This chapter introduces a brief genealogy of conceptions of segregation, addressing how they emerged from particular contextual and epistemological conditions that have shaped our imagination of the spatiality of segregation and how it explains social segregation. To assume location and distance as a proxy for social division obscures the subtle roles of space in social segregation and ignores people's daily efforts of converting their spatial reach into situations of encounter and opportunities for interaction. The chapter discusses break away from the spatial reduction of segregation to the social division of space by asserting the integrative and segregative potential of encounter and identifies the central role of mobility in the generation of circumstances for encounter. It analyzes encounter-producing mobility to social difference, showing income to be an active factor in shaping mobility, especially in unequal societies. Social differences can only be naturalised if the possibility of encountering the other is firmly established as a recurring event in daily life.