In Marxist thought, estrangement, or alienation, is a central concept describing the profound disconnection experienced by individuals within capitalist society. It refers to the separation of workers from various aspects of their labor, their products, their fellow human beings, and ultimately, their own human potential.

Marx identified four primary forms of alienation under capitalism. Firstly, workers are alienated from the product of their labor. The goods they produce do not belong to them but to the capitalist who owns the means of production. The more they produce, the less they possess.

Secondly, workers experience alienation from the act of labor itself. Instead of being a fulfilling and creative activity, work becomes a forced means of survival, controlled and dictated by the capitalist. There is little autonomy or intrinsic satisfaction in the labor process.

Thirdly, capitalism fosters alienation from other workers. Competition for jobs and the hierarchical nature of the workplace can create divisions and prevent the development of genuine solidarity and community among the proletariat.

Finally, and most profoundly, workers suffer from alienation from their own human essence or species-being. Their capacity for creative, conscious, and social activity is stifled by the dehumanizing conditions of capitalist production, reducing them to mere instruments of labor.

Marx argued that this estrangement is not an inherent aspect of human existence but a direct consequence of the capitalist mode of production and its emphasis on private ownership and profit maximization. The very structure of capitalism necessitates the exploitation and dehumanization of the working class.

Overcoming estrangement, according to Marx, is intrinsically linked to the abolition of capitalism and the establishment of a communist society. In a communist system, where the means of production are collectively owned and controlled, labor can become a truly human and fulfilling activity.

By eliminating private property and the division of labor based on exploitation, communism aims to reintegrate individuals with their labor, their products, their fellow human beings, and their own human potential. This re-appropriation of their alienated capacities is central to human liberation in Marxist thought.