Migration from a Dialectical and Historical Materialist perspective

The large and growing contingent of migrants in the world today who move in different directions, occupying a peripheral place in terms of space, occupation, education and access to public services, leads us to problematize analyses about the phenomenon of migration. In this direction, we present some theoretical supports for research about this theme. The objective is to contribute with analyses that seek to go beyond appearances and capture the multiple determinations of the concrete, that is, to understand the reality that moves workers and their families to migrate. We understand that migratory movements accompany the process of capital expansion in the direction of accumulation, given that capitalist accumulation produces a population of surplus labor, according to Marx, which is available to be sent in different locations and production sectors. We conclude that the category of migration a historical materialist perspective is a phenomenon that originates in the expropriation of the means of subsistence and the exploitation of labor, and therefore, cannot be understood outside of these processes. In this perspective, we use the categories of accumulation, commodity, industrial reserve army and spatial expansion of capital to analyze the movement of workers.


Introduction
Massive numbers of people are in movement in the world today, whether as international or domestic migrants, or as refugees.United Nations (UN) data reveal that the number of migrants in the world increased 41% in the past 15 years.In 2015, there were an estimated 244 million international migrants, equivalent to 3.3% of the global population.(UNITED NATIONS, 2016) In terms of refugees, the United Nations High Commissioner for Refugees (UNHCR), reports that movement forced by wars, violence and persecution around the world in 2016 reached the highest number of people ever recorded.Some 65.6 million people (1 of every 113 people in the world) were forced to leave their places of origin because of different types of conflicts, 300,000 more than in the previous year.(UNITED NATIONS HIGH COMMISSIONER FOR REFUGEES, 2017).
Domestic migrations are more difficult to quantify.The United Nations estimates that there are 740 million domestic migrants in the world (KING, 2010).In Brazil, from 2005 to 2010, there were 5,018,898 domestic migrants (INSTITUTO BRASILEIRO DE GEOGRAFIA E ESTATÍSTICA, 2010).That is 30.6 migrants for every 1,000 residents.
Even if the rise in migration in recent years reveals the contradictions and permanent crisis in which capital is situated, migration is not a new phenomenon, it is a recurrent problem in the history of humanity.We consider humans as historic and social beings who produce their life by means of work in relation to nature, meeting their needs and creating new ones.To do so they mobilize tools, skills and knowledge according to the mode of production of each historic period.Mobility is present in this constitutive process of humans.This is to say that humans not only adapt to the environment by fulfilling genetic determinations, but modify it and modify themselves in this process, permanently creating means of work in different spaces and in various forms.This is to say that social beings are universalized.
We return briefly to the nineteenth century in Europe and to the process of urbanization and capitalist industrialization, which was preceded by the expropriation of land and the means of production of subsistence, and was essential to the constitution of free workers willing to sell their labor power in nascent industry and integrate the industrial reserve army in cities, sending large masses of rural workers to cities.
In the second half of the century, immense contingents of people sought opportunities for life and work in other continents, particularly the Americas.The international migration of millions of people shifted the focus of the large crisis in European counties in the nineteenth century.The population shift, created a powerful survival mechanism for capitalist accumulation.A movement in an opposite direction is observed in the late twentieth and early twenty-first century, when thousands of workers and their families migrated in search of work and political exile, given that civil wars and dictatorship had dominated Latin America.Many Brazilians, for example, sought the central regions of capitalism, which fed an enormous industrial reserve army.The migrants submitted themselves to low salaries, long work shifts and simple occupations that required little training and had low social prestige.In this way, the migrations became an important component of urbanization and capital accumulation.
In the particular case of Brazil, there was intense domestic migration in the early twentieth century, when workers left the fields for industrializing regions.In the 1960's, the exodus of rural areas intensified, in the context of the so-called green revolution, which imposed a new productive standard for agriculture, based on mono-crops and dependent on agricultural machinery and chemical inputs produced and sold by foreign companies.Small farmers were unable to continue to produce their life in the rural areas, many lost their land due to debt.Thus, part of the population moved to the cities, forming a mass of workers available to capital, with this being an example of the contemporary symbiosis between expropriation of land and expanded exploitation of labor.
With the imposition of a dependent and subordinated development model for Brazil, and with a constant readjustment of interests between the bourgeois class and old oligarchic sectors, and of both with international capital, a fragile internal market was established and regional and social inequalities were heightened, which provoked a great shift of the population between regions of the country.Paul Singer (1973) affirmed that regional inequalities were a central motor of domestic migrations in the process of capitalist industrialization.
Nevertheless, we understand that the regional disparities cannot be explained by a dualistic vision that opposes the backwards to the modern or the developed to the under-developed.This vision is very common for explaining migrations from Brazil's Northeast to Southeast for example.Oliveira (2003), criticizing this dualistic vision, indicates that in Brazil, modern industry was fed by an outdated subsistence economy."Outdated agriculture financed modern agriculture and industrialization" (OLIVEIRA, 2003, p. 129), by both lowering the cost of urban labor power and promoting a surplus of labor.In this way, he maintains, "underdevelopment was not exactly a truncated evolution, but the production of dependency by the conjunction of place in the capitalist international division of labor and the articulation of domestic interests".(OLIVEIRA, 2003, p. 127).Thus, "underdevelopment would come to be, therefore, the form of permanent exception of the capitalist system in its periphery".(OLIVEIRA, 2003, p. 131).
In this context, this article will conduct a historic and dialectical analysis of the migratory process, seeking to overcome dualities between rural and urban, center and periphery, north and south, outdated and modern, origin and destination.The challenge that is raised is to go beyond appearances and capture the multiple determinations of the concrete, according to the analysis of Marx (1982b), that is, to understand the social processes that produce migration.We use as references classic and contemporary authors, as well as statistical data about migration.The article has two sections, the first problematizes the category of migration using new theoretical conceptualizations and the second affirms a critical analysis of migration based on classic Marxist authors.

The affirmation of migration as a central category
The current context of reduction of living labor, accompanied by increased unemployment, and informal, flexible, temporary and precarious jobs without labor contracts, has provoked greater mobility of workers between sectors of production and workplaces.In this context, the ideology of individuals as entrepreneurs of the self gains strength, they must stand out, earn diplomas, have health insurance, retirement plans, and a car or motorcycle to have the ability to compete with other entrepreneurs of the self.And all on their own merit, thanks to their effort and talent.These are workers who will not imply a cost, the state and the company are no longer responsible for them.
Moreover, these workers are willing to leave their families, homes, friends and native city to sell their labor power wherever they look.They thus become totally available to the labor market.There is an additional aggravating factor, given that they no long find a safe place to settle, and must move more frequently, which requires their detachment and adaptability, that is, they must have the ability to submit to the new.According to Kuenzer (2016), a flexible subjectivity is required of these workers, from a cognitive, behavioral and ethical perspective.
To capture this reality (which some authors consider an instantaneous moment) post-modern explanations appear.According to Kuenzer (2016), they focus on pragmatism, in which practice is considered as activity devoid of a theoretical character; on presentism -historic experience is substituted by the experience of the moment and reduced to an individual plane; and on fragmentation and dispersal in which the local fragment gains its own life and the micro becomes independent, giving an absolute quality to a particular situation of history.
The explanatory concept of the mode of production passes to a micro report as something independent, making it difficult to give foundation to an explanation and at the same time an opposition to the capitalist system as a whole.In this direction, the historic-structural interpretations about the problematic of migration are questioned under the allegation that they are not able to explain the new migratory phenomena.
King (2010, p. 13) presents a simple conceptualization of migration, "people move from one place or country to another and remain there enough time to be considered migrants".But behind an apparent simplicity, the author calls attention to the enormous complexity and variety, in terms of spatial standards, evolution through time, forms and types of movements, causes and consequences.
King also presents large explanatory historic narratives of migration.One is the ecological narrative, in which people move in search of food, cultivatable land, pasture, water and other basic resources.There is also a pioneer narrative, in which new lands maintain a promise of liberty to expand and prosper.The third narrative King presents is Marxist, which associates migration to exploitation, enslavement and labor contracts.There is also a diaspora narrative of exile and displacement from lands of origin.In this article, we will work with the Marxist explanation, considering the problematic of migration associated to labor (KING, 2010).
The study by Menezes (2012) points to reconfigurations of migrations in terms of origin, destination, duration and groups who migrate, which requires a revision of theoretical perspectives and new typologies.Based on Brito (2009), Silva and Menezes (2007) and Almeida and Baeninger (2011), Menezes identifies new characteristics of migratory processes.
In an effort to account for the heterogeneity of migrants, the intensity of migratory processes, the differentiations of flows, spaces and other factors, and considering that the forms of mobility are diffused in spaces and in time, Menezes points to concepts that have been proposed in recent studies of migration, such as: migratory trajectories, migratory field and spaces, circulatory territory and mobility, as methodological tools for understanding the character of mobility of contemporary migrations.Menezes (2012) affirms that since the 1980s in Brazil, the multiple migrations question the notion of origin and destination.Based on Martine (1982) and Brito (2009) and on her own studies, she observes that settlement and social mobility are no longer possible by means of migration.Menezes highlights the case of seasonal and temporary migrants, whose life trajectories are marked by mobility.At the same time, she obser-ves the idea of fixation, given that although migrants are in mobility, they have a locality of reference, to which they have ties of belonging.The condition of mobility does not express a lack of enrootedness, but a permanent recomposition and resignification of their networks of social relations (MENEZES, 2012).In addition to the migratory modalities, Menezes' studies reveal a varied duration and various family arrangements, as well as a greater fragility in the condition of migrant workers.Baeninger (2012) proposes the concept of migratory rotativity, considering empiric evidence about domestic migrations in Brazil that have lead, according to Baeninger, to new perspectives for their interpretation and description, and raise new conceptual challenges.
In this context, the complexity of understanding domestic migrations in 21 st century Brazilian society becomes increasingly evident.To find theoretical-methodological paths for the new reading of domestic migrations in Brazil requires considering that to be able to conceptualize migratory rotativity, it is important to highlight that we are facing a new society: which is reflexive (GIDDENS, 1991), presents risks (BECK, 1992), and is based on information technology (CASTELLS, 1999).Thus, in the case of understanding such diffuse spaces of 'departure and arrival' it is essential to consider the articulation of local processes to the regional and global realm that promote 'disembedding mechanisms' of society (GIDDENS, 1991), which have reflexes in the processes of urbanization and spatial redistribution of the population in the various regional contexts.(BAENINGER, 2012, p. 96).
According to the author, the intensification of migratory rotativity in various regions of Brazil indicates the fluidity of the labor force in the shared spaces of risk society, requiring a rereading of the concept of the mobile labor force that can be contemplated as a dimension of current domestic urban migrations, in an economy based on services, with "fluidity of the migratory movements in the current process of urbanization as well".(BAENINGER, 2012, p. 95).
Given the difficulty of distinguishing temporary migration from definitive migration, Almeida and Baeninger defend the need to study the spaces where individuals circulate and situate them in families or in their network of social relations.These authors propose the concept of migratory field and space, to "recompose the spaces traveled and organized by the relatively stable and regular set of flows of migrants, regardless of the origin or destination".(ALMEIDA; BAENINGER, 2011, p. 12).
Almeida and Baeninger even question the place of residence of individuals, which "depends on a subjective perception, a sense of belonging and spatial appropriation, and 'their' place of residence does not always coincide with the geographic space in which they live".(ALMEIDA; BAENINGER, 2011, p. 10).
What we observe in the analysis of these authors is that reality is transformed into pure image and representation, separated from the materiality of social life.What predominates is the narrative.There is no doubt that subjects attribute meanings to the place where they live, meanings in large part either ideologically tainted or by a nostalgia particular to a dramatic situation of the life that led people to its denial.Nevertheless, in the plane of theoretical analysis, we must go beyond appearance and understand the fetishistic forms that freeze and crystalize reality, which is defined discursively or ideologically.
Another element that composes the analyses proposed for migration concerns a shift of focus to the migratory subjects, emphasizing how they subjectively treat their life experiences in distinct spaces and time.In the text O voo das andorinhas: migrações temporárias no Brasil [The Flight of the Swallows, Temporary Migrations in Brazil], José de Souza Martins proposes a concept of temporary migrants that emphasizes the subjective dimension of the sense of absence.
If in demographic terms, the duration -temporary -is essential for the study of temporary migrations, in sociological terms what is essential is the concept of absence.In reality, migrants are temporary who consider themselves to be 'away from home', 'out of place', absent, even when, in demographic terms, they have definitively migrated.It is that [migrant] who considers herself to be out of place, outside 'her' social relations, and that, at the limit, does not feel herself to be part of where she is, even when she is.If absence is the core of the consciousness of temporary migrants, it is because they have not fulfilled and not completed the migration process, with its two extreme and exclusionary moments; the de-socialization from the social relations of origin, and the re-socialization in the social relations of 'adoption'.He thus remains in the duplicity of two socializations, of two structures of differing social relations.He lives the marginality of two social situations.He is always the other, the object, and not the subject.Always the one who will return to be and not what he is.The delay in this re-encounter defines temporary migration.(MARTINS, 1986, p. 49).
Martins identifies important elements for understanding temporary migrations with a focus on migrant subjects.We understand, however, based on Marxism, that the subject is collectively constituted (incorporating multiple individualities and group identities).Therefore, it involves the whole of the working class, which is exploited, expropriated and migrant, which is constituted from its class condition and identity.We are not able to separate the objective from the subjective dimension, or the economic sphere and human subjectivity, to use terms raised by Thompson (1981).We observe that for structuralism, structures determine individualities and for post-structuralism the immediate actions of individuals are the sole foundational moment of the social being.
Lara Flores, a Mexican researcher, understands that migration has become a phenomenon of mobility: "among the most important changes of the modern era is the fact that migration has become a phenomenon of mobility".(LARA FLORES, 2010, p. 7, our translation) 1 .In her book Migraciones de trabajo y movilidad territorial [Labor Migrations and territorial mobility], she seeks to illustrate the distinct dimensions of mobility and show how they refer to spatial and temporal hierarchies.
We are interested in accounting for the organization not only of those who move from one place (origin) to another (destination) but also of those who are capable of circulating, of covering spaces and appropriating them 'producing territories', participating in the creation of wealth and of new social identities.(LARA FLORES, 2010, p. 7, our translation) 2 .
We note that Flores' analysis focuses on the capacity of migrants to circulate and construct and appropriate spaces, associating the notion of migration to that of mobility and circularity.
Her study, like those of other researchers about the problematic of migration, makes an important effort to understand new aspects of migratory processes, seeking to construct new explanatory categories.According to Brito (2009), for example, the paradigm and theories related to economic development are not completely satisfactory for explaining migrations and require a profound review.I believe that the problem lies in proposing new categories in opposition to old categories that still have explanatory potential and especially the questioning of historic analyses that seek to capture reality in its particularity and universality, not by grasping particular phenomenon, which leads to fragmentation.Meanwhile, I agree that there is a need for new methodological procedures that can grasp the accelerated and increasingly more dynamic migratory flow or what, for example, Silva (1992, p. 166) denominates "permanent temporary migration", or "temporary permanent migrants".
There is no doubt that the data about reality reveal changes in migratory patterns.Nevertheless, we understand that the dualities between origin and destination, rural and urban, center and periphery, temporary and permanent can be overcome by turning to the dialectic of historical materialism.
Thus, we do not need other concepts (such as migratory field and space, circulatory territory or phenomenon of mobility), because the very category of migration itself, understood in the context of the capitalist mode of production that has as its base the exploitation of the worker for the production of surplus value, allows us to analyze the reality of the migratory movement beyond its appearance and in its totality.
We understand that the dichotomization or fragmentation of reality makes unviable an analysis of the totality that allows understanding social relations or the historic process that moves people to migrate, whether domestically or internationally, as temporary or permanent workers, skilled or unskilled.

A critical analysis of migration
As announced in the introduction of this article, migration does not constitute a current phenomenon, although it has been gaining greater volume and presents different characteristics, in terms of spatial standards, causes and consequences, forms and types of movements, and in its length and the groups who migrate.We intend to grasp, at first, the essence of the movement that generates the need for migration, that is, the forces that move capital in the direction of its increased valorization through the extraction of surplus value and that produce immense contingents of workers, who are completely available for capital.
Labor force migration accompanies the very process of expansion of capital in the direction of accumulation, given that capitalist accumulation produces a superfluous working population available to be sent to different locations and production sectors.In other words, the expropriation and development of machinery, which is intrinsic to the process of capitalist accumulation, produces a growing group of unemployed or underemployed workers that is available to move anywhere where jobs are promised and which is disposed to work in any production sector.Moreover, this international reserve army or the army of surplus workers drives down the salaries of employed workers.
In the chapter, The General Law of Capitalist Accumulation, in Capital, Marx (2008b) examines the influence that the increase of capital has on the working class.He understands that the process of accumulation increases, together with capital, the quantity of salaried workers who transform their labor power into the increasing valorization of capital.Nevertheless, in contrast to the idea that a growth in capital signifies a rise of workers, Marx (2008b, p. 733) will show that capitalist accumulation "always produces, and in the proportion of its energy and extension, a relatively superfluous working population, that is, that goes beyond the average needs of the expansion of capital, thus becoming surplus".
Marx understands that the surplus working population is a product of and simultaneously a leverage for capitalist accumulation and constitutes the available industrial reserve army, which belongs to capital in an absolute manner as if it was created and maintained by it.It provides the human material to serve the variable needs of the expansion of capital and is always ready to be exploited, regardless of the limits of the true increase of the population.(MARX, 2008b, p. 735).
Marx refers to the portion of capital (variable) that is converted into labor power, changing its value in the production process, within the composition of capital (constant and variable), determined by the relationship between the mass of the means of production employed and the quantity of work necessary for them to be employed.For this reason, labor power must continuously incorporate itself to capital, in order to expand it."For this reason, the working population, by producing the accumulation of capital, produces, in growing proportions, the means that make it a relatively superfluous population."(MARX, 2008b, p. 734).This is to say that the growth in variable capital, according to Marx, is an indicator of surplus labor, but not of more employed workers.
How is this achieved?Because the part of the working class that is employed, performs excessive labor, it is submit to extenuating work shifts and to an intensification of labor, compelled by the pressure of the reserve army, which regulates salaries.Crary (2014, p. 20), in his provocative work 24/7 -Late Capitalism and the Ends of Sleep, examines the voracity of capitalism in its efforts to reduce the time of sleep, given that "no value can be extracted from sleep".
According to Cray, recent studies show that the number of people who wake up one or more times at night to check messages or information is growing exponentially.He refers to the sleep mode, which "goes beyond the logic of off-on, so that nothing is essentially 'off' and there is never a real state of rest".(CRARY, 2014, p. 23).What is essentially presented is the idea of working without stopping, without limits, in an instantaneous availability, or as Crary affirms (2014, p. 39), "24/7 announces a time without time".
This instantaneous availability refers to the extrapolation of time and space, which leads workers to make themselves available at any time, at any place, for whatever productive sector, contract, salary, working conditions and requirements, and regardless of the language and culture of the new working and living place.
The historic condition for this process is in what Marx (2008a) calls primitive accumulation, or in the historic process that dissociates workers from the means of production, The first requirement of capitalism was the dissolution of the relationship with the land, through the usurpation/enclosure of common lands and expulsion of the peasants, making the agricultural population available for industry and rural land available for capitalist agriculture."The last great process of expropriation of the peasants is finally the so-called cleansing of properties, which consists in sweeping away these humans."(MARX, 2008a, p. 842).Thus, the history of primitive accumulation is constituted by movements of large masses of humans who are violently denied their means of subsistence and launched into the labor market."The renovated, uninterrupted, intermittent expropriation and expulsion of the rural population, provides urban industry always new masses of proletarians completely disconnected from the corporate sphere."(MARX, 2008a, p. 858).
This process is not limited to the genesis of the capitalist mode of production, it is a condition of capitalist accumulation, which causes the processes of expropriation and expulsion to continue and even intensify in the context of capitalist crisis, increasingly freeing workers from the means of subsistence and labor and continuously producing a relative surplus population that maintains the law of supply and demand of labor.The expropriations constitute, according to Fontes (2012), a permanent process, a condition of constitution of the capitalist social base and that is deepened and generalizes with capitalist expansion.
Fontes (2012), in her book Brasil e o capital imperialismo [Brazil and Capital Imperialism], addresses the current forms of expropriation by challenging us to understand the specific forms of contemporary capitalism and imperialism, particularly the role performed by Brazil.Fontes affirms that the expansion of capital provokes the concentration of social resources and the permanent recreation of social expropriations.Whether the expropriations are primary (original, as Marx referred to and mentioned above in the so-called primitive accumulation of capital) or secondary expropriations, driven by contemporary capital-imperialism.
Secondary accumulation, according to Fontes (2012, p. 54), constitutes a "new -and fundamental -form of exasperation of the availability of workers for the market, imposing new conditions and opening new sectors for the extraction of surplus-value".This process is revealed, according to the author, in the dismantling of social and labor rights, in the privatization of public companies, in contractual expropriation, in expropriation of strategic raw materials, knowledge, biodiversity, various technologies, in the expropriation of collective goods and others.As a result, she points to the "unimaginable commodification of all forms of social and human life".(FONTES, 2012, p. 59).
In terms of the problematic of this article in particular, the expropriation can be seen in the supply of a mass of workers available for international exploitation and forced to give up the historic conquests of the working class.To do so, they move through different sectors, no longer counting on specialized education, which is substituted by flexible learning, in which adaptability and the ability to submit to the new is more important than having previous qualifications (KUENZER, 2016).They also move through different locations, from the field to the city, from one city or state to another, or even outside a country.They are migrant workers who, given their condition as foreigners, are submitted to simple and precarious low-skilled jobs, which are poorly paid and have long shifts, often in more than one job.They regularly work more than eight hours a day without a labor contract, 13 th month salary, transportation benefits, weekly rest or annual vacation.They also do not have an opportunity to exercise political rights, such as participating in public demonstrations or joining unions or other political organizations.In the case of women, they assume most of the responsibility for domestic work, childcare and must deal with the permanent sexual harassment of colleagues, bosses and the police.In the case of youth, when they are able, they try to associate work to study.Thus, migrants form a mass segregated behind walls, in ghettos or distant neighborhoods, constituting the most fragile and vulnerable workers who reinforce the general subordination of the working class.
Sáskia Sassen (2016) proposes the category of expulsions to explain the current socio-economic and environmental movements.She observes the rise of new logics of expulsion with the growing number of people, companies and places expelled from central economic and social orders.According to Sassen, "primitive accumulation is executed by means of complex operations and by very specialized innovation, which ranges from the logistics of outsourcing to the algorithms of finance".(SASSEN, 2016, p. 21)  3 .Among the aggravated cases of expulsions, she points to the growing dislocated population and the rapid increase in the incarcerated population.
For Sassen, the end of the Cold War triggered one of the most brutal economic phases of the modern era, in which capitalism reorganized in a radical form, seeking expanded modes of extraction of profits.Two logics permeate this re-organization: One is systematic and is inserted in the economic policies and those for (de)regulation of the majority of countries, of which the most important are privatization and the elimination of import tariffs.[…] The second logic is the transformation of increasing areas of the world into extreme zones for these new or much greater modes of extraction of profits.The best known are the global cities and spaces for outsourced labor.(SASSEN, 2016, p. 28).
Sassen reveals how these logics provoke an extreme process of expulsions from life projects and means for survival, from a belonging to society.
What is grasped from the forms of expropriations and expulsions is that they are not the exception, but the rule of the concentrating and expansionist logic of capital.It is the very concrete form of the existence of capital focused on the extraction of surplus value, which is based on the existence of free workers, expropriated from the means of production and available for capital, thanks to the transformation of labor power into commodities.
Labor power, which is a special commodity 4 to the degree that it preserves and increases the value of other commodities, is initially presented in the labor market within the logic of supply and demand.Given the growing mass of available workers, the high rates of unemployment and the reserve army, to be realized it must be presented where there is demand, which often means being uprooted from its place of origin, that is, migration to different locations, in increasingly insecure and precarious conditions, constituting "permanently temporary workers", in the terms of Silva (1992, p. 166).
Beverly Silver (2005), in her study about workers movements and globalization since 1870, observes the successive shift of production as a solution of capital, which only postpones crises.The recurring standard of industrial expansion followed by the rise of strong workers movements led to one of the main theses of her book: wherever capital goes, conflict follows 5 .This is explained because labor dissatisfaction towards the processes of capital accumulation on a global scale is related to the contradictions that are part of the transformation of labor into commodity.
Considering that the transformation of labor into a commodity generates labor dissatisfaction towards the processes of capital accumulation on a global scale, Silver (2005) analyzes spatial shifts as one of the responses of capital to the rise of strong labor movements 6 .The spatial dynamic of capital signifies the process of differentiation between geographic areas in relation to the level and intensity of the commoditization of labor.Thus, in some periods and locations, concessions can be observed to a small portion of the working class.
Based on Silver's studies, we can observe that the movement of workers is related to spatial shifts of capital in a pattern of continuous recreation of contradictions between labor and capital.
The thesis that David Harvey has been developing in his studies about the unequal geographic development of capitalist accumulation helps us to understand in greater depth the spatial movements of capital and labor, by emphasizing the importance of the capacity to move in space, commodities, productive capacity, people and money.In his work, The New Imperialism, Harvey observes "an incessant impulse of reduction, if not elimination of spatial barriers, associated to equally incessant impulses of acceleration of the rate of circulation of capital".(HARVEY, 2014, p. 86).According to Harvey, the basic idea of a temporal, spatial order 7 is simple: Overaccumulation in a given territorial system represents a condition of surpluses of labor (higher unemployment) and surpluses of capital (registered as an accumulation of goods in the market that cannot be realized without a loss, as idle production capacity and or as surpluses of monetary capital that lack productive and profitable investment opportunities).These surpluses can be potentially absorbed by the following factors: (a) a temporal shift through investments in long term capital projects or social spending (such as education and research), which delay the future re-entrance in circulation of capital assets; (b) spatial shifts through the opening of new markets, new productive capacities and new possibilities for social and labor resources, in other places; or (c) some combination of (a) and (b).(HARVEY, 2014, p. 93).
Harvey shows capital's need to continuously expand through predatory practices of primitive accumulation, thanks to the key role of the policy of territorialization of the state and its imperialist practices, which orchestrate institutional arrangements to preserve the standard of asymmetries more advantageous to the dominant capitalist interests.In this direction, new mechanisms of accumulation through plunder are observed.He mentions intellectual property rights, bio-pirating, the destruction of global environmental resources, the transformation into commodities of cultural and historic forms and of intellectual creativity, the corporatization and privatization of goods until now public (such as universities), the new wave of "expropriation of common lands", and others (HARVEY, 2014, p. 123).
The author reveals how accumulation through plundering helps to resolve the problem of surplus accumulation of capital.
Overaccumulation, we recall, is a condition in which surpluses of capital (at times accompanied by surpluses of labor) are idle without sight of profitable outlets.The key term here is, however, capital surpluses.What accumulation by plundering does is to liberate the group of assets (including labor power) at a much lower cost (and in some cases, zero).The over accumulated capital can take possession of these assets and immediately put them to profitable use.(HARVEY, 2014, p. 124).
In this way, we observe an accelerated process of privatization of a broad portion of goods that until then were public, including material and immaterial goods, land and natural resources together with symbolic and cultural goods, educational and welfare-related, as forms of resolving the problem of over accumulation.Harvey (2014) also identifies free trade and the international financial system as mechanisms of accumulation by plundering, in addition to a progressive devaluation of labor power, which is reproduced at very low cost.Although the process of proletarianization is universal, the proletariat is completely heterogeneous in terms of gender, age, skills and knowledge, occupation, labor contracts, salaries etc.In our study, we indicate the particularity of migrant workers, who are socially and culturally segmented, and who constitute one of the most vulnerable populations in the world today and for this reason reinforce the general subordination of the working class.As Marx affirmed (2008a, p. 829), "the history of their expropriation is inscribed in the annals of mankind in blood and fire".

Final considerations
Does the category of migration continue to have explanatory potential, or should it be abandoned in favor of the concept of mobility?In the Letter to Annenkov (1982a), Marx criticized the way that Proudhon grasped history, based on a concept of historic evolution and the use of independent and autonomous categories.Marx defended that categories are in the first place social relations, that is, they express the way that humans produce life, and have a historic and transitory character.
Thus, we understand that the category of migration, from the perspective of historic and dialectical materialism, allows grasping the migratory process in its multiple determinations (economic, social, cultural and territorial) and in its particularity and universality and beyond the apparent and immediate phenomenon.
The ideas of mobility and permanence, for example, cannot be separated.We observe that workers move in search of work to continue to reproduce as a working class, to continue to sell their labor power and be exploited.This signifies changing to remain in the same condition.
In relation to migrant subjects, in the first place they are subjects of the working class that seeks to reproduce itself as such, in increasingly precarious, unsafe and vulnerable forms.They live in peripheral zones, often in ghettos, subject to prejudice, discrimination and violence.They are subjects with families who have race, sex, ethnicity, age and schooling.They constitute a mass of workers who are completely available for exploitation, and must move between different occupations and regions.This entire situation certainly affects the subjectivity of the migrant, constituting, as Kuenzer (2016) indicates, a flexible subjectivity from a cognitive, behavioral and ethical perspective.Migrants must easily adapt and develop the capacity to submit to the new (to reproduce the old) to detach from places and people, and from life projects and means of subsistence.They live a constant re-beginning, which does not signify the construction of a new way of life, or future prospects.This depends on the organized struggle of the working class, which has the challenge to overcome the heterogeneity that constitutes it today.