Education for sustainable development among rich and poor: didactical responses to biopolitical differentiation

Abstract Previous literature informed by biopolitical theory has shown how global education for sustainable development differentiates between populations by assigning different roles, responsibilities, and lifestyles to rich and poor. Taking these arguments as a point of departure, this paper first identifies three different ‘problems’ pertaining to biopolitical differentiation within this literature and then elaborates on potential didactical responses to such problematic differentiation. The suggested didactical responses draw on Judith Butler’s theories of vulnerability, Jacques Rancière’s ideas of a presupposition of equality, and Michel Foucault’s writing on ethics and self-formation. The paper contributes to previous research on biopolitical differentiation in education for sustainable development by suggesting potential didactical responses to the problematics put forth in these works. It also contributes to previous literature on how Butler’s, Rancière’s and Foucault’s theories are relevant to education by relocating the arguments to the context of global implementation of education for sustainable development.


Introduction
UNESCO's recently adopted framework for implementing education for sustainable development (ESD) globally -ESD for 2030 -emphasizes the connection between ESD and life, claiming that ESD contributes 'to the collective survival and prosperity of humanity' (UNESCO 2020 , 47).The framework also stresses that all humans have a responsibility in the current environmental crisis, stating that we must all 'learn to live differently' (6) but also that we must 'learn to live together sustainably on this planet' (iii).Thus, in the framework, global ESD is portrayed as an inclusive project that involves all of humanity, aiming to educate individuals and collectives to change their ways of life.However, the vision to include everyone on equal terms in global implementation of ESD seems problematic, given that the world is highly unequal.
In discussions on global implementation of ESD, some critical scholars have issued warnings that ESD feeds into neoliberalist globalization, which undermines pluralism and leads to homogenization (e.g.Huckle and Wals 2015 ; Jickling and Wals 2008 ;Martínez-Rodríguez, Vilches, and Fernández-Herrería 2018;McKenzie 2012 ).Other scholars have instead suggested that the particular and contextual is often overlooked and that ESD is re-articulated in different ways in different contexts (Bengtsson andÖstman 2013 , 2016 ).In recent research, however, the above-mentioned notion of ESD as an equal and inclusive global project, and the homogenization/particularization divide, are problematized.Instead, it is suggested that local differences are intimately tied up with a global biopolitical pattern of distinctions between different populations and lifestyles (Hellberg and Knutsson 2018 ).
As will be shown in greater detail below, the findings from these biopolitically informed studies suggest that the implementation of ESD rather follows a pattern of global inequality whereby rich and poor populations are educated to become 'sustainable' in very different ways (e.g.Bylund and Knutsson 2020 ;Bylund, Hellberg, and Knutsson 2022 ;Knutsson 2020Knutsson , 2021 ) ).What requires further consideration, provided that one accepts, and is uncomfortable with, these claims about biopolitical differentiation in ESD, is what didactical alternatives there might be.The use of the term 'didactics' in this context is not to be understood as mere 'instruction' , but rather follows the Nordic/German tradition of 'didaktik' , which ranges from learning theories to curriculum theory and is underpinned by (educational) philosophy (e.g.Englund 2004 ).
The aim of this paper is therefore to elaborate on potential didactical responses to biopolitical differentiation in global ESD, drawing on three thinkers in the continental philosophical tradition.This is done by suggesting three responses that take their point of departure in Judith Butler's ( 2004Butler's ( , 2009 ) ) theories on vulnerability, Jacques Rancière's ( 1991Rancière's ( , 1995Rancière's ( , 2004 ) ) theories on inequality, and Michel Foucault's ( 1990Foucault's ( , 1992 ) ) theories on ethics and self-formation.These theories have been chosen as they offer different intellectual resources for addressing 'problems' associated with biopolitical differentiation in ESD.
The paper is not to be read as an explanation of the theories of the above-mentioned scholars in relation to education or ESD.Neither is it to be read as an attempt to find an appropriate method of teaching or 'best practice' .Rather, by elaborating on different didactical responses, the paper follows Van Kessel's argument that the acute environmental crisis demands open-minded consideration that allows for 'educators to consider a variety of conceptual and practical tools' in order to 'try them out with each group of humans they encounter, whether that be students, parents, administration, or politicians' (Van Kessel 2020 , 140).
The paper is situated in the intersection between educational philosophy and ESD -a field that has received increased interest in recent years (e.g.Pedersen et al. 2022 ;Stickney and Skilbeck 2020 ) -and it contributes to previous research mainly in two ways.First, the paper adds to previous research on biopolitical differentiation in global ESD implementation, as referred to above, by elaborating on potential didactical responses to the problematics put forward in these works.Second, the paper draws on previous research discussing the relevance of Butler's (e.g. Fisher 2011 ;Ruti 2017 ;Zembylas 2019 ), Rancière's (e.g. Biesta 2010, 2017 ;Chambers 2013 ;Vlieghe 2018 ), andFoucault's (e.g. Ball 2017 ;Besley 2005 ;Dorzweiler 2021 ) theories to education, but adds to this research by relating the theories to the specific context of global ESD.
The article is organized as follows.The first section presents previous research on biopolitically differentiated ESD and identifies three 'problems' derived from this research.The second section, divided into three sub-sections, elaborates on different didactical responses to the identified 'problems' , based on theories from Butler, Rancière, and Foucault.The final section summarizes and concludes.

Previous research and three 'problems' of biopolitically differentiated ESD
This section presents previous research on biopolitics and, more specifically biopolitical differentiation in ESD.This leads up to the identification of three 'problems' , to which this paper elaborates potential didactical responses.
In Foucauldian theory, biopolitics refers to the government and administration of life at the level of populations (Foucault 1998(Foucault , 2008 ; ;Lemke 2011 ).According to Foucault, biopolitics emerged in the eighteenth century as a power oriented at optimizing and multiplying the lives and ways of life of populations in accordance with certain rationalities (Foucault 1998 ; see also Simons 2006 , 525 -527).In biopolitical theory, the population does not consist of individuals within a geographical or political entity but individuals that are grouped together according to characteristics pertaining to their lives, lifestyles and living conditions.Grouping people together in populations enables differentiation, as 'techniques for maximizing life' (Foucault 1998, 123) can be adapted to suit particular populations' perceived needs, but also to govern their conduct in diverse ways.Thus, divisions and hierarchizations are characteristic of biopolitics since they allow for differentiation among populations between 'good and bad' conduct but also between 'higher and lower' forms of lives and lifestyles (Lemke 2011, 41).
Although the relevance of biopolitical theory for educational research has been widely acknowledged (e.g.Ball 2012 ;Peters and Besley 2007 ), and although Foucauldian theory has been broadly applied in environmental education (EE) and ESD research (e.g.Blewitt 2005 ;Ferreira 2009 ;Fletcher 2015 ;Ideland and Malmberg 2015 ;Pierce 2015 ), biopolitical studies are sparse in EE/ESD.Three notable exceptions are Gough's ( 2017 ) study that explores shifts in EE/ ESD policy discourses, Little's ( 2015 ) study on the educational 'greening' of American prisons, and Shava's ( 2011 ) study of power/knowledge relations in natural resource governance.These studies are examples of how biopolitical theory can be applied in EE/ESD to explore governing of lives, lifestyles and subjectivities.However, how biopolitical distinctions are made between different populations in ESD has not been explored until recently.
These recent studies on biopolitical differentiation show, in various ways, how ESD interventions construct populations as suitable for different forms of ESD, thereby differentiating ESD by adapting it to students' local 'realities' and needs.Knutsson (2021) shows how the international UNESCO-Japan prize on ESD differentiates among the laureates by creating segments of winning projects evenly spread across the lines of income.The study demonstrates how winning organizations adapt their interventions to the socio-economic conditions in which they operate, which leads to rich and poor populations being targeted in very different ways and assigned different roles, responsibilities and environmental subjectivities.In another study, Knutsson (2020) explores how ESD programmes in South Africa handle the abysmal inequality within the country.The elasticity of the notion of sustainable development allows for different ways of governing rich and poor, where some populations are to become sustainable within their local 'reality' of a mass-consumption society and others within their 'reality' of struggles over basic needs.The study contends that inequality is effectively normalized and that the differentiated ESD practices imply a 'depoliticized notion of local "realities" as something isolated and given, rather than relational and produced' (Knutsson 2020, 650).
Such adaptation to unequal living conditions and differentiation between different populations is also evident in the new global UNESCO initiative ESD for 2030 (Bylund, Hellberg, and Knutsson 2022).The framework states that 'ESD approaches need to be contextualized to the realities of target populations' and that 'the approach for populations in extreme poverty may require more attention to the fundamentals' (UNESCO 2020, 59, my emphasis).Thus, people in extreme poverty are singled out to be approached differently, since ESD targeting these populations should prioritize 'basic and other relevant life-skills, or skills to ensure their livelihood' (ibid., my emphasis).ESD for 2030 thus seems to establish a hierarchy of populations constructed as suitable for entirely different interventions in ESD.Apart from this, and more implicitly, ESD for 2030 also establishes a biopolitical hierarchy between humans and other forms of life by presenting humans as separate from, rather than a part of, nature (Bylund, Hellberg, and Knutsson 2022, 45).
From these studies of biopolitical differentiation, three 'problems' can be identified, to which this paper elaborates potential didactical responses.First, biopolitically differentiated ESD seems to establish hierarchies between different human populations, but also between human and other forms of life.In relation to student populations, which is the focus of this paper, ESD establishes a biopolitical hierarchy where wealthier student populations are depicted as suitable for a broader range of ESD interventions, whilst the poorest are suitable for only 'basic' ESD.This hierarchy carries the risk of further amplifying a division of humans into affluent populations enjoying a mass-consumption lifestyle and poor populations destined for a life of securing their livelihood through self-reliance.Second, biopolitically differentiated ESD seems to presuppose inequality, thereby normalizing and reproducing it.When ESD interventions are designed to 'suit' different populations in accordance with their lives and lifestyles, the living conditions of these populations are taken as something stable and natural to which ESD interventions have to adapt.ESD thus fails to recognize and challenge the life-chance gap of rich and poor populations and rather feeds into global patterns of inequality.Third, biopolitically differentiated ESD appears to assign different environmental subjectivities and responsibilities to rich and poor populations.When completely different interventions are designed, ESD seems to allow students to constitute themselves as responsible subjects in very different ways (Hellberg and Knutsson 2018).These three 'problems' lead us to the didactical responses in the next section.

Didactical responses to biopolitically differentiated ESD
If we accept the claim that rich and poor are educated differently in the name of sustainable development, and if we perceive this biopolitical differentiation as problematic, what then are the alternatives?This section elaborates potential didactical responses to biopolitical differentiation in global ESD implementation, informed by theories of Butler, Rancière and Foucault.The responses address the three 'problems' of a biopolitically differentiated ESD provided in the section above, with each of the responses having an emphasis on one of the problems.First, a didactical response drawing on Butler's theories addresses hierarchies between different forms of lives.Second, a didactical response informed by Rancière's thinking addresses naturalization and presupposition of inequality.Third, differentiated subjectivities in ESD implementation is addressed by a didactical response drawing on Foucauldian theory.

Didactics of vulnerability and mourning
This didactical response draws on Judith Butler's theories on vulnerability and addresses the problem that biopolitically differentiated ESD establishes hierarchies between different human populations (which is the main focus of this text), but also between humans and other forms of life.Judith Butler is a philosopher and professor of comparative literature and the author of several influential books within gender studies and social and political thought.In her work on vulnerability and precariousness, she conceptualizes vulnerability as both a generalized condition of human life -a 'common human vulnerability' -but also as differentiated and distributed unequally across the world (Butler 2004(Butler , 2009(Butler , 2012 ) ).This perspective of a shared but unequally distributed vulnerability forms the basis of this didactical response.
The idea of a shared condition of vulnerability puts emphasis on our interdependence with others.This includes both other human beings at a global level as well as our 'relations to the environment and to non-human forms of life' (Butler 2009, 19;see also, Ruti 2017).The argument for a common vulnerability derives from the idea that all humans are susceptible to loss, but also that all humans are dependent upon and made vulnerable to others as we are all 'in some sense in the hands of the other' (Butler 2009, 14).By recognizing one's own vulnerability, Butler opens up for the possibility of identification with others' vulnerability and suggests that our dependency on what is outside ourselves obligates us to preserve and nurture 'all those environmental conditions that make life liveable' (2012, 147; see also, Butler 2009).In ESD, a shared vulnerability can challenge divisions and hierarchies of life by emphasizing the students' interdependency with others, for example by stressing how the loss of forests, biological diversity and arable land anywhere in the world is of relevance to all human beings.This would include teaching that exposes students to pictures, stories and different accounts of suffering and loss in order to make use of the powerful feelings that one experiences when others' vulnerability has been exploited, and how their loss is interconnected with one's own vulnerability and life (see, Ruti 2017, 102-103).This could be one way of challenging students to acknowledge and care for other humans, non-humans, and natural environments, independent of geographical or cultural distances and hierarchies.In this way, recognizing the precariousness of ourselves and others through a common vulnerability might have the potential to become 'the condition of possibility for ethical response and political action that recognizes others and their losses' (Zembylas 2019, 101).
Although Butler argues for a common vulnerability, it does not mean that everyone is equally vulnerable.Rather, Butler emphasizes that vulnerability is allocated differently across the world and that 'precarity' designates the 'politically induced condition in which certain populations suffer from failing social and economic networks of support and become differently exposed to injury, violence, and death ' (2009, 25).A didactical response informed by Butler's work can target such hierarchies of unequally distributed precarity by following Zembylas' (2019) prompt to urge 'students to pay attention to the ways global structures of power as well as the local practices they inhabit create the unequal distribution of precariousness ' (2019, 106).In ESD, this would mean avoiding seeing the local context as isolated, and that students instead carefully explore the relations between their context and others' contexts, i.e. how practices in one place affect other places.This could for example mean that students explore how mass consumption in the global north is dependent upon unequal exchange which produces environmental degradation and precarity elsewhere, and how this unequal exchange and unequal distribution of precarity is upheld by different forms of politics and power relations.It would also include scrutinizing how global structures of power enable differentiated lifestyles that affect humans, non-humans, and the surrounding natural world differently.Such a didactical response would be in line with Fisher's (2011) proposition for a precarious pedagogy that focuses on 'the interdependency and vulnerability that differently characterizes [young people's] lives, instead of seeing their action as strictly individual and divorced from shared conditions' (418).It would also allow students to confront their complicity in others' suffering and injury by asking questions such as follows: Is what is happening so far away from me that I have no responsibility for it?If I do not have a part in producing the suffering of others, am I still in some other way responsible to it?(Butler 2012, 135;Zembylas 2019, 106).
Finally, a didactics that recognizes others' vulnerability and acknowledges the unequal distribution of precariousness has to take into consideration the ability to mourn losses and the possibility that all lives are equally grievable (see Säfström and Östman 2020 ).For Butler, grievability functions as a way to apprehend the living being as living since the value of a life appears only under the condition in which the loss of it actually matters (2009,(14)(15).Thus, to be able to mourn the loss of others is central for recognizing the lives of others and for challenging a biopolitical hierarchy of 'populations who are eminently grievable, and others whose loss is no loss, and who remain ungrievable' (Butler 2009, 24; see also, Butler 2004, 30-32).In pedagogy, mourning can be seen as an important recourse for reflecting on the link between vulnerability and responsibility (Zembylas 2019, 108) and in a didactical response targeting hierarchies in ESD, mourning might carry a radical potential for challenging the division between the different lifestyles of rich and poor populations.Butler (2004) argues that mourning involves the acceptance 'that by the loss one undergoes one will be changed' and that mourning 'has to do with agreeing to undergo transformation' (21).Furthermore, Butler, writing in the aftermath of 9/11, discusses how most Americans probably have experienced something like the loss of their 'first worldism' .This is a loss of a 'certain horizon of experience' of the world itself as an 'entitlement' , and such 'narcissistic and grandiose fantasies must be lost and mourned' (Butler 2004, 39-40).Possibly, the same kind of narcissistic fantasies about the entitlement to earth and the right to live a life that has detrimental effects on other humans and non-human lifeforms must be lost and mourned in ESD if any transformation is to be possible.If we agree that it is not possible to continue to live an excessive mass-consumption lifestyle, with a rich minority of the world population causing the majority of green-house gases, then we have to ask if it is possible to go through a radical change without also mourning the privileges lost.As Butler warns, overcoming grief too quickly and instead turning to acting often results in eradication of an opportunity to change.This can be seen in suggestions that reject actual transformation and instead turn to action, like the swift turn to electrification of cars and airplanes that promises high consumers that they can continue to live as before.If we instead would like to see a real change, didactical practices would need to allow for students to discuss how the 'greening' of mass consumption lifestyles is complicit in masking the problem of relocation of environmental degradation and precarity elsewhere.Thus, focusing on the impossibility of certain lifestyles for a just and equitable future might allow for the possibility for students to mourn the lifestyle they lose, or the lifestyle they dream of but that is never to be realized.This might be one way for ESD to challenge the continuation of divisions in lifestyles and instead work towards transformation.

Didactics presupposing equality
In this didactical response to differentiated ESD, the 'problem' of a presupposition of inequality is addressed through works of Jacques Rancière (1991Rancière ( , 1995Rancière ( , 2004)).Rancière is a French philosopher who has made important contributions to political philosophy, philosophy of education, and aesthetics since the late 20th century.In his work, he opposes theories that depart from, and presuppose, inequality 1 , and instead, takes a starting point in an assumption of basic equality, i.e. that all humans have equal capacity to use their intelligence.Equality, for Rancière, is not the levelling out of existing 'relations of economic dependence' (Rancière 1995, 48) but an assumption or 'presupposition' of equal intelligence; and what can be done is 'to test or verify the assumption in concrete situations' (Biesta 2010, 51).In education, this means that although there are, in Vleighe's (2018) words, 'good (empirically backed up) reasons to believe that we are not equally intelligent, it is still possible to act as if this was the case' (922).
Even though it might seem awkward to presuppose equality in a world that is obviously unequal, the Rancièrian idea of equality as a presupposition offers ways of thinking that can potentially disrupt the current logic of differentiated global ESD that appears to presuppose and adapt to inequality.To start with, categorizations of populations are necessary for differentiated biopolitical interventions to function.For example, the suggestion in ESD for 2030 (UNESCO 2020, 59) to prioritize 'basic life-skills' among poor populations 'to ensure their livelihood' , necessitates that the category of the 'poor' is singled out.Rancière, however constantly contests categorizations starting from inequality and rejects a 'pure category for the poor' (Chambers 2013, 639).This is not because he denies that some groups of people are poor but rather that the confinement of the poor to a proper 'sphere' or category runs the risk of falling into a division of what can be said, felt or perceived by legitimate or illegitimate persons or groups (see Stamp 2013 , 649).Instead, presupposing equality begins by verifying the capacity of everyone to think, speak and act like equals, and by acknowledging that everyone has the same capacity to use their intelligence in communication with others, regardless of access to material resources, thus verifying, 'that they truly belong to the society, that they truly communicate with all in a common space' (Rancière 1995 , 48; see also, Means 2011 ).
In ESD, this would mean adopting a perspective that rejects differentiation between student populations based on some perceived lack of resources or prerequisites.Although inequality certainly exists and provides affluent populations with better access to resources, -e.g.undisrupted schooling, teachers with training, and learning materials -such resources are not necessary for education that assumes equal intelligence.This is so because the argument of a presupposition of equal intelligence is not an argument about intelligence as manifested equally, but one of presuming equal intellectual capacity.Hence, whether more affluent student populations have better prerequisites to manifest their intelligence in ESD is therefore beside the point.Rather, the point is that if we suppose that everyone has equal intellectual capacity, it allows for a rejection of (biopolitical) ESD differentiation on socio-economic grounds, since everyone is presumed to have equal intellectual capacity to read, think and speak, and to have the right to express themselves in different ways (e.g.Simons and Masschelein 2010 , 513).Hence, if a starting point is taken in the presupposition that intellectual capacity is common to all humans, and all humans have the right to be listened to, differentiation seems to be redundant, and a didactical response presupposing equality of intelligence should therefore avoid falling into differentiation that produces some population as suitable only for 'basic skills' for survival in ESD.
Another important aspect of a didactical response rejecting a presupposition of inequality in ESD is to attend to how a perceived hierarchy of intelligence between teacher and student can be challenged in everyday practice.Some leads as to how this could be achieved are to be found in Rancièrés (1991) book The Ignorant Schoolmaster -Five lessons in intellectual emancipation.In the book, Rancière recounts the story of French teacher Joseph Jacotot, who came to reconsider the importance of explication when he was assigned to teach literature to monolingual Flemish students, a language that he did not speak.Although Jacotot could not use his knowledge to explain anything to the students, they managed to learn French solely through careful studies of a bilingual version of Fénelon's novel Le Télémaque.This led Jacotot to contend that knowledge is not necessary for teaching and explication is not necessary for learning.Rather, Jacotot found that the need for explication from a 'superior' master to an 'inferior' student is a 'pedagogical myth' that makes a division between 'ripe minds and immature ones, the capable and the incapable, the intelligent and the stupid' (Rancière 1991, 6).The primary function of explication is thus to demonstrate the distance between the knowledgeable teacher and the ignorant student, a way of telling the student that they cannot learn without the help of the superior intelligence of a master explicator.Hence, explication, or 'the explicative order' is argued by Rancière to render students both dependent and stupid, and is 'the parable of a world divided into knowing minds and ignorant ones' (ibid.).Rancière rejects such hierarchical dependency as it establishes a relationship of inequality between teacher and student and, importantly, projects equality as something belonging to a distant future: 'Never will the student catch up with the master, nor the people with its enlightened elite; but the hope of getting there makes them advance along the good road, the one of perfected explications' (Rancière 1991, 120).
The ideas of Jacotot/Rancière -that education should not be built around an assumption of unequal intelligence between teacher and students -are relevant for thinking of ESD from an equality perspective.Instead of presupposing inequality by practising endless explications, teachers can instead assume that the students can use their intelligence on equal terms and think for themselves.For example, in ESD, UNESCO (2020) emphasizes the themes of transformation and responsibility for the future, and within these topics the need for explications from a teacher with superior knowledge can be questioned.Thinking of transformation and the future must be open to surprises, that there are moments of interruption and possible events that can never be anticipated or known in advance (Chambers 2013, 642).Thus, although there are important knowledges within ESD that can help students to think about and imagine alternative futures, there is arguably no certain knowledge about the future that can be explicated to the students.Since explication from a teacher, in Rancière's argument, always carries the risk of rendering students 'stupid' and lead to students believing that they cannot think about the future for themselves, explication should be used with care.Instead, the role of the teacher in a didactical response presupposing equality in intelligence should not be to provide explications, but rather to constantly encourage students to think for themselves and to verify that the students has used their intelligence.This means that the teacher forbids the student the 'satisfaction of claiming that one is incapable of learning, thinking and acting for oneself' (Biesta 2017, 64).Hence, the relationship between teacher and students should not be one of 'intelligence to intelligence' but of 'will to will' (Rancière 1991, 13).Such a didactics would go 'radically against the given order of things' , not accepting the premise 'that society should be ordered according to well-distinguished, hierarchically distributed roles and positions' (Vlieghe 2018, 924).Rather it would assume that individuals are equal and can think for themselves about environmental and sustainability questions and answer the basic questions that Rancière proposes for an education built on equality: what do you see? what do you think about it?what do you make of it?(Rancière 1991, 23).

Didactics of self-formation
The last didactical response in this paper addresses the problem of different environmental subjectivities assigned to rich and poor populations in global ESD, and draws on Michel Foucault's later work on ethics and self-formation.
In the early 1980s, Foucault (e.g. 1992Foucault (e.g. , 1990) reoriented his work towards ethics and the formation of human subjectivities, as he contended that his earlier work had perhaps insisted too much on technologies of domination and power (Foucault 1988 , 19).This new orientation took as point of departure different practices of ethical self-formation in ancient Greece through a 'care of the self' and 'technologies of the self' .Taking care of the self involves transformation of oneself into a certain mode of being through different technologies, which is an 'enduring engagement in the travails and failures of self-fashioning, experimenting with and choosing what we might be and how we might relate to others' (Ball 2017 , 81; see also Foucault 2000a ).Hence, care of the self is closely connected to the Greek's understanding of ethics as a way of being and acting that cannot be learned without the training of the self by oneself (Foucault 2000d(Foucault , 2000b , 208) , 208).
In educational settings, such training in self-formation might not seem possible, given that education, in Ball's words, is 'a key space of regulation' concerned with 'the manufacture and management of individuals and the population' (Ball 2017 , 2; see also, Ball and Collet-Sabé 2022 ; Leask 2012 ).However, as Foucault (2000a , 167) contends, there are always possibilities for resisting being governed, and a didactics allowing students to challenge pre-determined subjectivities can start in the care of the self, as it is here, 'in our relation to ourselves that we might begin to struggle to think about ourselves differently' (Ball 2017, 75).Although Foucault's writing was not explicitly oriented towards how such care of the self could be practices in the present, his thinking can be used to elaborate on how different technologies of the self could be applied to challenge normalizing ESD and engage students in both individual and collective practices.
Individually, this could for instance mean practising 'self-writing' in the form of individual notebooks (hypomnemata), where things read, heard or thought are gathered for subsequent rereading and reflection (Foucault 2000b; see also, Besley 2005).Such notebooks (or digital blogs, vlogs, or portfolios) are to be close at hand and used whenever possible to reflect on how one's own everyday actions and ways of living affect, and are affected by, others, but also, how this is subject to change.Self-writing in ESD can thus be a 'shaping of the self' that aims at resisting environmental subjectivities coming from outside by bridging the gap between thought and conduct in real situations.For example, the students can add different texts, discourses, and perspectives on ESD to the notebooks and then reflect upon these texts in relation to their actions in everyday life.Such a reflection would aim at mapping out what the students believe to be true in relation to environmental issues, but also how the students can conduct themselves ethically according to such truths.Thus, the use of notebooks in ESD would be an ethical process where students transform 'truth into ethos' (Foucault 2000b, 210), as they critically elaborate on what precepts to follow in relation to environmental issues and decide upon a certain mode of being and acting.In this way, the notebooks represent a way of establishing a relationship to the self and bringing critical reflections on oneself that has to do with the formation of an 'ethical subject' through 'subjectivation' rather than adopting 'codes of behaviour' and already existing subjectivities (Foucault 1992, 28-30).
In a didactical response built on Foucauldian care of the self, individual technologies like the notebooks must also be supplemented with collective technologies, since caring of the self is also a way of caring for relationships with others (Infinito 2003).Foucault emphasizes the link between self and others by stating that 'a person who took proper care of himself would, by the same token, be able to conduct himself properly in relation to others for others' (Foucault 2000d, 287).One way of connecting individual and collective care is the practice of parrhesia, or truth-telling.This could well be one way of challenging the normative idea of an education for sustainable development and the environmental subjectivities that such education aims to produce (cf.Jickling 1992 ).
Parrhesia, for Foucault, means that the speaker should make perfectly clear what s/he knows to be true and dare to tell this truth regardless of the consequences.Furthermore, the speaker must always be in a less powerful position than the interlocutor is, and feel a duty to speak the truth (Foucault 2001 , 11 -20;Peters 2003 ;Hellberg and Knutsson 2018 ).In ESD, practising parrhesia could function as an obligation to criticize.For example, students could speak up against environmental injustices and the unequal distribution of responsibilities that rich and poor populations are assigned in the quest for sustainability.They could also practise criticism towards unsustainable ways of living and how we all play a part in reproducing these conditions within a capitalist economy.The point, however, is not that parrhesia should be centred on certain normative ideas of the environment, but rather allow for the truths produced by students to be spoken out and to be listened to by others.This would be a way for students to practise public criticism that has the potential of affecting both the interlocutor and themselves.Thus, practising parrhesia could potentially allow for a radical ESD where 'the governed addresses the governing' , which would cultivate a willingness to speak the truth and to criticize both 'social conditions' as well as 'oneself' (Ball 2017, 67).
The above-mentioned practices are just two examples of how students can care for themselves and others in ESD, but several other technologies of the self could equally have the potential to challenge predetermined subjectivities (see Ball 2017;Peters 2003).The main idea, regardless of the technologies used, must be that a didactics of self-formation must allow students to transform themselves to live ethically through work with their 'own souls, their own thoughts, their own conduct' (Foucault 2000c , 177).However, whether such self-formation is possible in the normalizing practices of modern education can be seriously disputed.Foucault himself is quite clear when he describes the modern practice of pedagogy as a normalizing practice that imparts knowledge or skills defined in advance to the subjects.Instead, something different would be needed, a practice that Foucault terms 'psychagogy' , which does not 'endow any subject whomsoever with abilities, etcetera, but whose function is to modify the mode of being of the subject to whom we address ourselves' (Foucault 2005 , 407; see also, Dorzweiler 2021 ).Such a non-normative practice seems difficult to achieve though, when students are to be educated for something, as in the case of ESD.Thus, if students are to be allowed to take care of themselves and constitute themselves ethically, there is a need to think education differently (Collet-Sabé and Ball 2022 ).How such an ethical education of self-formation could be organized is important to take into further consideration, because, as Foucault contends, '[t]he risk of dominating others and exercising a tyrannical power over them arises precisely only when one has not taken care of the self and has become the slave of one's desires' (Foucault 2000d, 288).

Conclusions
The present paper has discussed potential didactical responses to problems associated with biopolitical differentiation in global ESD by taking a point of departure in theories of Judith Butler, Jacques Rancière and Michel Foucault.
Drawing on previous research, this paper has argued that differentiation in global ESD implementation is problematic, since it entails a biopolitical division between rich and poor populations.From this previous research, three different 'problems' with differentiated ESD have been identified, to which the paper has suggested didactical responses.The first didactical response, informed by Judith Butler's theories, addresses the problem of hierarchies between different populations in global ESD by suggesting a didactics of vulnerability and mourning that emphasizes the interdependency between different forms of life, but also that unsustainable ways of living potentially must be lost and mourned.The second response addresses the problem of a presupposition of inequality in global ESD by drawing on Rancière's thinking, which instead starts with a presupposition of equality and equal intelligence.The third response, informed by Foucauldian theory on ethics and self-formation, addresses the problem of differently assigned environmental subjectivities between rich and poor populations in global ESD by elaborating on different techniques of self-formation that could possibly allow students to resist efforts to pre-manufacture subjectivity in ESD.
The paper has contributed to previous research on biopolitical differentiation in global ESD by suggesting didactical responses to the problematics put forth in this literature.Furthermore, the paper also draws on arguments from previous research about how Butler's, Rancière's and Foucault's theories are relevant in education, but relocates these arguments to the specific context of global ESD.
The didactical responses in this paper, and the identified 'problems' of biopolitical differentiation in ESD, can be seen in the wider context of educational differentiation.Educational differentiation is not problematic in itself and the argument against biopolitical differentiation in this paper is not an argument for a 'one size fits all' ESD.Rather, educational differentiation can become problematic when it feeds into inequality and establishes hierarchies between different student populations, leaving them with entirely different sets of knowledges and skills, in a way that does not challenge the unequal order of the present (Bylund and Knutsson 2020).This problematic form of differentiation seems to be prominent in ESD and if one is uncomfortable with an education that allows some populations to constitute themselves as 'sustainable' by drinking organic coffee or simply buying and donating a can of tinned food, while others are to constitute themselves as 'sustainable' by searching in rubbish for reusable material, then the didactical responses presented here might be useful to consider (Knutsson 2021;Bylund, Knutsson, and Lindberg forthcoming).
The didactical responses are derived from theories with different ontologies and epistemologies.The responses are also very different didactically, as they range from suggestions om how to teach so that students get more emphatic (see section on Butler), to questions on how students can resist normative education (see section on Foucault).The responses thus incorporate both education that tries to direct students' thinking on ethics in particular directions, which could be argued to be needed in a time of multiple crises, and education that ultimately resists such attempts (see Van Poeck and Östman 2020 ).Hence, it is not possible to synthesize the three didactical responses in order to come up with some general conclusions on how to organize an ESD that responds to biopolitical differentiation.However, and as indicated in the introduction, finding a 'best practice' has not been the purpose of this paper.Rather, returning to Van Kessel's argument, the didactical responses offer some 'conceptual and practical tools' that can be further considered and tried out in different ESD practices and EE/ESD research.How such conceptual (e.g.shared vulnerability, presupposition of equality, self-formation) and practical (e.g.verifying the use of intelligence, practicing mourning, notebooks) tools are to be made relevant is something for educators to reflect upon in relation to their practice.My hope though, is that the didactic responses presented here, and their associated tools, can function as a starting point for considerations and reflections on how we as educators can resist biopolitical differentiation that feeds into, or even reproduces, global patterns of inequality.