Other early conflict theorists saw racial and ethnic conflict as more central. Sociologist Ludwig Gumplowicz, in Grundriss der Soziologie (Outlines of Sociology, 1884), described how civilization has been shaped by conflict between cultures and ethnic groups, theorizing that large complex human societies evolved from war and conquest.
Since the social, political, and cultural upheavals of the 1960s, there has been a wellspring of conflict theory-inspired analyses of race and ethnicity, many of which eventually developed into an overlapping focus on the intersectional nature of various forms of conflict and oppression.
Intersectionality is a feminist sociological theory first highlighted by leading critical theorist thinker Kimberlé Crenshaw (1989). The theory proposes that different biological, social, and cultural factors, such as as gender, race, and class, do not operate in isolation of one antoher. Rather, they are interrlated, forming a system of oppression that consists of different forms of discrimination. This theory will be further discussed under the feminist perspective of gender stratification in the chapter, "Understanding Gender Stratification and Inequality".
W. E. B. Du Bois theorized that the intersectional paradigms of race, class, and nation might explain certain aspects of Black political economy. Sociologist Patricia Hill Collins writes "Du Bois saw race, class, and nation not primarily as personal identity categories but as social hierarchies that shaped African American access to status, poverty, and power" (2000 Black Feminist Thought: Knowledge, Consciousness and the Politics of Empowerment, 42).