Architecture has always been a difficult subject matter for semioticians. On the one hand, space is not easy to formalize in any way, and, on the other hand, architects have not helped at all, on the contrary, they uncovered a lot of problems and never found solutions. The excellent research work made by the IASS coordinated by professor Pierre Pellegrino, and also the PHD program in the School of Architecture in Tunisia, thanks to the late professor Alain Renier, are two examples of endured effort, that were very often not recognised by universities and professional institutions. The situation is slowly changing, at last, and a surprising impulse is coming from the design by computer processes, since now architects need more theories in order to justify their new expertises. My contribution will show how these new processes can increase the coaction between semiotics and architecture, starting from the probabilistic epigenetic model defined by the late professor Gilbert Gottlieb. This coaction between architecture and semiotics, demands a better clarification of the deep relationships between cognitive construction and cognitive communication, both in architecture and in semiotics, an old topic that can today be revisited. From this point of view, some cognitive anthropological recent developments (E, Hutchins, D. Kirsh and others) can show the right way to go. Then, following the last work by Professor Alva Noe, architecture and semiotics could follow their own developments, hand by hand, in a similar way art and philosophy can interact. They can be two different ways of organization of our lives, without the subordination of one by the other. Some examples of this coactive interaction between semiotics and architecture constitute the conclusions of this communication.
