3-sphere two 3-balls. This construction is analogous to a construction of a 2-sphere, performed by gluing the boundaries of a pair of disks. A disk is a 2-ball, and the boundary of a disk is a circle (a 1-sphere). Let a pair of disks be of the same diameter. Superpose them and glue corresponding points on their boundaries. Again one may think of the third dimension as temperature. Likewise, we may inflate the 2-sphere, moving the pair of disks to become the northern and southern hemispheres. After removing a single point from the 2-sphere, what remains is homeomorphic to the Euclidean
What Is to Be Done? to become Marxists. He goes on to argue that to understand politics you must understand all of society, not just workers and their economic struggles with their employers. To become political and to become Marxists, workers need to learn about all of society, not just their own corner of it: Class political consciousness can be brought to the workers "only from without"; that is, only from outside the economic struggle, from outside the sphere of relations between workers and employers. The sphere from which alone it is possible to obtain this knowledge is the sphere of relationships (of "all" classes