modern artists were concerned with portraying everyday objects and contemporary scenes. Modern art could also be seen as reactionary, since many of the subjects during certain art movements represented "current" issues: was, social politics, high society, artistic hierarchy, pop culture, music, poetry, celebrity icons, etc.
And even then, some modern artists would say their artwork doesn't represent one thing, but it represents anything each viewer interprets the piece as. Modern art has MANY definitions, and there are lots of artists to choose from, but you can count on thisthey all think outside the box!