Mao Zedong's concept of ＂one divides into two,＂ derived from Hegelian/ Marxist dialectical logic, was influential among French leftist thinkers in the 1960s, including Jacques Rancière and Alain Badiou. While ＂one divides into two＂ turned out to be a slogan in China used for political purges in the 1960s, it left a different trace on the philosophical thoughts of Rancière and Badiou in their later developments. The stake of the issue here is whether the division of ＂one＂ into ＂two＂ is a process of internal partition based on the fixated ideological positions, whether the count of the subject as ＂one＂ has already been prescribed and implicated by certain conceptual structure of the One, be it God, Nation, Party or the Capital, or whether one dividing into two is a constant happening in the dialectic movement of the matter. Both Rancière and Badiou proposed the concept of the void (le vide) to disrupt and to relocate the given logic of the count through the dialectic process of ＂one divides into two.＂ Their interpretations of the ＂void,＂ however, point to different directions. For Rancière, the partage of the sensible indicates the sharing and partaking of the whole as one part, a part that is partitioned within the whole, with a given location. The void between the counted part and the uncounted part, part des sans-part, is the écart-the gap, the empty space, interval, difference-inscribed within the logos where politics begins. For Badiou, counting as one is always already within the regime of cut and is at the edge of the void. The void is the horlieu or non-lieu, or the empty set in the topological sense, which allows something new to happen. This paper examines how Rancière's and Badiou's philosophies diverge on the concept of the void while at the same time provide their re-definition of radical equality and the common.