MENS: A categorical model for Emergence and Consciousness by Andrée Ehresmann Abstract: How do mental processes up to consciousness arise from the functioning of the brain? That is the question raised in MENS, an application to neuro-cognitive systems of the categorical model MES [1]. It is constructed as a Hierarchical Evolutive System having for level 0 the Evolutive System Neur (= sheaf of 'neural categories'). Its higher level components, called cat(egory)-neurons, are constructed via successive complexification processes of Neur. A cat-neuron represents a 'mental object' modeled as the colimit of a neural pattern it may activate; it has multiple "physical realizabilities" due to Edelman's "degenerarcty of the neural code", which we model by the 'Multiplicity Principle'. This MP allows studying emergent properties in MENS and showing they support an "emergentist reductionism" (in the sense of Mario Bunge). MP also allows for the development of a Neurophenomenology (in the sense of Varela). The dynamic of MENS is controlled by a network of 'co-regulators', each operating on its own landscape. Through successive complexificaions they develop a robust though flexible Memory, with a higher level, the Archetypal Core. This AC plays a main role for consciousness by allowing the formation of a "Global Workshop" in which a retrospection/prospection process can detect conscious events. [1] Ehresmann & Vanbremeersch, Memory Evolutive Systems, Elsevier 2007