The biologist and physician Henri Atlan, who had published in his time, a much noticed essay "Between the crystal and the smoke", has just issued a book on Spinoza and the current sciences of cognition. The publication of this book represents an excellent opportunity to revisit past and current conceptions of the relationship between body and mind. For a long time it was thought that the mind could be represented by a soul distinct from the body, the soul and the body being considered as two disjoint entities. The soul was supposed to control the body, but the link between these two entities remained mysterious. Such a conception prevailed until the end of the Middle Ages and the beginning of the Renaissance. The interaction between the soul and the body, however, remained problematic. The way in which the immaterial soul can control the body had been the subject of a question put to Descartes by the Princess Elizabeth of Bohemia in 1643. For Descartes, the soul is the seat of thought. He placed it in the pineal gland. The soul identifies with the person, as a source of thoughts and feelings. The body is only a vehicle, a machine that allows the human being to survive in his environment. The animals being devoid of soul, are reduced to the state of machines and Descartes does not recognize them thoughts, feelings, or even sensations. Advances in science have highlighted the role of the brain as the seat of reflection. Neuroscience has benefited from new technologies, including medical imaging, which has made it possible to locate mental functions in different parts of the brain. Descartes has been criticized for making the soul a duplicate of the human being. a homunculus that would be housed in the brain and that would perceive all the messages that it receives, thus creating the logical risk of a regression to infinity. Today, the brain is generally perceived as the sole seat of thought. The notion of an immaterial soul then becomes obsolete. At the same time, the existence of any form of "spirit" that is different from matter is called into question. The eminent neuroscientist Antonio Damasio denounced the conception of a separate body and soul, calling it a "Descartes' error". Against Descartes, Damasio wants to give reason to Spinoza, who has adopted a monism of body and mind. Henri Atlan resumes his arguments, not hesitating to affirm that the philosophy of Spinoza brings to the current sciences a more important contribution than those of the other great philosophers of the same period, Descartes, Pascal, Leibnitz as well as other more recent and even contemporaries. But he blames Damasio for interpreting Spinoza's philosophy in terms of materialist monism, which poses problems of coherence in his interpretation of the links between body and mind. In addition, according to Henri Atlan, this materialist position departs from the position defended by Spinoza, who claimed the existence of two attributes of Nature, none of which could fully identify with the other, represented in the human being. human respectively by body and mind. It is this way of escaping a reductionism that is either materialistic or idealistic, which, according to Henri Atlan, constitutes the whole interest of Spinoza's position. However, his analysis does not escape, itself, contradictions. Indeed, like many current scientists, Henri Atlan adopts a physicalist position, consisting in admitting that the functioning of the mind is governed by the laws of the current physics. In this case, is not the attribute "spirit" a mere illusion?
In fact, it is possible to interpret Spinoza's monism in two different ways. Following the first, it would be a monism foreshadowing the materialistic monism that Damasio defends. In this case, it is unclear what clarification about the functioning of the mind can inspire a current scientist reading the Ethics, whose language (substance, attribute ...) seems far removed from the current scientific language. According to a second interpretation, Spinoza defends a form of panpsychism, the nature of which remains to be elucidated. In this case, a reflection on his work could bring an opening to the current science, without requiring to leave the domain of Nature. This is clearly not the path chosen by Henri Atlan and, in these circumstances, it is difficult to understand how his position differs from that of Damasio, other than at the level of a petition of principle.

En fait, il est possible d'interpréter le monisme de Spinoza en deux sens différents. Suivant le premier, il s'agirait d'un monisme préfigurant le monisme matérialiste que défend Damasio. Dans ce cas, on ne voit pas très bien quel éclaircissement concernant le fonctionnement du mental peut inspirer à un scientifique actuel la lecture de l'Ethique, dont le langage (substance, attribut ...) paraît bien éloigné du langage scientifique actuel. Selon une seconde interprétation, Spinoza défendrait une forme de panpsychisme, dont la nature reste à élucider. Dans ce cas, une réflexion sur son oeuvre pourrait apporter une ouverture à la science actuelle, sans nécessiter pour autant de sortir du domaine de la Nature. Ce n'est manifestement pas la voie choisie par Henri Atlan et, dans ces conditions, on comprend mal en quoi sa position diffère de celle de Damasio, autrement qu'au niveau d'une pétition de principe.