Disclaimer: My sole source of this summary is the
wikpedia article.
Alienation, as defined by Marx, is the process whereby people become foreign to the world they are living in. Or more accurately, the process by which 'natural' human activities become alien to the person due to 'un-natural' activities he actually carries out. The un-natural activity most relevent to Marx is the 'labour' capitalist societies force the people into. All must work in the capitalist society to survive, and a concequence of this is alienisation of the individual and the society.
Marx believes, 'as people express their lives, so they are.' Meaning it is the activity or actions people carry out that defines them. When relating this to labour, Marx beleives as the capitalist state controls labour, it therefore controls those carrying out this labour.
Under the capitalist divison of labour, the worker is unable to freely express himself when at work. There his time is controlled by the capitalist forces, and he is unable to carry out the variety of activites he might wish. At work, man is alienated due to the fact he cannot develop himself or his personality. Work is external to the worker, it is not part of his nature, therefore it does not fulfill him. The worker therefore feels himself at home only during his leisure time, whereas at work he feels homeless. As a concequence of this when the worker is at work, he does not belong to himself but to his capitalist master. This relationship of the worker to his work is something alien. At work he is an alien, he does not belong to himself during this time, his work itself is independant of him.
This alienisation of the individual also has an affect on the community. At work man is alienated from himself, and from others. He is unable to express himself as he sees fit, and is confined to activity that is sanctioned by his capitalist master. This affects the whole community as large portions of the workers day do not belong to him. He cannot carry out 'natural' human activity, or interact in a 'natural' way with others. This alienates the individual, and alienates the individual from the society.
Marx's theories on human nature are that man must carry out 'natural' activities in order to progress as an individual. Unless he is carrying out these activities he remain unfulfilled. As it is his actions that define him, being alienated from these natural actions will have negative concequences for the individual and the society.
I hope this is of some use, i see now why you hate sociology!
8)