standards of a liberal egalitarian political project.

In this introductory chapter, I provide a brief overview of the main building blocks and milestones in the liberal tradition as it relates to the study of childhood. I then introduce the core aims and objectives that pervade the research carried out in the book, and close by explaining the methods, and the core structure of the book’s parts and chapters.

It might be useful to start with a brief historical overview to clarify the concepts and traditions upon which this book is grounded. Although not in a stable or rigorous manner, children have been a recurring presence in the philosophical literature (Matthews and Turner 1998). Childhood has been studied to understand the inner nature of the human being; as an example of human behaviour in ‘primitive’ societies; and as a source for understanding our development processes, our creation of values, our acquisition of knowledge, and our socialisation mechanisms. Children (and their relationship with their parents) have also been used as a comparative device for understanding political authority and the relationship between citizens and the state. But it was not until the European Enlightenment, especially with Locke’s work on education and Rousseau’s Émile, that childhood started to be studied consistently for what it is, rather than as inspiration and source material for other philosophical and legal matters. How should we understand what ‘childhood’ is? What do our legal and political systems owe to children? How should they be treated, reared, and educated? These became relevant questions in philosophical reflection. The 20th century brought into being the philosophy of education as a rigorous discipline, and the emancipatory political movements in the 1960s and 1970s gave rise to critical theories of childhood. Subsequent decades have made childhood a fundamental subject in liberal political and legal theory and practice, with international treaties such as the 1989 United Nations Convention on the Rights of the Child (UNCRC) framing our current understandings of who children are and what they are owed as subjects of justice.

It is important to start by clarifying some of the key terms that will be used throughout this book: ‘justice’, ‘liberal theory’, ‘liberal egalitarianism’, ‘equality’, and ‘freedom’. ‘Justice’ serves as a fundamental concept in this book, referring to the foundational principle that shapes the interaction between individuals and social institutions (Barry and Matravers 2011). Traditionally, it is encapsulated in its Justinian definition as suum cuique tribuere (‘give to each their own’) (Miller 2023). Interpreted in this manner, justice seeks to explain ‘what is owed to individuals by social institutions?’ and ‘what is the appropriate distribution of benefits and burdens among individuals in a society?’ Here, I refer to ‘justice’ in this wider sense: as the system of laws, practices, and social dynamics that aim to ensure that every individual is treated in the way they deserve. What this treatment entails in practice depends on the particular content that we give to this basic precept.

When we refer to a theory of justice being grounded in the liberal egalitarian tradition, it means that it adheres to a dual normative commitment when determining what is owed to individuals as a matter of justice. First, it upholds the principle of basic equality, which entails treating individuals in the same way, unless relevant circumstances require differential treatment. Secondly, it upholds the principle of basic liberty, which places freedom as a core human interest and requires a justification for any restriction or limit to an individual’s freedoms (Clayton 2002; Tan 2008; Waldron 2017). The principle of basic equality requires a liberal egalitarian theory to ensure that every individual is respected as an equal moral being and treated accordingly. On the other hand, the principle of basic liberty requires a liberal egalitarian to prioritise freedom unless there are compelling reasons to justify restricting it. These two commitments, when combined, form what I will refer to as the principle of basic liberal equality. This establishes a presumption in favour of freedom and assumes equal treatment and respect for all individuals.

Examining justice for children from a liberal egalitarian perspective therefore asks us to understand two issues. First, it involves assessing how our categorisation of children aligns with the principle of basic liberal equality. Second, it entails exploring the appropriate mechanisms needed to accommodate childhood, including its unique needs and interests, within the framework of this principle. By approaching the study of justice for children through a liberal egalitarian lens, I aim to analyse and address these fundamental aspects, striving to ensure that both the principles of basic equality and basic liberty are upheld.

Throughout history, liberal theories of justice and their earlier contractarian predecessors have faced significant challenges in addressing the inclusion of children (i.e., Hobbes [1651] 2009; Rousseau [1762] 1966; Rawls 1999). These theories have traditionally relied on certain assumptions about human traits and behaviours as prerequisites for individuals to be considered as part of a just society. To be bounded by a system of justice, citizens are expected to have roughly equal physical and mental capacities, they must be rational and capable of cooperating with others in order to maintain stable political systems, and they must be capable of consenting to rules as the foundation for legitimising political authority. However, these assumptions have posed a particular dilemma when applied to children, who are believed to possess these qualities to a lesser extent. If we consider traits such as equality, rationality, cooperation, and consent as essential components of all individuals within a just social system, how do we grapple with the inclusion of children, who are often seen as lacking these attributes to a significant degree?

The prevailing approach in the Modern tradition (between the 15th and 19th centuries) was to treat children as exceptions to the established rules. If a theory of justice was deemed correct but incompatible with the concept of childhood, then children were often excluded from its purview. For instance, Thomas Hobbes, regarded as the father of social contract theory, argued that children’s inability to provide consent, likening them to brute beasts, justified their exclusion from being treated as subjects of law and justice (Hobbes [1651] 2009, II.26.8). According to Hobbes, children should be placed under ‘absolute subjection’ to their guardians, granting the latter complete authority over their lives, even including the freedom to kill them (Hobbes [1640] 1928, 23.8). Other philosophers, such as Immanuel Kant and John Stuart Mill, adopted similar approaches, albeit with less radical implications. Kant expressed uncertainty about children’s moral status, casting doubt on their capacity to be regarded as full moral beings entitled to rights (see Zweig 1998). Meanwhile, Mill claimed that affording children the same moral and political treatment as adults would actually be detrimental to their well-being. Thus, he advocated for restrictions on their status as subjects of equality and freedom, claiming it to be in their best interests (Mill [1859] 1961, chapter 18).

John Locke and Jean-Jacques Rousseau are widely recognised as the pioneering thinkers who directly grappled with the challenges of incorporating children into theories of justice. Locke’s Treatise on Education ([1693] 1960) offered the first systematic analysis of what is owed to children, delving into the complexities of assessing their moral and political treatment. He highlighted their potential to become fully-fledged liberal citizens while acknowledging their current limitations in achieving this status. On the other hand, Rousseau’s Émile ([1762] 1979) introduced a unique perspective on justice for children, focusing on their present identity and entitlements as children, rather than merely considering them as future citizens. The contributions of Locke and Rousseau continue to underpin much of the contemporary discourse surrounding the philosophical study of childhood. The questions of how to define ‘childhood’, the role of education and upbringing in shaping our understanding of justice for children, and the specific protections and freedoms they require, are thoroughly examined by both Locke and Rousseau, providing insights that inform the approaches of contemporary liberal theorists to the topic of childhood.

While Locke and Rousseau dedicated more attention to exploring how children could be integrated, at least partially, into liberal political theory than their predecessors or many of their contemporaries, the complexities of including children within liberal theories of justice remained unresolved. Locke focused primarily on the formation of fully realised adult citizens, limiting his account of childhood to the future inclusion of children within liberal theory once they had outgrown their childhood phase. In Rousseau’s case, his conception of ‘childhood’ lacked universality. His ideas of justice for children were exclusively applicable to the privileged and powerful, while also excluding girls from his theoretical framework.

The turn of the 20th century witnessed a significant increase in scientific research on childhood, expanding the range of sources through which children could be examined from political and legal standpoints. This development was largely driven by three disciplines, which emerged in a relatively sequential manner. First, there was a rapid growth in pedagogical theory and philosophy of education during the early decades of the century. This was followed by the advent of cognitive-developmental psychology in the 1930s and the rise of social constructivism and critical theory, including feminism, liberationist pedagogy, and sociology, in the 1960s and 1970s.

The 1910s and 1920s saw the rise of schooling systems based on alternative pedagogical principles that put children and their active participation in their learning process as the centre of concern. Maria Montessori’s theoretical work, and her Casa dei Bambini (school for impoverished children), A. S. Neill’s Summerhill democratic school in the United Kingdom, and Ovide Decroly’s school for children with learning disabilities opened new paths for understanding the varieties and possibilities available to children if allowed more space to explore their abilities and limitations for themselves. Based on his own teaching experience in Chicago, and feeding from the insights that came from Europe, John Dewey’s work on the philosophy of education, and on democratic and pedagogical theory (1920, [1938] 1997) became the new standard for understanding who children were, what was owed to them, and how liberal principles could trickle down and be applied to the life and development process of the younger generations.

In the 1930s, the study of child development and cognitive and moral psychological theories provided fresh perspectives on childhood by empirically analysing how children acquire fundamental human functions, including language, social behaviour, and rational agency. Jean Piaget’s ground-breaking work on the stages of cognitive development in childhood (Piaget [1932] 1965) and Lawrence Kohlberg’s research on moral development (Kohlberg 1984), reaffirming Piaget’s findings, laid the groundwork for a renewed interest in children that extended beyond pedagogical implications to their gradual inclusion in political theory. These studies served as the foundation for understanding the intricate processes of child development, and how children’s cognitive and moral capacities evolve, contributing to their growing recognition as active agents within the realm of political thought.

Social constructivism and its revision of our understanding of the source of concepts and historical narratives had a profound impact on discussions about childhood. Historians such as Philippe Ariès (1962) challenged the notion that childhood and its characteristics were ‘obvious’ and ‘trivial truths’. Ariès argued that the concept of ‘childhood’ itself was a social construct that emerged during the Enlightenment. Before then, he argued, children were treated and perceived in much the same way as adults. This recognition of the diversity of childhood experiences throughout history was further supported by sociological and anthropological research, which explored the various understandings of childhood across different cultures and caregiving traditions (James et al. 1998; Lancy 2015).

The combination of empirical research, influenced by rising neo-Marxist theory and the emancipatory activism of feminism and the civil rights movement, led to a re-evaluation of our assumptions about children, and an acknowledgement of their oppressed condition in social and political contexts. Pedagogical theorists such as Ivan Illich (1970) and Paulo Freire ([1970] 1993) utilised this research to advocate for a system of education liberated from oppressive economic and political forces. Political and social theorists such as Shulamith Firestone (1970), Richard Farson (1974), and John Holt (1974) emphasised the importance of including children in the emancipation efforts of feminists and racial activists, by ensuring that they have equal entitlement to all the rights possessed by the adult population. These thinkers challenged existing power structures and advocated for the empowerment and liberation of children within society.

By the late 20th century, the study of childhood had witnessed significant expansion, both in terms of quantity and sources of information. Gone were the days when only (male) armchair philosophers relied on isolated encounters with a single child to make broad generalisations about childhood. Instead, a more scientific approach emerged, with schoolteachers, psychologists, and sociologists employing rigorous methods to analyse children. This shift towards empirical investigation enabled a more thorough, detailed, and nuanced understanding of childhood.

No longer confined to abstract theorising, scholars now engaged with real children in diverse contexts, using systematic observation, data collection, and analysis. Schoolteachers provided valuable insights into children’s experiences within educational settings, while psychologists delved into cognitive and emotional development, and sociologists explored the social and cultural dimensions of childhood. This multidisciplinary approach fostered a richer understanding of the complexities and variations inherent in the concept of ‘childhood’.

Even if not part of the theoretical research on the topic, the UNCRC (UNGA 1989) holds immense significance as a contribution to the study of childhood in the late 20th century. There are three key reasons why it stands out: First, the UNCRC represented a clear affirmation of children as moral beings deserving equal treatment and recognition as valued members of society. Secondly, its status as the most widely ratified Convention within the United Nations family (all countries but the United States had ratified it by 2023) signified a global consensus on the treatment of children as moral beings with rights. This widespread adoption underscored the importance of addressing children’s rights on a global scale. Thirdly, the UNCRC drew upon the wealth of knowledge accumulated throughout the 20th century, incorporating insights from fields such as psychology, sociology, pedagogy, and political and legal theory. By incorporating these into its provisions, it sought to address pressing questions and challenges that had troubled childhood research, as well as to include children within the framework of liberal egalitarian politics. The UNCRC not only established guidelines for justice about children within the international arena, but also enshrined children as active agents entitled to fair treatment and respect. Unlike earlier perspectives that either viewed children as entirely passive and in need of protection (Modern Liberal theory) or advocated for their complete emancipation from adult authority (Liberationists), the UNCRC emphasised the developmental nature of childhood. It recognised their vulnerabilities, limitations, and evolving capacities, aiming to create a system that protected them while promoting their freedom.

Building upon the principles set forth by the UNCRC, liberal theorists grappled with the philosophical question of how to incorporate children within theories of justice. Scholars such as David Archard, Samantha Brennan, Harry Brighouse, Gareth B. Matthews, Laura Purdy, and Tamar Schapiro, alongside others such as Anca Gheaus, Colin Macleod, Amy Mullin, and Adam Swift in recent years, revisited the Enlightenment-era debates and sought to reconcile the tension between childhood and liberal egalitarian principles. Their cumulative work on childhood, education, and liberal political theory, often referred to as the Standard Liberal view, advocates for the inclusion of children within theories of justice through a careful balancing of their interests as vulnerable and dependent beings with their interests as developing autonomous individuals (Matthews and Mullin 2015; Archard 2016). Rejecting the notion of children as exceptions to liberal justice, the Standard Liberal view explores ways to integrate children within liberal theory while accommodating their unique characteristics and needs.

I have briefly traced the historical development of ‘childhood’ as a topic within liberal political thought, from its sporadic presence in earlier philosophical and jurisprudential literature to its growing significance in contemporary liberal theories of justice, and the influence of empirical research, interdisciplinary approaches, and the UNCRC in setting the current standards for children’s rights. By briefly tracing the historical development of childhood within liberal theory, I have highlighted the evolving understanding of ‘childhood’ and its increasing relevance in contemporary theories of justice. Empirical research, interdisciplinary approaches, and the recognition of children’s rights in the international arena have contributed to a more nuanced and inclusive understanding of justice for children. This sets the groundwork upon which this book is built and for what it aims to achieve: to flesh out the gaps and flaws of current research on childhood and children’s rights within the liberal egalitarian tradition, and to propose a novel view of ‘childhood’ as a concept and of children’s rights as a political and legal practice, in order to open our minds about who children are and how a liberal theory of justice should treat them.

Understanding the concept of ‘childhood’ and determining how children should be treated within a theory of justice is a vital consideration that affects the lives of approximately a quarter of the global population. For a theory of justice to be effective, it must recognise and include all individuals who fall under its authority, aligning its principles of basic equality and freedom with the treatment of children. Accordance between what a liberal theory of justice prescribes and how it treats its citizens is not only an important task; it is its most fundamental task.

Building upon the progress made in childhood studies over the past two centuries, this book delves further into essential questions that lie at the intersection of childhood and liberal theory. While acknowledging the significant strides made by contemporary literature in including children within the framework of liberal theories of justice, this book argues that existing models and theories fall short of providing a fully satisfactory solution for accommodating childhood within liberal egalitarianism. The prevailing accounts presented by the two most prominent liberal positions in the philosophical and jurisprudential literature on childhood and children’s rights—the Standard Liberal and the Liberationist—fail to offer a conception of ‘childhood’, and how children should be treated as holders of rights, in strict accordance with the principles of basic liberal equality. Liberalism demands basic equality and freedom for all, and if children are not included within these core principles, then liberalism is failing to do justice to their needs and interests.

Childhood in Liberal Theory examines the contemporary liberal philosophy of childhood through two of its most prominent strands, the Standard Liberal and the Liberationist approaches. It explores how each of them understands what ‘childhood’ is and how their conceptualisations of ‘childhood’ translate into a particular vision of how children ought to be treated as a matter of justice and concerning their rights.

Standard Liberal theorists have tended to approach these questions by attempting to justify the reasons why children can (and ought to) be categorised and treated as different from adults (Purdy 1992; Brennan 2002; Brighouse 2002; Archard 2004; Gheaus 2015a). Standard Liberals claim that the assessment of children’s status relies on a balancing of their interests as beings who need protection and as developing autonomous individuals. Thus, to do justice to children’s claims, a system of differential categorisation and treatment that ensures them special protections and provisions is required. An alternate, and somewhat disregarded, branch of liberal scholars of childhood, the child liberationists, have argued against this differential status of children, claiming that a truly just political system requires ensuring children the same treatment and status granted to everyone else; that is, children are not different in any relevant way, thus they should be treated in the same way as adults in all aspects of life (Firestone 1970; Farson 1974; Holt 1974; Cohen 1980). While both strands of literature offer valuable insights into the appropriate inclusion of children in theories of justice, neither provides an answer that is fully consistent with the principles of basic equality and freedom.

The Standard Liberal view heavily relies on the differences it perceives as distinguishing children from other humans to justify its departure from basic liberal equality, which renders its normative stance vulnerable. On the other hand, the Liberationist view succumbs to the opposite pitfall by neglecting certain morally relevant traits that necessitate a certain degree of particularism and differentiation in determining what justice demands for some children. Both approaches, in my analysis, inadequately consider the requirements of basic liberal equality. A radical transformation in our conception of ‘childhood’ is necessary to rectify this deficiency.

A revised conception of ‘childhood’ and children’s rights is essential to align our assessment of justice for children with the principle of basic liberal equality. This book puts forth an alternative framework called the adaptive model, which challenges the simplistic approaches of blanket differentiation and blanket equality of previous models. It contends that the moral relevance of ‘childhood’ lies in the intricate interplay between an individual’s embodied, temporal, and spatial conditions, which shape their categorisation and appropriate treatment. The pursuit of basic liberal equality requires treating equal cases alike, demanding an understanding of our differences and how they manifest in the treatment we owe one another.

The adaptive model recognises the significant variations in individuals’ needs and interests arising from their unique relationship with their vulnerability (embodied framework), their developmental needs (temporal framework), and the social context (spatial framework). By comprehending an individual’s condition and their adaptive processes in relation to these frameworks, we gain insights into their treatment as a subject of justice. The model’s primary objective is to provide a conceptual structure that allows us to assess the dynamic relationships individuals have with their bodies, their temporality, and their socio-environmental context. This understanding enables us to determine their interests and how to safeguard them through the provision of rights.

Throughout our lives, we all experience different periods of heightened vulnerability and diverse circumstances that shape our adaptive responses to these vulnerabilities, developmental processes, and environment. There is therefore no fixed, normative definition of ‘childhood’ or predetermined treatment for individuals labelled as ‘children’. Instead, the assessment of the intersections and interactions between an individual and their constitutive frameworks becomes the cornerstone for understanding their needs and the just treatment they deserve.

This book is primarily rooted in philosophical inquiry, drawing upon political, legal, and moral philosophy to examine its hypotheses and arrive at its conclusions. However, it also seeks to overcome certain biases and limitations that have affected the philosophical approach when applied to issues of childhood and children’s rights. To address this, Childhood in Liberal Theory expands its methodological scope by incorporating conceptual and theoretical tools from feminist theory, sociology, and critical legal theory (James et al. 1998; Liebel 2004; Jenks 2005; Cudd 2006; Haslanger 2012). By integrating insights from these disciplines and approaches, the arguments put forth in the book aim to enhance consistency and clarity.

One of the key concerns with the philosophical literature on childhood and children’s rights is its limited responsiveness to the diverse and subjective realities of children’s lives. Recognising this, Childhood in Liberal Theory emphasises the social and biopolitical diversity inherent to childhood as a focal point for its normative evaluation. This requires moving beyond traditional philosophical and jurisprudential approaches to gain a more comprehensive understanding of the nature of ‘childhood’, who children are, and how they should be treated (Cordero Arce 2012).

This book is mostly a work of conceptual and normative analysis grounded both in the methods of reflective equilibrium (Rawls 2001), and social constructivism (Haslanger 2012). The search for reflective equilibrium (henceforth, the reflective method) aims at achieving consistency and coherence between moral judgements about particular issues, and the general principles and normative commitments upon which the particular moral judgements are supposed to stand. Think of it as similar to the search for the surface that most accurately reflects the image of an object. Some surfaces do not reflect at all (a cement wall), others can alter the features of the material object (wavy or rippled water owing to environmental circumstances), some might reflect an incomplete picture (broken or dirty mirrors), some might alter them on purpose (concave or convex mirrors), and some might even take you to opposite worlds (as in Lewis Carroll’s Alice Through the Looking-Glass). The reflective method is the search, in this sense, for a flat, clean, and unaltered reflective surface that best represents the original object. In political and legal theory, it asks what are the most appropriate principles, practices, and concepts (the reflective surface) that ensure the ideal objective we aim to achieve is properly reflected in political and legal practice, and in the lives of individuals.

In this respect, the reflective method assesses the validity of certain moral intuitions, and how particular concepts are used, through an evaluation of their coherence with the general principles of justice in which our particular judgements are grounded. So, if we consider that equality and freedom are basic principles of justice, the reflective method requires us to assess whether the ways in which justice is put into practice (say, by granting and limiting rights to certain groups of the human population) align and are consistent with the general moral commitments we have to equality and freedom. The reflective method is applied at various levels of analysis in this book (see Figure 0.1).

First, it is used to evaluate the coherence and compliance of particular moral intuitions regarding justice for children with general principles of liberal justice. Taking as a given a commitment to liberal egalitarianism, the book assesses whether the moral judgements that pop up when thinking about what is owed to children correspond to the wider commitments one endorses as a liberal theorist. The search for reflective equilibrium, in this sense, asks us to find a route for our judgements about particular issues of justice to cohere and comply with how we conceive of justice in general.

Secondly, the reflective method is applied in a particular way at the level of conceptual analysis to test the validity of concepts in relation to the signified to which they refer. A relevant criticism of John Rawls’s own conception of reflective equilibrium was its lack of concern with ‘facts about the world’ (Daniels 2018): as long as there is consistency between our particular judgements and our general principles, according to Rawls, reflective equilibrium is achieved (Rawls 2001, 30). Here I expand the reflective method in order to test how concepts are used in relation to the actual human traits and behaviours which they intend to refer to. In the case of the concept of ‘childhood’ or ‘children’, for example, the reflective method is used to evaluate whether what is meant by ‘children’ actually corresponds to whom we label as ‘children’, their lived experience and their diverse realities. It thus explores the definitions that structure various conceptions of ‘childhood’ (its characteristics) and considers whether they actually correspond to how they classify and categorise individuals as being ‘children’.

Finally, the book applies the reflective method to highlight what is in a concept and to assess what makes it relevant for discussions about justice. The concepts of ‘vulnerability’, ‘development’, and ‘freedom’, for example, are recurrently used as foundational elements in the evaluation of the legitimate treatment of children: ‘children are particularly vulnerable so they should be protected’, ‘children are unable to act as autonomous agents, thus, can have certain freedoms legitimately restricted’, or ‘children are in the process of development so it is legitimate to treat them differently’. For these claims to make any sense, the concepts that bear the justificatory burden must be meticulously analysed in order to assess what particular features within them bestow them with justificatory relevance in relation to the human subjects they are applied to, and in the context of the general principles of justice under which they are justified.

Social constructivism recognises that any understanding of ‘childhood’ is not solely determined by inherent biological or developmental factors but shaped by social, cultural, and historical contexts. It emphasises that the meaning and significance of ‘childhood’ are socially constructed through language, norms, and practices within a given society (James et al. 1998).

Social constructivism can help our research task in several ways. First, it allows us to critically examine the existing definitions and conceptions of ‘childhood’ within liberal political theory and evaluate their validity. By considering the social construction of ‘childhood’, the book assesses whether these conceptions align with the actual experiences, needs, and diversity of children’s lives. Secondly, social constructivism enables us to investigate how power dynamics, social institutions, and cultural beliefs shape the treatment of children. It enables us, moreover, to explore how societal norms and practices influence the categorisation and treatment of children as different from adults, and to critically evaluate whether these differentiations are justified from a perspective of justice (Cudd 2006; Haslanger 2012).

Moreover, social constructivism encourages us to examine the processes through which social categories, such as ‘childhood’, are maintained, reproduced, and challenged. It allows us to analyse the social and discursive practices that construct and reinforce the boundaries and expectations associated with ‘childhood’. This can shed light on the power dynamics that affect the rights and opportunities of children within society. By incorporating social constructivism, we can uncover the social and cultural factors that shape our understanding of ‘childhood’ and children’s rights. This approach enhances the consistency and depth of the reflective method of analysis, ensuring that the arguments are grounded in a nuanced and context-sensitive understanding of ‘childhood’ and its implications for justice.

Assessing the appropriate inclusion of children within a theory of justice entails a three-step process. First, it involves evaluating the validity of the concept of ‘childhood’ as a social category that determines the status of individuals (see Part I, ‘Defining Childhood’). This section critically examines the concept’s foundations, considering its moral relevance and normative implications. Secondly, it requires elucidating the implications of this social category, specifically regarding the treatment owed to those designated as ‘children’ (see Part II, ‘Grounding Children’s Rights’). Here, the focus is on establishing the grounds for children’s rights and exploring different approaches to address their unique circumstances justly. Lastly, it involves operationalising the developed theoretical framework by demonstrating its applicability to pertinent issues (see Part III, ‘Applying the Adaptive Model’). This section delves into specific contexts, examining how the theoretical framework can inform policies and practices around economic, political, and social issues.

Part I (‘Defining Childhood’) focuses on the conceptual analysis of ‘childhood’ within liberal theories of justice. It begins with an exploration of the concept of ‘childhood’ and its moral relevance for studies on justice (see Chapter 1). It then critically analyses different conceptions of ‘childhood’ in the literature, such as Life-Stage conceptions and the Liberationist view (Chapter 2 and Chapter 3). It highlights the limitations of these models and proposes an alternative understanding of ‘childhood’ (the adaptive model) that takes into account the embodied, temporal, and spatial frameworks that shape children’s lives, and determine an individual’s social categorisation (Chapter 4).

Standing on this conceptual framework, Part II (‘Grounding Children’s Rights’) studies the implications of making use of an adaptive model of ‘childhood’ to explore the theoretical foundations of children’s rights. Vulnerability, development, and embeddedness can greatly affect the just treatment of individuals. This part delves into the discussion of the just treatment of children in terms of their rights. It establishes fundamental interests as the grounds for right-holding and examines the main positions in the literature on the status of children as right-holders. Chapter 5 explores the justification for using a rights-based framework to evaluate the just treatment of children and proposes a capability-based conception of right-holding, drawing on Amartya Sen’s account of capabilities and human value. Chapter 6 and Chapter 7 critically analyse some of the most prominent contemporary liberal approaches to children’s rights (the Standard Liberal, the Liberationist, and the UNCRC), and tests them based on the conceptual structure of Part I and on the groundwork for a theory of rights defended in Chapter 5. Chapter 8 proposes a theory of children’s rights consistent with basic liberal equality, and in accordance with the conception of childhood defended in Part I.

With the conceptual groundwork for childhood and children’s rights established, Part III (‘Applying the Adaptive Model’) operationalises the theory by assessing how an Adaptive theory of children’s rights would fare in particularly thorny cases of children’s rights. It aims to prove the framework’s capacity to normatively prescribe for relevant issues of children’s rights law. Through discussions with the University of Liverpool’s Young People’s Advisory Group, 10- to 19-year-old volunteers who provide a child and youth standpoint to academic research, we came up with three topics that were considered ‘spicy’, ‘controversial’, and relevant for analysing the theory that the book proposes: children’s right to work, children’s right to vote, and children’s rights in public spaces. By establishing the issues as open questions, these chapters aim to explore the justifiability of restricting certain rights and freedoms to children, testing how the book’s theoretical framework fares in particular scenarios, and showing the radical results that come from taking the principle of basic liberal equality seriously.

Childhood in Liberal Theory presses readers to question their most basic assumptions about what ‘childhood’ is, and to revise their moral intuitions regarding the appropriate treatment of children within liberal political theory. It provides an invaluable contribution to contemporary political philosophy through its comprehensive analysis of the status of children in liberal theories of justice, and by proposing a novel and consistent theory on how to best accommodate children within liberal political theory. The book, moreover, expands the breadth of the discussions about childhood within the liberal tradition thanks to its revisiting of the liberationist literature, and to its inclusion of the ample scholarship in the sociology of childhood and in the critical legal theory of children’s rights.