"The bourgeoisie and the petty bourgeoisie have armed themselves against the rising proletariat with, among other things, 'culture.'"

This quote by George Grosz is describing the class struggle in between the bourgeoisie and the proletariat. The bourgeoisie, or the upper class, and the minor bourgeoisie, or the middle class, have actually utilized culture as a weapon to preserve their power and benefit over the proletariat, or the working class. This is done by using culture to produce a divide in between the classes, with the bourgeoisie and petty bourgeoisie having access to greater culture and the proletariat having access to lower culture. This divide reinforces the power of the bourgeoisie and petty bourgeoisie, as they have the ability to use their access to greater culture to maintain their power and advantage. By producing this divide, the bourgeoisie and petty bourgeoisie are able to maintain their power and advantage over the proletariat.