The study of law is, first and foremost, the study of a human practice. The full account of the practice of law can be given by explaining legal rule-following behaviour not only from the scientific, i.e. objective, perspective, but also from that of the person who must decide how she will respond to the law. Answers to various and persistent jurisprudential questions – such as “what is the law?” or “what is the difference between law and morality” – require an account of what it means that a person accepts a legal rule as a legal rule and not as a rule of any other normative system. Unfortunately, it seems that this subjective point of view is beyond the reach of scientific method. Science allows us to study the social behaviour in the legal context, but it does not allow us to distinguish between the acceptance and non-acceptance of legal rules.