Problem. - Neurobiology, adorned with the most recent discoveries of the molecular biology, the genetics and the cognitive sciences, is present everywhere: In the report of the man with his body, with his intellectual faculties, with his perception of others and himself. Our social conducts, morality and our affects would be governed by neuronal substrata. Are things so simple? Methodology. - To try to answer this question, the author is going to use the opposition "to explain" and "understand", in a long-standing and often passionate debate which concerns the epistemology and the ontology, two modalities to be inflexible. Different thus of methods: In the mind of Dilthey, we explain the nature (submitted to the principle of the causality) but we understand the psychic life (which sends back to the sphere of the sense). Results. - If the debate to explain and understand is further and far from being simple, the author adduces to draw from it some conclusions by questioning the speech of the promising of a reductionist neurobiology which believe to explain everything including all our actions in the name of the neurobiological reason: (1) if this is the case, we would be slaves of a history which already has its fate: The neurobiological-shaped man is neurobiological, (2) this speech is based on the mechanism of the tautology, that is it goes round in circles, teaches us absolutely nothing, (3) if the same neurobiologist asserts the opposite, why while reporting me what I say, I have no precise and localizable perception of my consciousness? (4) if the consciousness has no appropriate place or, to say it differently, if there is no intellectual topic appropriate to the consciousness, then what takes place in me will remain forever untranslatable and will be condemned to the silence. To go out of one, exist thus, I need the immediate and permanent help of an other one (or of contradiction), (5) if this process is purely an event of the brain then all our actions, all our gestures, in brief all that it is allowed us to live has to take place as it takes place, (6) finally to assert it brings us nothing more because the explanation always leaves something aside: the phenomenon of the life in which he is imperceptible. The example of the alcoholic is significant: if a change of the intellectual mechanisms is responsible of his alcohol addiction, why the alcoholic, by wanting to drink "how everybody", makes as if written history beforehand was of not much importance? If the alcoholic began thinking of his own cerebral dysfunction while he lives, his life would have no shape. Indeed, if he receives the message and knows the felling about which it is a question. Indeed, if he receives the message and knows the feeling about which it is a question, he cannot, by force of circumstance, feel what his brain passes on to him: he does not witness what appears in its brain. On the other and he witnesses the world in which he lives but also on his condition of mortal. So, without objects to be cultivated, that is without the world of the presence which is the one of the existence and not the understanding, the neurobiological explanation of his alcohol addiction will concern a knowledge but will ignore any life. It means that there is well a gap to live and theorize and that the alcoholic is not reduced to a cerebral dysfunction: he is in the life of relation, that is it is capable of taking up himself by using its real-life experience. The psychopathology implications are going to show themselves here of a very big importance: any reduction comes to truncate the understanding of the man sick coach in reality we constantly have to deal with the "global and complete" man, with the anthropology of the human fate. Conclusion. - If the science brings us news discovered in this domain, it has to keep always in mind that the life remains imperceptible and deeply moving. Without this existential event which allows us "to live", the air will become unbreathable in our more and more technical-scientific world: it would like being sentenced to asphyxiation. (C) 2016 Elsevier Masson SAS. All rights reserved.