the errors present in the tasks of a subject builder of knowledge are important because, tthey are observable and promote the process of balancing. for the researcher, clinician or teacher, the observation of constructivist errors can guarantee a minimum objectivity in the process of diagnosis and intervention. our intention in this review of theoretical work is to characterize the error inherent in the activity as part of the subject construction that, when placed to resolve a problem, taking advantage of this error is to promote the opening of new possibilities. we try to update the characterization of errors as part of the learning process and highlight the logic of children. we criticiz the positions that consider the error as evidence of disability and difficulties in solving tasks.