A social class is, at its most basic, a group of people that have similar socialstatus.
The relative importance and definition of membership in a particular class differs greatly over time and between societies, particularly in societies having a legal differentiation of groups of people by birth or occupation.
In the well-known example of socioeconomic class, many scholars view societies as stratifying into a hierarchical system based on economic status, wealth, or income.
Using wealth as a dimension, many have used a a bi-partite model to view societies, from ancient history to the present day:
an Upper Class of the immensely wealthy and/or powerful
With the social changes stemming from the Industrial Revolution, a gradually developing urban middle class developed in most Western countries, producing three strata:
an Upper class of the immensely wealthy and/or powerful
a Middle class of managers and highly paid professionals
a Lower class of people paid average or low wages or receiving "welfare." Some are homeless.
Some advocates view this as an oligarchy, i.e., a ruling class with the assistance of a middling class dominating the working class. Other theories are less critical of the upper classes, seeing them as protectors or innovators (not mere leeches).
When sociologistss speak of "class" they usually mean economically based classes in modern or near pre-modern society. Modern usage of the word "class" outside of Marxism generally considers only the relative wealth of individuals or social groups, and not the ownership of the means of production.
The sociologist Max Weber formulated a three-component theory of stratification, with class, status and party (or politics) as conceptually distinct elements.
In Marxist terms a class is a group of people with a specific relationship to the means of production. Marxists explain history in terms of a war of classes between those who control production and those who actually produce the goods or services in society (and also developments in technology and the like). In the Marxist view of capitalism this is a conflict between capitalists (bourgeoisie) and wage-workers (proletariat). For Marxists classes are antagonistically opposed to one another. This antagonism is rooted in the situation that control over social production is necessarily control over the class which produces goods and the exploitation of workers by the bourgeoisie.
The most important transformation of society for Marxists has been the massive and rapid growth of the proletariat in the last two hundred and fifty years. Starting with agricultural and domestic textile labourers in England, more and more occupations only provide a living through wages or salaries. Private enterprise or self-employment in a variety of occupations is no longer as viable as it once was, and so many people who once controlled their own labour-time are converted into proletarians. Today groups which in the past subsisted on stipends or private wealth -- like doctors, academics or lawyers -- are now increasingly working as wage labourers. Marxists call this process "proletarianisation," and point to it as the major factor in the proletariat being the largest class in current societies in the rich countries of the "first world."
"Bourdieu seems to have fairly rigid notion of high and low classes comparable to that of Marxism, insofar as their conditions are defined by different habitus, which is in turn defined by different objectively classifiable conditions of existence. In fact, one of the principal distinction Bourdieu makes is a distinction between bourgeois taste and the working class taste."
The extent to which classes are important differs also in western societies, though in most societies class as an objective measure has very strong empirical effects on life chances (e.g. educational achievement, life-time earnings, health outcomes). Only in the strongly social-democratic societies such as Sweden is there much long-term evidence of the weakening of the consequences of social class.
The effect of class on vote or life-style is more variable across countries and over time.