Bernard d"Espagnat. We have the pleasure of welcoming among us Alexei Grinbaum. During our last session, thanks to Jean-Michel Raimond's brilliant presentation, we saw experimentally that physical systems which have a typically quantum behaviour at time 0+ have a classical behaviour later on. This constitutes a very strong indication, not to say an experimental proof, that there are not two types of systems, one obeying quantum physics and the other obeying classical physics, but on the contrary that there is only one physics, even if depending on the circumstances, physical systems can appear to us either under a quantum or a classical aspect.