Based on glial-neuronal interaction a formalism (negative language) for the generation of intentional programs is proposed. An intentional program generates a specific multirelational structure in an inner or outer appropriate environment according to the principle of feasibility. After description of the glial spatio-temporal boundary-setting function in its interaction with the neuronal system, it is hypothesized that intentional programs may be generated in glial networks (syncytia) in line with the formalism of negative language. Gap junctions are interpreted as multirelational negation operators, generating cycles in a permutation system. These cycles could represent intentional programs that can either be realized or not in neuronal networks embodying a permutation system. The feasibility of these intentional programs is essentially dependent on appropriate environmental information. Since the realization of intentional programs in neuronal networks allows high degrees of freedom, the problem of free will is tackled, as well. Free will is defined as the subjective freedom to choose between the inner determination of intentional programs and the overdetermination of their feasibility in an appropriate environment. Finally, the possible implementation of the proposed brain model in robot brains is briefly discussed.