The action of signs in human lives and in the evolution of cultures is to be understood in the light of semiosis,the process by which a meaning is given to all things in the world.Writing systems,as a sort of semiotic creation,evolve according to the laws of semiosis and the rhythm of human stepping ahead.This paper is an attempt to afford evidence of three relevant facts:a)A close contact,or at least a remarkable coincidence,of writing cultures in ancient times.b)An apparent and undeniable process of divergence of writing systems over centuries.c)A tendency to a new convergence of writing systems,as an ongoing process inferable from the new symbols of an increasingly globalised world.We propose that one of the elements that push these processes forward is abstraction,and we suggest that abstraction might be the leading factor in the evolution of writing and semiotic systems.