National audienceAging is not a disease. Age changes occur in every adult animal. It takes place in all species. Yet, malign tumours, and neurodegenerative diseases are growing with age. Nobody dies from aging. Death results from age-associated diseases. Muscular and digestive atrophies are rising with age. But can we say that digestive atrophy lead to a bad nutrition, or is it not the contrary? Where is the chicken and where is the egg? We are closed in a vicious circle. A vicious circle is not a simple cycle. It's an irreversible phenomenon that happens when a system of objects is acting on itself. Vicious circles are coming too at the molecular level. This paper tries to show that the destruction of elastin and of fibronectine in connective tissues produces a self destruction effect. Von Neumann showed that we can imagine a model of self reproduction with the help of reproductive automata. We attempts to show that nature has imagined a model to produce self destruction, with the use of degradation of fibronectin and elastin in peptides. This self destruction process is neither purely stochastic, nor genetically programmed. It's an epigenetical process. It's not present at the beginning, like an a priori instruction, it is emerging. Then we try to give a specific unusual philosophical definition to the word "emergence.
