To determine at the right moment the critical point where quantity changes into quality is one of the most important and difficult tasks in all the spheres of knowledge including sociology. Every worker knows that it is impossible to make two completely equal objects. By observing the norms of tolerance, the cones are considered as being equal. Our scientific thinking is only a part of our general practice including techniques. Common sense' is characterised by the fact that it systematically exceeds dialectical 'tolerance'.
Morals are equal to morals, etc.
Dialectical thinking analyses all things and phenomena in their continuous change, while determining in the material conditions of those changes that critical limit beyond which 'A' ceases to be 'A', a workers' state ceases to be a workers' state. The fundamental flaw of vulgar thought lies in the fact that it wishes to content itself with motionless imprints of a reality which consists of eternal motion. Not capitalism in general, but a given capitalism at a given stage of development. Not a workers' state in general, but a given workers' state in a backward country in an imperialist encirclement, etc. Dialectical thinking is related to vulgar in the same way that a motion picture is related to a still photograph.