The contemporary medicine goes through a deep transition with regard particularly to humanization; modern ethics
has effected sundry changes in attitudes to patients and one of them is the edification of her/his right to make choices
about her/himself. The concept of autonomy however meets the problem of assessment of the level to which the
concrete patient is capable of making decision due to various impairments and strains. One possible criterion, which
is compliant with traditional philosophy and which is based on rationality is suggested here.
autonomy, informed consent, competence, rationality, argument.