Gerhard Peters

John Woolley

Donald J Trump

Keywords: Antifa, anonymity, leaderless, collective action, personification

What kind of group is Antifa?

The United States 2020 first presidential debate featured a discussion about Antifa. While Biden argued that Antifa is "an idea, not an organization," Trump portrayed it as a "dangerous, radical group." The nature of Antifa sparks disagreements not only in politics but also in scholarly circles. Some view it as a loosely defined label for a fragmented collective.

Others perceive it as a gang or a radical social movement. This article identifies four key factors that make it difficult to define Antifa: the anonymity of its members, the lack of identifiable representatives, the ambiguous affiliation boundaries, and the influence of external agents (including reporters, pundits, and detractors) shaping its identity. Faced with this challenge, I propose stepping back to reevaluate the underlying assumptions of the debate. I seek to complement current theories of social ontology and collective action by introducing an alternative approach centered around the concept of personification.

Introduction

The United States 2020 first presidential debate was marked by a notable discussion on Antifa. While Joe Biden argued that Antifa is "an idea, not an organization," Donald Trump contended that it is a "dangerous, radical group." Trump emphasized, "when a bat hits you over the head, that's not an idea." 1 Beyond the usual hustle and bustle of a presidential campaign, these exchanges raise significant theoretical questions: What constitutes a group agent that intervenes in the political sphere? And more importantly, how are these agents constructed? This article aims to explore these issues by delving into the debate surrounding Antifa. Indeed, disagreements over the nature of Antifa in the United States extend beyond the realm of politics and into scholarly discussions. While some view it as a loose label referring to a disjointed collective, others perceive it as a gang or a radical social movement. This article argues that four factors contribute to the challenges in defining Antifa: the anonymity of its members, the absence of identifiable representatives, the blurred boundaries of belonging, and the influence of external agents (such as reporters, pundits, or detractors) in shaping its definition. Confronted with this predicament, it is necessary to take a step back and examine the ontological assumptions that underpin the ongoing public debate. Because existing theories of social ontology and collective action fail to fully capture the peculiarities of Antifa, this article presents an alternative approach based on the concept of personification.

To answer what kind of entity Antifa is, I argue, we do not need to elucidate the collective intentions that motivate its militants, nor do we need to focus on the ideology inspiring them. Rather, we need to understand the process by which a group can be externally conformed through the rhetorical device of personification. A collective of human beings might be endowed with speech and agency thanks to the intervention of a recognized representative. When a representative speaks and acts with the authorization of the collective, then those words and actions are attributed to the group as a unit. In this case, the representative speaks and acts on behalf of them. But words and actions can also be externally attributed by agents who do not claim to belong to or represent the group. When we apostrophize an entity by attributing to it words and actions that we condemn, we are personifying it from the outside. So, the main goal of this article is to contend that Antifa's participation in the public sphere is constructed through personification. This rhetorical device, I will maintain, tends to become autonomous and to escape the control of its initial handlers.

This inquiry aims to make a two-fold contribution to political science. Firstly, it provides activists and democratically engaged individuals with a conceptual toolkit to comprehend both the potential and challenges related to abandoning traditional forms of representation. Antifa, as a leaderless and decentralized movement operating anonymously, seeks to overcome the drawbacks of conventional politics, such as disengagement resulting from the delegation of power, and the confinement of agency to an elitist ruling class. Antifa leverages an essential democratic value: active participation based on parity and on the absence of hierarchies. However, this horizontal structure is not devoid of obstacles. Whereas the lack of a manifest spokesperson distributes the words and actions of the movement among its several members, it also leaves the door open to interferences from outside stakeholders.

Much like Biden and Trump, interested parties might try to define Antifa's identity according to their own political agenda. The definition of Antifa, I argue, is not inconsequential. If acknowledged as a fully-fledged group, Antifa turns into a collective agent, capable of politically significant action. Again, this offers opportunities but especially risks, in light of the radicalized discourse that presents Antifa as a collective involved in terrorist activities. In this context, my main claim is that the device of personification better equips us to understand how the intervention of non-members can create, disrupt, and consolidate the identity of a movement such as Antifa, jeopardizing its position as a political actor vis-à-vis the public opinion. Practical outcomes of this novel approach will be revisited at the end of the article, with an exploration of the insights it may offer to Antifa militants.

Secondly, on a theoretical level, this endeavor addresses a blind spot in contemporary social ontologyspecifically, its difficulty in accounting for social movements that offer limited information about their collective intentions and commitments. If journalists and political scientists cannot reach an agreement on the nature of Antifa, the movement poses an even greater challenge to philosophical perspectives that otherwise do a good job in explaining collective action. My approach is conceived as a supplement designed to offset this obstacle. Indeed, the focus on attribution of words and actions rather than on shared intentionality opens a promising avenue of analysis, capable of capturing the way identities of social movements are crafted and continuously negotiated. As I shall point out, this investigation can also serve as a model for studying other political phenomena akin to Antifa.

In terms of the argumentation, the plan is as follows. Firstly, I provide a brief overview of the main characteristics of Antifa and explain the challenges in defining it (section 1). Next, I assess the ontological foundations of the Antifa debate and identify their limitations (section 2). Subsequently, I introduce the concept of personification of groups and present an alternative theoretical framework (section 3). This framework encompasses four key analytical dimensions: attribution, performativity, personification, and autonomization. I then conclude that Antifa is indeed a group, that is, a collective agent to which we attribute words and actions, but one that is predominantly portrayed and shaped as such by external actors (section 4). Finally, I draw three valuable insights that Antifa insiders can glean from this approach (section 5).

Antifa: a brief outline

Antifa in political, scholarly, and public debate

Antifa (short for antifascist) is a left-wing movement in the United States of America that pledges for direct action against racism and white supremacy. It first entered the public discourse in 2017, when Antifa supporters successfully prevented the alt-right polemicist Milo Yiannopoulos from speaking at the University of California at Berkeley. Later, during a "Unite the Right" rally in Charlottesville, Virginia, activists identified as Antifa physically confronted white supremacists and allegedly defended other counter protesters. [START_REF] Stockman | Who Were the Counterprotesters in Charlottesville?[END_REF] Inspired by the 20th century German organization Antifaschistische Aktion, the movement considers violent action a legitimate way of countering the surge of the far-right.

Renowned historian of anti-fascism, Mark Bray, highlights a "strategic consensus" within Antifa, describing it as an ideology, identity, tendency, or activity of self-defense. [START_REF] Bray | Antifa: The Anti-Fascist Handbook[END_REF] Their goal is to construct societal taboos against racism, sexism, homophobia, and oppression, which are the bedrocks of fascism. [START_REF] Bray | [END_REF] Nigel Copsey, another specialist on the history of fascism and anti-fascism, emphasizes Antifa's anticapitalism stance, asserting that militant anti-fascism involves ideological opposition to the capitalist state. [START_REF] Copsey | Militant Antifascism: An Alternative (Historical) Reading[END_REF] The TORCH network, associated with the movement but not exhaustive, outlines five basic "points of unity:" disruption of fascism, mistrust of the police and courts, opposition to all forms of oppression and exploitation, personal and collective responsibility to uphold these ideals, and support for like-minded individuals both within and outside the network.

The network operates in "chapters" with no guidelines concerning organization.

However, as point 4 evidences, it upholds a notion of collective identity and accountability.

Antifa militants perceive themselves as doing something together: they share online resources where they explain the best way of setting up an antifascist group, and also embark on the practice of "doxing," that is, of exposing fascist profiles on the internet to shame them. The nature of the group became highly controversial when Donald Trump declared that "[t]he United States of America will be designating ANTIFA as a Terrorist Organization." 6 This discourse escalated during the first US 2020 presidential debate. Joe Biden argued that Antifa is "an idea, not an organization." Conversely, Donald Trump claimed that it "is a dangerous, radical group." "When a bat hits you over the head, that's not an idea." 7 Moreover, he hinted that Antifa is a well-organized movement with the capacity to provoke the protests that followed George Floyd's killing in Minneapolis. Because the group would have mobilized multitudes in order to create chaos, he concluded it should be considered a terrorist organization. On his Twitter account he expressed: "Biden says Antifa is just an idea. Ideas don't assault cops & burn down buildings. Antifa is a domestic terrorist org." 8 Disagreement extends beyond politics, as social science research also highlights the challenge of categorizing Antifa. Gary LaFree considers it an "ill-defined entity" and, like Biden, expresses skepticism about whether Antifa constitutes a group in its current form.9

According to LaFree, individuals associated with Antifa may occasionally channel its disembodied ideology, potentially leading to acts of terrorism. However, when applying the classification scheme of the Global Terrorism Database,10 LaFree concludes that none of the attributed actions can be classified as terrorist attacks. David Pyrooz and James Densley argue that Antifa aligns more closely with a "street gang" rather than a "terrorist group," as factions within Antifa exhibit durable street-oriented groups with intentional illegal behavior central to their collective identity. [START_REF] Pyrooz | On Public Protest, Violence, and Street Gangs[END_REF] In his comprehensive study, Stanislav Vysotsky argues that militant antifascism is best understood as a radical social movement, characterized by a decentralized model of power distribution and prioritizing collective and personal identity development and social activism. [START_REF] Vysotsky | American Antifa: The Tactics, Culture, and Practice of Militant Anti-fascism[END_REF] Moreover, these movements oppose similarly organized groups. 13 Depictions of Antifa in public opinion agree on its puzzling nature. Indeed, it has been characterized as "a loose network of groups and individuals," [START_REF] Kenney | What Antifa Is, What It Isn't, And Why It Matters[END_REF] lacking "the hierarchical structure of formal organizations," [START_REF] Tucker | FBI Director Says Antifa is an Ideology, not an Organization[END_REF] and without "a leader, a defined structure, or membership roles." [START_REF] Bogel | What Is Antifa, the Movement Trump Wants to Declare a Terror Group?[END_REF] Antifa has been deemed notable for its "elusiveness" and secrecy. [START_REF] Hemingway | Roots of Antifa: This 'Idea' Has Violent Consequences[END_REF] All in all, as James Short and Lori Hughes recognize, Antifa leaves us with more questions than answers. 18

Four factors that make definition difficult

Building on research findings on the movement, four factors contribute to the challenge of defining Antifa.

Factor 1. Anonymity: Antifa activists use masks and black attire in demonstrations, known as "black bloc," to protect their identity and avoid legal consequences. This deliberate tactic reflects Antifa's emphasis on collective power rather than individual ego. 19 They also maintain anonymity in their social media interventions. The anonymity on Twitter makes it extremely difficult, if not impossible, to link a specific account, even one openly promoting force, to subsequent acts of violence. [START_REF] Klein | From Twitter to Charlottesville: Analyzing the Fighting Words Between the Alt-Right and Antifa[END_REF] Indeed, it has been argued that anonymity on digital platforms serves an "associational function," enabling the generation, negotiation, and collective action within wider publics. [START_REF] Forestal | The Masked Demos: Associational Anonymity and Democratic Practice[END_REF] From a broader perspective, anonymity can be viewed as a means to challenge surveillance and data mining practices of large corporations. [START_REF] Klein | Routledge Handbook of Contemporary European Social Movements: Protest in Turbulent Times[END_REF] Factor 2. Lack of spokespersons: Antifa, like other networks of affinity groups, operates without leaders or central offices. 23 Adam Klein further explains that Antifa does not have a single spokesperson but instead presents itself as a collective of nameless vigilantes. 24 Twitter, in particular, serves as a platform that amplifies their activity, as witnessed in the months leading up to Charlottesville.25 Factor 4. External definition: Antifa's anonymous, leaderless, and decentralized structure allows outsiders and potential insiders to speak about or on behalf of the group. This is why, Ruth Reader asserts, Antifa is susceptible to "infiltration and misrepresentation." 27 The openness to external definition is worrying as it allows outsiders to modify and delineate Antifa's ambiguous identity. The Anti-Defamation League has raised a similar concern, noting that "violence" by unrelated actors is often "misattributed to Antifa supporters," emphasizing the importance of public, news media, and law enforcement understanding of how Antifa "fits within the larger counter-protest effort." 28 The responsibility of determining what constitutes an Antifa action falls on external agents. Surprisingly, while the media has covered the scapegoating and spread of fake news regarding Antifa, the connection between Factors 1-3 and Factor 4 has not been explored by scholars. 29 Given the seemingly insoluble controversy in social studies surrounding the definition of Antifa, whether as a group, movement, or disjointed collective, it is necessary to take a step back and examine the ontological assumptions at play in this debate. Existing theories of group ontology and collective action can serve as valuable tools to address the four factors that complicate our understanding of Antifa.

Antifa in context

Before embarking on that task, it is worth considering whether the core features of Antifa are unique or shared by other collective formations. In their seminal book on social movements, researchers Donatella Della Porta and Mario Diani, highlight their "decentralized and participatory organizational structures; defense of interpersonal solidarity against the great bureaucracies; and the reclamation of autonomous spaces." [START_REF] Della | Social Movements: An Introduction[END_REF] Additionally, the use of "hidden identities" and "anonymity" can be seen as a specific way to challenge and destabilize power. [START_REF] Porta | Social Movements[END_REF] Equally notable on the matter, Spanish researcher Manuel Castells has identified an "emerging pattern" of "networked social movements" that fueled protests worldwide in the 2010s. [START_REF] Castells | Networks of Outrage and Hope: Social Movements in the Internet Age[END_REF] These movements, characterized by their "multimodal" online and offline networking, do not rely on formal leadership or centralized control, instead maximizing opportunities for participation within "loosely connected networks driven by common goals and shared values." 33 Castells also acknowledges the existence of distorted reports and debates within these movements regarding the misrepresentation of their protests. 34 In the case of the Indignados movement in Spain, the lack of spokespersons posed a challenge for the media, as identifiable "faces" are essential elements of their "storytelling." 35 Mónica Brito Vieira, a political theorist who has thoroughly reflected on the issue of representation, described these horizontal and self-authorized mechanisms as "post-representational," 36 indicative of a departure from traditional politics and the associated issues of distance, hierarchy, inequality, and domination. In like fashion, Paolo Gerbaudo, a sociologist interested in social movements in our digital era, refers to this emerging ideology as "citizenism," which pits self-organized citizens against economic and political oligarchies.

He identifies two symbols associated with this trend: the "mask" popularized by the Anonymous hacker group and the "national flags being waved in demonstrations." 37 In sum, elusiveness, horizontality, lack of clear group boundaries, and a vague identity are not exclusive to Antifa. Rather, Antifa is a paradigmatic and extreme case of a larger phenomenon. However, unlike other movements such as Occupy Wall Street or Indignados in Spain, antifascist activists do not hold horizontal assemblies to reach a consensus decision. 38 They do not seek a unified voice that speaks for the whole collective. 39 Their actions are deliberately fragmented and autonomous. This feature combined with a staunch adherence to anonymity makes Antifa particularly susceptible to external definition.

Nonetheless, a model that succeeds in capturing Antifa's four characteristic factors could be exported to analyze similar collective formations. 36 Mónica Brito Vieira, "Founders and Re-founders: Struggles of Self-authorized Representation," Constellations 22:4 (2015), p. 504. 37 Paolo Gerbaudo, The Mask and the Flag: Populism, Citizenism, and Global Protest (Oxford, UK: OUP, 2017), p. 3. 38 In this respect, see David Graeber, The Democracy Project (New York, NY: Spiegel & Grau, 2013) on "consensus," and Castells, Networks of Outrage, p. 132. 39 See Vysotsky, American Antifa, p. 96. A similar phenomenon can be found in the 2018-2019 Yellow vests movement in France, which, according to Samuel Hayat, "Unrepresentative Claims: Speaking for Oneself in a Social Movement," American Political Science Review 116:3 (2022), p. 1045, operated through "unrepresentative claims," that is, claims such as 'I speak only for myself.' By this means, prominent members avoided portraying themselves as leaders, thus respecting the horizontal setup of the movement, while at the same time they reinforced a specific identity promoted by the collective, namely, the identity embodied by them.

Ontological underpinnings: a corporate agent, an ideology, or a network of overlapping intentions?

Political theorist Colin Hay rightly pointed out that any inquiry into political theory entails underlying assumptions about "what exists politically." 40 Our ontology concerning political reality shapes the areas "where we look for causal mechanisms." 41 Therefore, Antifa's (in)ability to intervene politically depends on a logically prior assumption regarding group ontology and collective action. In what follows, I shall unpack the ontological foundations that underpin the public discussions about Antifa.

Interpreting Antifa as a coordinated and leading force capable of massive actions, as Trump does, presupposes significant assumptions about the nature and capabilities of this collective entity. If Antifa is seen as an active agent, it becomes plausible to hold the group accountable for its alleged harmful actions. Moreover, if those actions are officially classified as terrorism, Antifa could also be labeled as a terrorist organization. Trump appears to view Antifa as a member of the moral community, a collective entity capable of intentional action and, consequently, accountable for its alleged crimes. 42 Are Trump's ontological assumptions about Antifa justified? To conceive of Antifa as a moral agent, it might not be necessary to postulate a mysterious force linking individuals through shared intentionality or a formal decision-making process. Instead, it would suffice to recognize the presence of a distinct structure or network of social relationships within Antifa, which internally guides and limits 40 Colin Hay, "Political Ontology," in The Oxford Handbook of Political Science, Robert Goodin (ed.), (Oxford, UK: OUP, 2011), p. 462. 41 Hay, "Political Ontology," p. 464. 42 For a theory that conceives corporate agents as members of the "moral community," see Peter French, Collective and Corporate Responsibility (New York, NY: Columbia UP, 1984), p. 32. French's paradigmatic account of group agency links corporate intentionality and moral agency to a "corporate internal decision structure" (Collective and Corporate Responsibility, p. 13).

the actions of its members. 43 Nonetheless, Antifa lacks a tangible setup capable of ensuring that the collective actions of its militants align with the objectives of the whole group. There are some guidelines and moral pledges, but no representative (Factor 2) or established plan of action. In fact, Antifa would not even qualify as a "plural subject" or "collective agent" in the less demanding model proposed by Margaret Gilbert, which relies on the existence of "joint commitments." [START_REF] Gilbert | Joint Commitment: How we Make the Social World[END_REF] When individuals commit jointly to do something, they create an obligation to act as a unified entity: every member "espouses" a certain goal as a group endeavor and acts "in a way appropriate to the achievement of that goal." 45 Antifa activists, however, are not in a position to make such a joint commitment. The anonymity of its membership (Factor 1) and the difficulty in identifying who is a member and who is not (Factor 3), hinder their ability to intend to pursue a specific course of action as a unit. Consequently, when Trump labels Antifa a "terrorist organization," his characterization appears to impose an exaggerated sense of corporate ontology onto the group. At most, one could consider Antifa activists as dedicated to a certain ethos, or a shared lifestyle, but not to a clearly defined collective undertaking. [START_REF]Social Ontology: Collective Intentionality and Group Agents[END_REF] On the opposite side, by claiming that Antifa is only "an idea, not an organization," Biden indicated that it is not a genuine collective, but an arbitrary aggregate of individuals persuaded by anti-fascist tenets. Ideologies, however, hinge upon collective formations.

According to Michael Freeden, a leading authority on the matter, "transmitters of ideologies" differ from philosophers by mobilizing "significant groups" to gain control over "political language and collective decision-making." [START_REF] Freeden | Ideology: A Very Short Introduction[END_REF] If Antifa is a political idea, it cannot be severed from its practical dimension: the people who struggle to advance it. Furthermore, the absence of a clearly structured organization within Antifa does not imply its reduction to intangible ideas. Individuals can engage in isolated actions that yield collective outcomes.

Christopher Kutz, a moral philosopher specializing in questions of collective agency, offers a key to unravel this conundrum through his "minimalist conception of joint action." 48 Kutz focuses on events involving the intervention of multiple individuals. If, in the context of such an event, the intentions of the individuals "overlap," it is appropriate to characterize it as a joint action. Crucially, this overlap does not demand that they perceive themselves as a group; it suffices that each individual's intention, while pursuing their actions, aligns towards the same outcome. Then, individuals can be regarded as acting collectively, irrespective of their particular "causal contributions." 49 Some might have played a major role, others done very little, but what unifies them is the fact that a similar goal overlapped in their intentions.

In the case of Antifa activists, one might argue that they possess the intention to participate in a loosely defined antifascist mission, thus converging in a collective endeavor. In this sense, the content of the militants' intentions is collectively shared by overlap -everyone roughly holds the same goal. Yet, it is important to note that the agents executing these actions are still the individuals, not a collective entity. Within this framework, Antifa activists would be "hypercommitted" to a cause that necessitates collective fulfillment but remain unaware of the actual participants engaged in it. 50 This brings us to a paradoxical scenario. Given the collaborative effort required to defeat fascism, individual militants are bound to hope that the intentions of their counterparts will overlap with theirs in this struggle, even though they cannot be sure about it. While it may be true that Antifa militants participate in joint actions, 48 Christopher Kutz, Complicity (Cambridge, UK: CUP, 2000), p. 90. 49 Kutz, Complicity, p. 94. 50 I borrow the term from Scott Shapiro, who notes that this conception requires "too great a commitment on behalf of the participants in a shared activity." See Scott Shapiro, "Massively Shared Agency," in Rational and social agency: The philosophy of Michael Bratman, Manuel Vargas and Gideon Yaffe (eds.), (Oxford, UK: OUP, 2014), p. 277. the fact that they are sharing an action remains debatable. They could either be implicated in a widespread subversion, as in "Project Mayhem" in the movie Fight Club (1999), or conducting a solo fight, as Hiroo Onoda, the Japanese soldier who fought for almost three decades after the end of World War II hidden in the Philippine jungle. 51 On the whole, Antifa's collective nature appears to be approachable only in negative terms. 52 It cannot be categorized as a corporate agent due to the absence of a unifying structure, such as a plan, coordinator, or joint commitment. Fragmentation seems to prevail over grouphood. Antifa activists are wary of leadership figures and of prominent incarnations of the group's voice. The movement adopts non-hierarchical and decentralized forms of organization, assembling in autonomous "chapters" and sharing do-it-yourself resources online. Anonymity is prioritized for protection. Even when focusing on individual activists and on the collective component of their intentions, it is hard to elucidate what is that they share. Their fight appears localized. So, whatever they perceive they are doing together, in a we-mode format, it is more contingent than coordinated. However, there is a dimension we have yet to consider.

Regardless of how it is experienced internally by its members, we cannot overlook the fact that Antifa appears in the public eye as a collective entity. While reporters, pundits and detractors engage in characterizations of Antifa, the group remains notably devoid of spokespersons. Certainly, militants can and do express their views anonymously and in a decentralized manner. But because nobody owns, nor disowns, the words and actions attributed to it, much of the external imputations end up shaping the group's perceived 51 Under this understanding militants would, as Olivier Roy and Anne Schwenkenbecher argue, "intend to contribute to a shared (or public) plan but otherwise know little or nothing about other participating agents' intentions." See Olivier Roy and Anne Schwenkenbecher, "Shared Intentions, Loose Groups, and Pooled Knowledge," Synthese 198:5 (2019), p. 4538. 52 Indeed, it could be conceptualized as a "nonmovement," drawing on the insights of Asef Bayat, renowned for his incisive analysis of the Arab Spring phenomenon. Bayat describes nonmovements as "collective actions of noncollective actors" engaged in "fragmented but similar activities" aimed at challenging the status quo. See Asef Bayat, Life as Politics: How Ordinary People Change the Middle East (Stanford, CA: SUP, 2013), p. 15.

identity. This exogenous operation proves elusive to the above parsed theories of collective agency. Indeed, what appears to unite all Antifa activists together is the external definition of outsiders reporting or denouncing the movement's activities, rather than a tenuous notion of a common undertaking. 53 Despite rich debates in social research and in theories of collective agency, none adequately capture this phenomenon. In the next section, I will pursue an approach capable of describing the four factors that obscure the analysis.

A personification approach

To present an alternative perspective and elucidate why Antifa can be perceived as a group, I will delineate four pivotal dimensions of analysis: attribution, performativity, personification, and autonomization. Together, these components form what I refer to as a personification approach.

Attribution: A Hobbesian insight

The first feature of my perspective is a focus on attribution of words and actions rather than on shared intentions or commitments. This is a Hobbesian insight. Thomas Hobbes defines a person as "he whose words or actions are considered either as his own, or as representing the words or actions of an other man, or of any other thing to whom they are attributed, whether truly or by fiction." 54 Being a person depends on external attribution. Individuals are deemed "natural persons" when they are seen as speaking and acting on their own behalf, while they 53 Pace Erskine's criterion of self-assertion that "disqualify[ies] groups that do not see themselves as units," Antifa might be a group that is mainly "externally defined." See Toni Erskine, "Assigning Responsibilities to Institutional Moral Agents: the Case of States and Quasi-states," Ethics & International Affairs 15:2 (2001), p. 72. 54 Thomas Hobbes, Leviathan, Noel Malcolm (ed.), (Oxford: OUP, 2012), p. 244, my emphasis. become representatives or "artificial persons" when speaking and acting on behalf of others or things. Personhood is thus acquired through the attribution of words and actions by a third party, namely, an audience. If observers perceive that the entity in question conducts itself as a person, then it is a person. No metaphysical commitment is attached to the notion. Furthermore, Hobbes also suggests that "there are few things of which there may not be persons," 55 meaning that personhood can be attributed to a range of entities, encompassing not only human beings, but also groups, institutions, buildings, idols, and even God. The crucial point is that being a person relies on intersubjective considerations. Groups, in particular, are persons whose words and actions are attributed to them "by fiction." 56 This means that they cannot really own the words and actions we perceive as coming from them.

To be sure, the French state does not have a mouth to utter statements nor hands to enforce laws, even if we fashion it as the woman, Marianne, featured in official imagery, from the Seal of the Republic to the statues presiding over the farthest towns in the provinces. It is through its principal representative, Emmanuel Macron, and the myriad of functionaries circumvent the challenge of elucidating what is that Antifa activists collectively intend (if such collective content exists at all). 59

Performativity: the role of the audience

Performativity is the flipside of attribution. When the public believes that something is worth being attributed speech and agency, it confers personhood upon that thing. Attribution of words and actions transforms eo ipso an object into a person. In this respect, it is useful to draw upon American philosopher John Searle's concept of "status function declarations." 60 According to Searle, these declarations "change the world by declaring that a state of affairs exists and thus bringing that state of affairs into existence." 61 By means of an assertion of this kind, the nature of a group can be transformed. For instance, the USA President's declaration that 'Antifa counts as a group capable of performing terrorist acts' performatively modifies the reality of the individuals pursuing an antifascist struggle in America. 62 Following that utterance, Antifa activists will probably be taken for a group with terrorist tendencies by several people in Trump's camp. It is important to note that for status functions to work, it is necessary a "collective recognition." 63 Antifa will only be considered a collective terrorist agent if there is a relevant audience that recognize it as such. As Searle elaborates, this recognition can vary, ranging from enthusiastic endorsement to mere acquiescence with the established narrative. 64 Additionally, not every person who utters a status function will alternative reading can be found in Johan Olsthoorn, "Leviathan Inc.: Hobbes on the nature and person of the state," History of European Ideas, 47:1 (2021), pp. 17-32. 59 As Sean Fleming, Leviathan on a Leash (Princeton, NJ: PUP, 2020), p. 108, claims, "the Hobbesian account of attribution… eliminates the need to posit corporate intentions." 60 John Searle, Making the Social World. The Structure of Human Civilization (Oxford, UK: OUP, 2010), p. 13. 61 Searle, Making the Social World, p. 12. 62 Groups, Searle grants it in Making the Social World, pp. 99-100, pose a "puzzling case" because "we need to specify not just that the function exists, but that there is an entity Y, the corporation, that has the function." It is worth noting that Searle's status function declaration puts the creation of "the United States Army" on a par with "the Mafia, Al Qaeda, and the Squaw Valley Ski Team" (Ibid., p. 100). 63 Ibid., pp. 57-59. 64 Ibid., p. 57. automatically be heeded. The "performative utterance" implies an overt claim to possess certain socially sanctioned power, namely the power "to act on the social world through words," in Pierre Bourdieu's terms. [START_REF] Bourdieu | Language and symbolic power[END_REF] In parallel terms, political theorists Christian List and Philip Pettit reject an "intrinsicist conception of personhood" and put forward a "performative" one. [START_REF] List | Group Agency: The Possibility, Design, and Status of Corporate Agents[END_REF] In their perspective, "a person is not what the agent is but what the agent does; the mark of personhood is the ability to play a certain role, to perform in a certain way." 67 When something behaves as a person, we may well call it a person. Appropriately, they dub this approach "Hobbesian." [START_REF] Pettit | See also Marko Simendic, "Thomas Hobbes's person as persona and 'intelligent substance[END_REF] Delving into a closely related terrain, Andrew Rehfeld investigates the mechanism by which we designate a political leader as a representative of a nation in the international arena. He argues that "political representation arises" when "a relevant audience" accepts a person as such. 69 States, NGOs, and other non-state actors speak and act through their representatives as long as "the relevant parties" in each "particular case of representation" recognize them as representatives. Upon specifying an audience, a defined "set of Functions" ensues. 70 The audience will use rules of recognition available to decide if the subject in question is performing its role correctly. Rehfeld illustrates the point with an analogy to the representation of Hamlet. The "audience" here would be a "combination" of the play's producer and the spectators. 71 For the portrayal to be convincing, they should perceive the actor as embodying Hamlet in accordance with distinctive rules germane to theatrical representation. Both these theories evince the importance of the audience in the attribution of words and actions. However, they overlook two vital factors. Searle's focus is on "institutional facts," which are facts established through "human agreement or acceptance" such as the foundation of a company. 72 He asserts that the formation of a group relies on collective recognition, but he neglects the scenario in which declarations of recognition are distributed among the audience. In these instances, the audience's role is active rather than passive. On the other hand, List and Pettit, along with Rehfeld, concentrate on a specific case of attribution: that which occurs through representation. According to their model, if an audience attributes words and actions to a collective entity, it is through a representative claiming to speak and act on its behalf. But not all attributions of words and actions involve representation. As a matter of fact, we are interested in the attribution of speech and agency to a movement that lacks representatives. In the following subsections, I will attempt to address both omissions.

Personification, not representation

As mentioned earlier, Antifa operates without designated spokespersons. So, how can we explain the attribution of speech and action to a thing without drawing on representation? The answer lies in personification, a figure that can be traced back to the rhetorician Quintilian (c.

35-c.100 CE

). He defined it as "a device which lends wonderful variety and animation to oratory," allowing "to bring down the gods from heaven and raise the dead, while cities also and peoples may find a voice." 73 Personification, when applied, bestows speech and agency to voiceless entities, including collectives. Scholars in literary studies have explored this feature of personification, highlighting its peculiar ability to transform abstract notions into 72 Searle, Making the Social World, p. 10. 73 Quintilian, Institutio Oratoria, Harold Butler (ed.), (Cambridge, MA: Harvard UP, 1922), p. 391. tangible agents. 74 Thanks to the device of personification, concepts like liberty, power, the virtues and vices, and even states and nations, take on concrete forms, as characters in a narrative. 75 Importantly, personification transcends the confines of literary works, influencing everyday sense-making. 76 In the domain of foreign policy, states often undergo personification, 77 while corporations acquire distinct personalities through well-crafted branding campaigns. 78 Within the context of conspiracy narratives, groups accused of wielding economic and political power are regularly personified, portrayed as almighty collective agents. 79 Even advanced electronic devices, such as Amazon's Alexa, engage in a sociable manner, prompting users to treat them as person-like entities. 80 Philosopher Achille Mbembe noted that our current era is signaled by the coexistence of "electronic reason and computational media" and a "return of animism." 81 Due to their growing complexity, we tend to conceptualize artifact as persons. Philosopher Sheryl Hamilton adds depth to this discussion with her exploration of the "technologies of personification," notably, our legal systems, that attempt to delineate boundaries between the categories of "person and nonperson." 82 Hamilton concentrates on "liminal beings," including women, corporations, 74 See James Paxson, The Poetics of Personification (Cambridge, UK: CUP, 1994), p. 39. 75 Andrew Escobedo, Volition's Face (Notre Dame, IN: UNDP, 2017), p. 15, notes that personification connects "the order of being to the order of doing," enabling "inanimate things, such as passions, abstract ideas, and rivers," to "perform actions in the landscape of the narrative." 76 As a caveat, I am not addressing personification in the context of spontaneous metaphors, for instance, "my car refused to start this morning." Aletta Dorst, "Personification in Discourse: Linguistic Forms, Conceptual Structures and Communicative Functions," Language and Literature 20:2 (2011), p. 122, clarifies: "conventional personifications can occur on a purely linguistic level without the need for these words to be processed as personifications." computers, clones, and celebrities, all falling short of full legal personhood, yet consistently subject to personification. 83 Things can be persons even if not fitting entirely the typology envisaged by the law. According to Hamilton, the difficulty of applying the juridical form of personhood to these entities sheds light on its constructed nature and its normative power, prompting the need for critical examination. 84 In summary, personification plays a crucial role in attributing speech and action to various entities, whether in fiction and in the actual world. Importantly, one key function of personification is to enable the speaker to address and enter into a dialogue with the personified entity. That is, not to represent it, but to apostrophize it. [START_REF]This aligns with Paul De Man's perspective on apostrophe, where prosopopoeia is seen as the fiction of addressing an absent, deceased, or voiceless entity. See The Rhetoric of Romanticism[END_REF] The underlying idea is that when we direct our pleas, reproaches, or praises to an inanimate entity, we are by that very means personifying it and allowing it to respond. This mechanism, both external and non-representational, of constituting political persons tackles what the models of Rehfeld and or her. Importantly, "the dummy never speaks or acts for or in the name of his vent," instead, it is "supposed to speak or act for himself." 90 The next subsection will delve into the status of personifications whose words and actions are externally attributed, akin to how ventriloquists orchestrate the speech and action of their dummies.

Autonomization

Personification emerges as a highly relevant tool to an era marked by the rapid spread of unverified and unsubstantiated information through unofficial channels, accompanied by a broader skepticism towards mainstream media and academic expertise. 91 A notable illustration of this phenomenon is the proliferation of fake news, characterized by messages with sketchy facticity, intentionally crafted to deceive, and formulated in accordance with the journalistic genre. 92 In this scenario, a political actor, say X, may intentionally generate false news on social media to portray their opponent, Y, as a terrorist. From my model's perspective, this operation can be explained as follows: X demonizes and personifies Y by unjustifiably attributing words and actions to them. Yet, as media scholar Ethan Zuckerman points out, the "participatory nature of contemporary internet" complicates things. 93 Individuals formerly occupying the role of the audience now actively contribute as content creators. 94 This means that anonymous users from different internet ecosystems can expand existing narratives regarding the demonized group. By means of this "decentralized storytelling" the act of personification ceases to be a controlled exercise and autonomizes 90 Ibid. 91 For an argument on this respect, see Matthew Hannah, "QAnon and the Information Dark Age," First Monday 26:2 (2021), p. 2. 92 I extract these characteristics from the work of Jana Egelhofer and Sophie Lecheler, "Fake News as a Two-Dimensional Phenomenon: A framework and research agenda," Annals of the International Communication Association 43:2 (2019), p. 99. 93 Ethan Zuckerman, "QAnon and the Emergence of the Unreal," Journal of Design and Science 6:6 (2019), p. 5. 94 Zuckerman, "QAnon," p. 7. from its initial creator. 95 The distinction between the ventriloquist and the audience that collectively recognizes the role of an entity as a person becomes increasingly blurred, a nuance overlooked in Searle's analysis. It is important to note that this is an open, fluid process, subject to constant iterations, as described by Leonhard Dobusch and Dennis Schoenborn in their study on the hacktivist group Anonymous. 96 The autonomized identity of the group evolves as it is "negotiated" by militants and detractors through "claims on what the organization is and what it is not." 97 In essence, autonomization is the logical outcome of personification. When we attribute words and actions to a figure or a group, we bestow upon them the status of entities capable of independent speech and action. This attribution often takes the form of an apostrophe, employed not only for praise but primarily for reproach, admonishment, or even demonization of the person or group in question. The purpose of this subsection has been to

show how the process of external personification can very easily spiral out of hand. While some actors might leverage specific traits of a personification, they lack control over the avalanche of words and actions subsequently attached to it by other ventriloquists, particularly in the absence representatives who can disown such expressions. As a result, the personification accumulates traits unintended from the outset. Ultimately, the identity of the group undergoes constant negotiation among the actors involved in this ventriloquism process.

4. An answer to the question 95 Ibid., p. 6. 96 Leonhard Dobusch and Dennis Schoenborn, "Fluidity, Identity, and Organizationality: The Communicative Constitution of Anonymous," Journal of Management Studies 52:8 (2015), p. 1006. 97 Dobusch & Schoenborn, "Fluidity, identity, and organizationality," p. 1010.

We can now revisit our initial question and provide an answer: What kind of group is Antifa? Sociologically speaking, Antifa is a loosely organized group comprising clandestine activists engaged in street protests and social media campaigns. Due to their deliberate avoidance of a specific definition beyond a general commitment to antifascism, one might even classify Antifa as a nonmovement. Thus, we end with a mainly negative definition. When building upon theories of collective action to discern the shared intentions of American antifascist activists, we encounter an equally elusive object. Nonetheless, a more comprehensive answer can be articulated by closely considering the four axes of analysis presented. First and foremost is attribution. To determine whether Antifa is a collective person we must assess the attribution of words and actions to it. Antifa duly satisfies this criterion, as a broad set of actions has been imputed to the movementfrom "punching Nazis in the face" to black bloc tactics, doxing, [START_REF] Luke | The Nazi-Puncher's Dilemma[END_REF] "inciting violence or endangering the public," [START_REF] Pelosi | Statement Condemning Antifa Violence in Berkeley[END_REF] defending peaceful demonstrators from white supremacists, 100 organizing massive protests, engaging in terrorist acts, and even storming the Capitol on January 6, 2021. 101 Next, we turn to performativity. When words and actions are attributed to an indefinite aggregate of individuals, that multitude automatically assumes personhood and agency. Given the extensive attribution of words and actions, Antifa is in effect construed as a person, namely, an entity capable of speaking and acting. This perception is not confined to a few individuals harboring conspiratorial delusions. Following Searle's terminology, Antifa is "collectively recognized" as a person. In fact, the definition of Antifa is more shaped by external actors, such as journalists, commentators, and adversaries, than by its own members. Third, personification. Attribution can take the form of representation, where words and actions are ascribed to a collective person through a representative who speaks and acts on its behalf. However, Antifa lacks such representatives. Indeed, the movement's expressions and activities are mainly ventriloquized by external agents who exploit its nonhierarchical and clandestine structure, without an equivalent level of pushback from Antifa's actual members. When public opinion and, most eminently, the president of the United States, embark on a definition Antifa, they conjure up a personhood externally. Through apostrophe, they assign specific words and actions to the movement, thereby altering its identity. In short, Antifa is not represented but rather apostrophized and demonized.

Fourth, autonomization. The process of external personification is not linear but marked by iteration and the active participation of the audience. Numerous actors play a part in shaping the group's personhood, including actual members, reporters, and political opponents. The widespread circulation of unfounded rumors about Antifa, the difficulty of tracing words and actions back to their original sources, and the absence of legitimate ownership or disowning on behalf of the group all contribute to Antifa's autonomization. 102 As a result, Antifa evolves into a distinct entity, separate from its actual members and its prominent censurers.

In conclusion, a comprehensive grasp of Antifa's group status necessitates complementing sociological and collective intentionality analyses with a personification approach. Within this framework, Antifa is perceived as an externally constructed personaan entity that primarily speaks and acts through the words and actions attributed to it by 102 See, for instance, Brandy Zadrozny and Ben Collins, "Antifa Rumors Spread on Local Social Media with no Evidence," NBC News (June 2, 2020), available online at: https://www.nbcnews.com/tech/tech-news/antifarumors-spread-local-social-media-no-evidence-n1222486. reporters, exegetes, and detractors. Hence, it is imperative to recognize a notable risk of Antifa becoming autonomous.

Reflections from a personification viewpoint

In this section, I will delve into the potential insights that Antifa members could glean from this argument, drawing upon the four factors developed in section 2. This discussion aims to provide a more explicit understanding of the practical relevance and application of the intellectual framework presented.

Three reflections for insiders

Reflection 1. As mentioned earlier, Antifa activists deliberately embrace anonymity and underground operations (Factor 1) to avoid persecution and arrest. Conversely, Antifa's disposition to be externally defined and demonized (Factor 4) is an unintended by-product of its organizational structure. To counter this observation, some activists could reply that outward personification comes with a trade-off, as negative attention helps to publicize the movement's goals. Vysotsky explains that "media attention to confrontational protests and disruptive clashes… informs the culture and style of antifa activism." 103 After all, there is no such thing as bad publicity. Furthermore, Antifa members might argue that the collective has a sufficiently strong identity. This identity is established by direct actions, pledges, symbols, activism on the web, and statements by members in media interviews.

However, even if it is consciously tolerated, this exogenous definition of the group's identity undoubtedly impinges upon the internal perceptions of Antifa members, their ethos, 103 Vysotsky, American Antifa, p. 95.

and their contingent we-mode reasoning. What external actors say has a feedback effect on the group's persona and triggers new behaviors among genuine activists. Supporters must exert significant energy to debunk myths about Antifa. 104 And yet, as noted before, there is no authoritative voice capable of disavowing a statement or action on behalf of the entire collective of US antifascists. In fact, there is a structural imbalance between the ability of external definers to intentionally or unintentionally attribute false words and actions to Antifa, and the ability of a fragmented and anonymous collective to challenge them. The situation is aggravated by the mistrust shown by many militants towards the media 105 and towards non-state organizations that could act as potential allies. 106 Additionally, what actors say concerning Antifa's violence may attract new militants, who will act in accordance with the goals of the apostrophized entity. As a result, the group may start speaking and acting in ways that its members, and even its first conjurors, never contemplated. In short, Antifa runs the risk of autonomizing. If external agents become as influential as genuine members in determining what the group stands for, the cost of this worldwide publicity must be reckoned. 107 Radical left activists are not unaware of this danger, alerting to the "warping" effect of media portrayals of the movement. 108 In a nutshell, this increasing visibility comes with the potential cost of losing control over the narrative, potentially distorting the movement's essence in the public discourse. sole protagonist of the action. This phenomenon has been noted by Castells: "the rejection of leadership" means that "the network became the subject." 109 Simultaneously, the absence of visible spokespersons means that no one can disavow actions on behalf of the group or take the blame when appropriate. In the words of Raimo Tuomela, a scholar specialized in collective agency, there is no "positional power structure" where "those higher up in the hierarchy are responsible for those lower in the hierarchy." 110 Without a framework for intragroup accountability, the group as a whole absorbs the blame for its misdeeds. Nonetheless, opacity does not eliminate responsibility; it merely complicates the question of its allocation.

So, who should be held accountable?

A sensible answer would be everyone. The flipside of anonymity is that each member bears co-responsibility for the transgressions attributed to the group. When individuals choose to participate in the antifascist endeavor, they must be aware that they bear a share of blame for the actions anonymously performed in the movement's name. As Kutz would argue, no matter what their "causal contribution" is to the action, they can be seen as participating in a collective undertaking or at least in a "way of life" that may inflict "unstructured collective harms." 111 Whereas it may be the case that actions and words imputed to Antifa are endorsed by only some of its members, by accepting the movement's anonymous structure, activists become associated with each other's actions. Furthermore, if anonymity and horizontality are permanent features of the movement, the only way to distance oneself from an action is to individually and publicly opt out. Reflection 3. The absence of a clear boundary of belonging (Factor 3) presents an additional complication when we ponder the potential intervention of so-called "lone wolves" acting in the name of the group. Researchers in psychology of radicalization Sophia Moskalenko and Clark McCauley contend that "lone wolf political attacks" are often motivated by "group identification." Non-aligned individuals may "sacrifice for the welfare of a group of anonymous strangers." 112 If a reprehensible act, one that the vast majority of the group's members would not authorize, is carried out on behalf of Antifa by a lone wolf, the group would still share moral responsibility for it. Notwithstanding its decentralized character, Antifa should be considered to have a collective obligation to prevent, as a group, morally reprehensible acts. The fact that a movement lacks a defined structure of responsibilities does not erase the collective duties it may bear. 113 While Nigel Copsey and Samuel Merrill have demonstrated that several Antifa activists show "restraint" and share "the recognition that Antifa should not initiate violence," due to Antifa's current setup, no one would be in a position to disown or condemn it. 114 So, how could the group as a whole save face if the action of a lone wolf is attributed to it?

Conclusion

To conclude, I grappled with a problem prevalent in public opinion, particularly highlighted during the US 2020 presidential debate: What kind of group is Antifa, if it can even be considered a group at all? Firstly, I reviewed the main responses to the question in social 112 Sophia Moskalenko and Clark McCauley, "The Psychology of Lone-wolf Terrorism," Counselling Psychology Quarterly 24:2 (2011), p. 123. 113 According with Violetta Igneski, it can be envisaged that even "unstructured groups can have the mediated capacity to achieve a moral end and so can have collective duties and this gives individuals that are part of unstructured collectives obligations to do their part." See Violetta Igneski, "Individual Duties in Unstructured Collective Contexts," in Collectivity, Kendy Hess et al. (eds.), p. 138. 114 Nigel Copsey and Samuel Merrill, "Violence and Restraint within Antifa: A View from the United States," Perspectives on Terrorism 14:6 (2020), p. 129. studies. Then, I reconstructed the ontological assumptions that underlie the political debate surrounding Antifa. Whereas there are many plausible answers, I attempted to demonstrate that none of them fully captures an important aspect of this phenomenon: its external constitution as a collective entity. Because Antifa lacks representatives or authorized spokespersons, it speaks and acts mainly through reporters, exegetes, and detractors. Therefore, our focus should be on the attribution of words and actions, rather than on the movement's decentralized structure or the collective intentions of its members. To develop an account that meets this test, I employed four axes of analysis: attribution, performativity, personification, and autonomization. Based on this perspective, Antifa can be understood as an externally defined personification. It is mainly treated and constituted as a person by nonmembers who ascribe words and actions to it. I also claimed that this process entails the potential danger of autonomization. Even if the attribution is intentionally aimed at demonizing the movement, the personification thus created may start speaking and acting in ways not previously contemplated. Finally, I derived three insights that group members may extract from this interpretation.

With this approach, my aim is to enrich the conversation on an intriguing political issue, namely, the status of a decentralized and anonymous social movement, spanning three distinct levels: real politics, political science, and political ontology. As demonstrated, this undertaking transcends mere theoretical exploration. Research on the nature of Antifa (is it a group or not?) is not ineffectual in practical terms. An accurate characterization of Antifa's nature equips us to better discern the words and actions legitimately attributable to it. In more concrete terms, this clarification allows us to discard accusations of highly coordinated operations of terrorism associated with the movement. The novel understanding of Antifa's nature, as I posit, introduces a fresh perspective to approach genuine challenges arising from the externally imposed characteristics glued to the movement. My objective, then, extends beyond addressing the overlooked aspects within current frameworks applicable to social movements. I aspire to provide militants and democratically engaged actors with a toolkit that facilitates a lucid grasp of both the potential and the limits of collective agency.

Factor 3 .

 3 No clear boundaries of belonging: As Vysotsky summarizes, "Antifa activity is fundamentally decentralized in that it is open to anyone who identifies as an antifascist."26

  77 See Paul Chilton and George Lakoff, "Foreign Policy by Metaphor," in Language and Peace, eds. Christina Schaffner and Anita Wenden (Amsterdam: Harwood, 1995), p. 39; and Alexander Wendt "The State as Person in International Theory," Review of International Studies 30:2 (2004), pp. 289-316. 78 See Joel Bakan, The Corporation: The Pathological Pursuit of Profit and Power (New York, NY: Simon & Schuster, 2004), p. 26. 79 Mikey Biddleston et al., "Conspiracy Theories and Intergroup Relations," in Routledge Handbook of Conspiracy Theories, Michael Butter and Peter Knight (eds.), (London, UK: Routledge, 2020), p. 221. 80 Purington et al., "'Alexa is my new BFF' Social Roles, User Satisfaction, and Personification of the Amazon Echo," Proceedings of the 2017 CHI conference extended abstracts on human factors in computing systems (2017), p. 2858. 81 Achille Mbembe, Necropolitics, trans. Steven Corcoran (Durham, NC: DUP, 2019), p. 107. 82 Sheryl Hamilton, Impersonations (Toronto, CA: UTP, 2009), p. 8.

BBC News, "Antifa: Trump says group will be designated terrorist organisation," BBC (May 5, 2020) available online at: https://www.bbc.com/news/world-us-canada-52868295.

Peters and Woolley, The American Presidency Project, available online at: https://www.presidency.ucsb.edu/node/343824.

Trump, Donald (@realDonaldTrump). 2020. Twitter, October 1, 4:31 a.m. https://twitter.com/realDonaldTrump/status/1311493853615071232

Gary LaFree, "Is Antifa a Terrorist Group?," Society 55 (2018), pp. 248-49.

The Global Terrorism Database criteria are available online at: https://www.start.umd.edu/gtd/downloads/Codebook.pdf

Klein, "From Twitter to Charlottesville," p. 301.

Vysotsky, American Antifa, p. 171.

Ruth Reader, "White nationalists are Using Fake antifa Twitter Accounts to Disrupt Protests," Fast Company (June 3, 2020), available online at: https://www.fastcompany.com/90512186/white-nationalists-are-using-fakeantifa-twitter-accounts-to-disrupt-protests?

28 Available online at: https://www.adl.org/

antifa29 Cf. Kenney and Clarke, "What Antifa is;" Tina Nguyen, "How 'Antifa' Became a Trump Catch-all," Politico (2 June, 2020), available online at: https://www.politico.com/news/2020/06/02/how-antifa-became-a-trumpcatch-all-297921; Aleszu Bajak and Javier Zarracina, "How the Antifa Conspiracy Theory Traveled from the Fringe to the Floor of Congress," USA Today (January 13, 2021), available online at: https://eu.usatoday.com/indepth/news/2021/01/12/how-antifa-conspiracy-theory-traveled-fringe-floor-congress/6620908002/

This account of corporate agency is given by Kendy Hess, "The Peculiar Unity of Corporate Agents," in Collectivity: Ontology, Ethics, and Social Justice, Kendy Hess, Violetta Igneski, and Tracy Isaacs (eds.), (London: Rowman & Littlefield, 2018), p. 37.


Julie Coloigner

Ronald Phlypo

Adam Bush

Natasha Lepore

John Wood

FUNCTIONAL CONNECTIVITY ANALYSIS FOR THALASSEMIA DISEASE BASED ON A GRAPHICAL LASSO MODEL

Keywords: fMRI, Resting state, Connectivity, Thalassemia disease, Graph theory, Graphical Lasso method HHS Public Access

Thalassemia is a congenital disorder of hemoglobin synthesis which can lead to thromboembolic events and stroke in the brain. In this work we propose to use a functional connectivity model to discriminate between control and diseased subjects. Our connectivity measure is based on functional magnetic resonance imaging, and hence common variations of the blood oxygenation level in spatially distant areas. Analyzing this connectivity could highlight abnormal neuronal activation and provide us with a descriptor (bio-marker) of the disease. To estimate the connectivity, we propose a robust learning scheme based on the graphical lasso model, whose hyperparameter is validated within a cross-validation scheme. To analyze model fit, we transfer the mean connectivity from the control group to the thalassemic patient group. Our null hypothesis is that the model learned on control subjects is perfectly adequate (in the maximum likelihood sense) to describe the patients. The results of the permutation test suggest that the some patients with thalassemia do not have the same connectivity structure as the control.

INTRODUCTION

β-thalassaemia is a congenital disorder of hemoglobin synthesis that is characterized by a decreased production of globin β-chains and the subsequent accumulation of unpaired αglobin subunits [START_REF] Musallam | Cerebral infarction in β-thalassemia intermedia: breaking the silence[END_REF]. The presence of this globin precipitates also leads to increased red blood cell destruction (hemolysis), resulting in chronic anemia. The patients require regular blood transfusion and iron chelation therapy. Observational studies showed a high prevalence of thromboembolic events, which are mostly venous and their occurrence increases with age [START_REF] Musallam | Cerebral infarction in β-thalassemia intermedia: breaking the silence[END_REF][START_REF] Musallam | Brain magnetic resonance angiography in splenectomized adults with β-thalassemia intermedia[END_REF]. Its effect on the brain has not been widely studied and the incidence of strokes has only recently been established in [START_REF] Musallam | Brain magnetic resonance angiography in splenectomized adults with β-thalassemia intermedia[END_REF]. 37% of patients showed asymptomatic brain damage, which involved the subcortical white matter in all patients on magnetic resonance imaging (MRI) [START_REF] Taher | Asymptomatic brain magnetic resonance imaging abnormalities in splenectomized adults with thalassemia intermedia[END_REF].

In addition to these investigations into structural MRI, analysis of functional connectivity remains promising as a neuroimaging marker of thalassemia. Indeed, functional MRI (fMRI) studies have found that spontaneous low-frequency (0.009 ≤ f ≤ 0.08 Hz) blood oxygenation level-dependent contrast fluctuations measured during rest showed high temporal coherence between functionally related brain regions [START_REF] Fox | Clinical applications of resting state functional connectivity[END_REF]. This result suggests that fMRI might also be appropriate for examining functional connectivity. Mathematically, graph theory is employed to evaluate fMRI brain network connectivity, which models the brain as a complex network composed of nodes associated with regions of interest, and edges representing functional connectivity between nodes. Various statistical methods have been adopted to infer the latent connectivity from neuroimaging data. One of the techniques is partial correlation analysis (normalized version of the inverse covariance matrix), which provides a much better modelization of brain connectivity than simple correlation analysis. The inverse covariance matrix can be considered a faithful representation of a Gaussian graphical model. Indeed a zero entry corresponds to conditional independence of a pair of nodes, given their complement in the network. This constraint is also valid because neurological findings have demonstrated that a brain region usually only interacts directly with a few other brain regions. We will here use graphical lasso to estimate a such sparse network [START_REF] Friedman | Sparse inverse covariance estimation with the graphical lasso[END_REF]. Extension of these techniques estimate intra-subject brain connectivity model under the assumption that they have the same structure can be found in all individuals in the group [START_REF] Varoquaux | Detection of brain functionalconnectivity difference in post-stroke patients using group-level covariance modeling[END_REF][START_REF] Phlypo | Deriving a multi-subject functionalconnectivity atlas to inform connectome estimation[END_REF][START_REF] Ng | A novel sparse group gaussian graphical model for functional connectivity estimation[END_REF]. It has proven sensitive to correctly detect existing connections in a graph structure under some mild assumptions. Different patterns of brain connectivity have been shown in Alzheimer's disease [START_REF] Huang | Learning brain connectivity of alzheimer's disease by sparse inverse covariance estimation[END_REF].

In this paper, starting from a correlation metric, a robust learning scheme is proposed based on a graphical Lasso model whose hyperparameter is fixed within a crossvalidation scheme, in order to estimate a descriptor of reference brain activation. Thalassemia patients could be affected by strokes, altering some connectivity patterns. Given this variability of the damage and the abnormal blood flow in thalassemia, we hypothesize that at least for some patient's abnormalities in connectivity patterns exist in patients as compared to control subjects. Based on the Gaussian likelihood model, a network cross-validated on control subjects is individually verified on thalassemia patient data. Our null hypothesis is that such a model learned on control subjects is perfectly adequate to describe patients. Permutation tests are used to assess the p-value of every patient. The statistical method is tested on a cohort of 20 control subjects and 11 thalassemia patients.

MATERIALS

Dataset

This study includes thalassemia patients and control subjects that were recruited from the Children's Hospital Los Angeles between January 2012 and September 2015. The institutional review board approved the protocol and written informed consent was obtained from all subjects. All participants underwent MR imaging by using a 3T Philips Achieva. The 3D T1-weighted images were acquired covering the whole brain (160 sagittal slices) with TR = 8.20 s, TE = 3.77 ms, flip angle = 8, in-plane resolution = 256 × 256, FOV = 256 mm × 224 mm and thickness/gap =1.0/0 mm). During resting-state fMRI scanning, subjects were instructed to close their eyes, keep still as much as possible, not to think of anything, and not to fall asleep. The functional images were acquired with the following parameters: TR = 2000 ms, TE = 50 ms, flip angle = 90, in-plane resolution = 96 × 96, FOV = 220 mm × 220 mm, 26 axial slices, thickness/gap= 5/0 mm. A total of 240 volumes were collected in 8 minutes. At this stage of the experiment, the population sample consists of 11 patients with thalassemia and 20 control volunteers, but data acquisition is ongoing.

Preprocessing steps

Imaging data was first preprocessed with the FMRIB Software Library (FSL), using standard spatial preprocessing steps: images were (1) slice-time corrected, (2) realigned to remove physiological motion with FSL's MCFLIRT, (3) intensity normalized and ( 4) smoothed with a 6-mm Gaussian kernel. The fMRI images were co-registered with their anatomical counterpart using FSL and linearly transformed to the Montreal Neurological Institute (MNI) template space. After fMRI preprocessing, in order to remove residual motion, the parameters estimated by FSL's MCFLIRT, as well as theirs derivatives, were used as regressors, computed by backwards differences (12 regressors). Moreover, the physiological noise was also reduced using other nuisance regressors that were calculated by the CompCor [START_REF] Behzadi | A component based noise correction method (compcor) for bold and perfusion based fmri[END_REF] method as implemented in Nilearn (http://nilearn.github.io/). These 5 regressors correspond to the principal components from noisy regions-of-non-interest, such as white matter, cerebral spinal fluid and out-of brain.

Regions of interest selection

In order to analyze functional connectivity, the resting state data was parcellated into 39 regions using the multi-subject probabilistic atlas from [START_REF] Varoquaux | Multi-subject dictionary learning to segment an atlas of brain spontaneous activity[END_REF]. It has been shown to provide good support to define regions of interest in fMRI studies, and it is known that the the choice of the regions of interest (ROI) that define the nodes of the graphs has a great influence on the assessment of the connectomes. Regional mean time-series are estimated by averaging the fMRI signals over all voxels within each atlas region. From these regional mean timeseries, we can compute the empirical correlation matrix, denoted S (k) , for each participant. We also show an example of this matrix used for learning the model, as described in Figure 1. Note that it displays features with high connectivity in the upper left part, corresponding to the default mode network.

METHOD

In this section, we present a robust learning scheme, through which we estimate a descriptor of the reference functional connectivity structure. A sparse modeling framework is employed based on a graphical Lasso model associated with a cross-validation scheme. Then, based on the Gaussian likelihood model, a mean network estimated with control subjects is applied to the thalassemia patient data. Permutation tests are used to assess the sensitivity and specificity of our model.

Learning model

Starting from a training set of K control subjects, the graphical Lasso model is represented through a precision matrix, Θ, corresponding to the inverse correlation matrix, Θ = S -1 . We assume that the variables have a multivariate Gaussian distribution with covariance S. If the edge linking nodes j and i is absent, then nodes j and i are conditionally independent given all others, and the corresponding entry of the inverse covariance matrix, Θ, is zero.

The estimation of Θ is based on 3 steps: i) the set of precision matrices {Θ (1) , ⋯, Θ (K-1) } conditional on a value λ are first estimated. ii) λ is fixed through a 10-fold crossvalidation (each subset of K -1 controls are validated on 1 control with K = 10) iii) The model is tested on the K-th subject by calculating the likelihood of the patient data in the model with parameter Θ, the mean precision.

For step i), to estimate a sparse symmetric positive definite parameter, Θ (K) , we maximize the penalized Gaussian log-likelihood, for all K -1 subjects [START_REF] Friston | Functional connectivity: the principalcomponent analysis of large (pet) data sets[END_REF]:

Θ (k) = arg min Θ (k) > 0 Trace(Θ (k) S (k) ) -logdet(Θ (k) ) + λ‖Θ (k) ‖ 1 (1)
over a grid of values for the penalization parameter λ and where S (k) is the covariance matrix of the k-th subject. Note that log det and Trace correspond to the logarithm of the determinant and the trace of the matrix, respectively. The operator || || 1 is the l 1 -norm matrix.

The parameter λ is a penalty parameter, which controls the amount of sparsity. The blockcoordinate descent optimization algorithm proposed by Friedman et al. [START_REF] Friedman | Sparse inverse covariance estimation with the graphical lasso[END_REF] is used, which ensures the symmetric positive definiteness of the estimate Θ (K) , during the optimization procedure.

Cross-validation

To train the model, a leave-one-out cross-validation scheme is used. A subject is extracted from the training set as a validation subject, and the model is trained (i.e. estimate the model parameter λ is estimated) with the remaining K -1 participants. This is repeated such that each control subject is used as a validation sample. We report the optimal parameter λ, that maximizes the mean log-likelihood over all K-folds.

Using this optimal λ for every subject k, the precision matrix, Θ k is estimated again. From {Θ 1 , ⋯, Θ K-1 }, the Frechet mean is used to estimate the reference connectivity model, Θ [START_REF] Varoquaux | Detection of brain functionalconnectivity difference in post-stroke patients using group-level covariance modeling[END_REF].

Permutation test

The model determined above to estimate healthy brain activation is applied to the Q data of thalassemia patients. Our null hypothesis (H0) is that the model learned on control subjects is perfectly adequate (in the maximum likelihood sense) to describe the patients. For each of the patients (with labels q = 1, …, Q), the log-likelihood in a Gaussian distribution with mean 0 and the covariance Θ is calculated. We permute the data by shuffling the subjects' labels (control or patient), and then calculate the same log-likelihood statistics for every permutation. Finally, the statistical significance, expressed in terms of a p-value, is calculated as the fraction of likelihood that is at least as high as the original (non-permuted) statistic, which was derived from the correctly labeled data.

RESULTS

First, the healthy brain functional connectivity structure was estimated from the 12 control subjects. A grid value of λ from 0 to 1 was used and a leave-one-out scheme was repeated K = 12 times. Figure 2 displays the inverse correlation model, giving a descriptor of reference activation, obtained by the learning scheme. Compared to the covariance matrix of a subject, displayed in Figure 1, we observe that the precision matrix is more sparse, as expected. Indeed, only direct connections between two ROIs are represented in the inverse covariance matrix. In addition, graphical representation of the connection for the atlas-based ROIs are shown in Figure 3. It displays the highest scores related to the homologous interhemispheric connections; in other words, each region tends to be highly correlated with the corresponding region in the opposite hemisphere. The sagittal view of the Figure 3 shows the connections between the medial prefrontal cortex and the precuneus, implicated in well known networks such as the default mode network.

Then, the model estimated previously is applied to the Q = 11 thalassemia patient data. Our null hypothesis is that such a model learned on control subjects is perfectly adequate (in the maximum likelihood sense) to describe thalassemia patients. Three patients had a p-value inferior to 5%, leading to the conclusion that H0 is rejected. The results of the permutation test suggest that the some patients with thalassemia do not have the same connectivity structure as the controls. Higher p-values (p-value>0.1) were observed for 7 patients, which means that the likelihood of these data in the model do not allow to reject H0. Our classification results were compared with the one obtained by a correlation matrix. The pvalues of all subjects are high. This model seems not to show differences between the patients. Significant correlation was found between p-values and global CBF estimations.

CONCLUSION

In this paper, we proposed a robust learning scheme based on a graphical Lasso model to estimate the reference brain functional connectivity structure. Based on a permutation test, we showed that the model learned on control subjects is not adequate to describe several thalassemia patients. The results of the permutation test suggest that three thalassemia patients do not have the same connectivity structure as compared to reference subjects. Indeed, the strokes and abnormal blood flow in thalassemia patients can affect brain activation patterns. This method may help to identify the patients at greatest risk for cerebral strokes and for neurocongitive dysfunctions. This study will provide insight into risk factors for cerebrovascular disease in SCD patients, which will facilitate improved neuroprotection and quality of life. Future works will consider the inclusion of individual's clinical variables, such as stroke, hemoglobin levels and neurocognitive functioning and will explore their impact on the connectivity patterns. Finally, this is an ongoing study, and we plan to pursue it on a larger database. Connectivity matrix from the 39 regions: each coefficient in the matrix represents the correlation coefficient between two ROIs [START_REF] Phlypo | Deriving a multi-subject functionalconnectivity atlas to inform connectome estimation[END_REF]. Inverse correlation model, giving a descriptor of reference brain activation, computed by the procedure described in sections 3.1 and 3.2. Graphical representation of the reference connectivity model.

Fig. 1 .

 1 Fig. 1.

Fig. 2 .

 2 Fig. 2.

Fig. 3 .

 3 Fig. 3.

Proc IEEE Int Symp Biomed Imaging. Author manuscript; available in PMC 2018 October 17.