What is striking when you talk with mathematicians is that sparkle in their eyes, and their sudden joyful voice trying to share with you a concept, a theory. They continuously use words such as invention, beauty, freedom. You then ask yourself : how such a rich language, this quasi-philosophical proposition about the world becomes rejected by a majority, 'the only discipline where one prides itself to be bad at it'! But for 40 years, mathematicians have become essential in sickness and in health!