Karl Marx's theory of social change relates to the class struggle that defined the 19th century, namely that of the ruling classes (the bourgeoisie) suppressing the working classes (the proletariat), and as a result Marx's theory of social change stated that economic needs should be pursued purely on the basis of need while providing general well-being for all. This theory is and was at odds with capitalism, which, according to Marx, only helped fuel class divisions.
Class consciousness and revolution
The ideas of both class consciousness and revolution are also central to Marx's theory of social change. Under the continued exploitation of a capitalist regime, Marx believed that eventually the working classes would become aware of their plight (class consciousness).
Once aware of their situation, Marx theorized that the oppressed working classes would then organize and gain the motivation to rebel, thus taking steps to truly control their own lives by overriding capitalism as the dominant economic force. As a result, Marx thought that class consciousness was fundamental to social change.
Marx's theory is still often applied or argued in the field of economics, but has also found application in areas such as housing (as a result of rent gaps), and the use of land.