After brief considerations about intelligence, a comparative study between biologic and artificial intelligence is made. The specialists in Artificial Intelligence found that intelligence is purely a matter of physical symbol manipulation. The enterprise of Artificial Intelligence aims to understand what we might call Brain Intelligence in terms of concepts and techniques of engineering. However the philosophers believed that computer-machine can have syntax, but can never have semantics. In other words, that they can follow rules, such as those of arithmetic or grammar, but not understand what to us are meanings of symbols, such as words. In the present paper it is stressed that brain/mind complex constitutes a monolithic system that functions with emergent properties at several levels of hierarchical organization. These hierarchical levels are non-reducible to one another. They are at least three (neuronal, functional, and semantic), and they function within an interactional plan. The brain/ mind complex, which transform informations in meanings, deals with problems by means of both logical and non-logical mechanisms; while logic allows the mind to arrange the elements for reasoning, the non-logical mechanisms (fuzzy logic, heuristics, insights) allows the mind to develop strategies to find solutions. The model for construction of the "intelligent machine" is the operating way of the brain/mind complex, which does not always use logical processes. The role of information science in Artificial Intelligence is to search for knowledge itself (virtual knowledge), rather than to simply attempt a logico-mathematical formalization of knowledge.
brain; artificial intelligence; fuzzy logic; logic thought