The article focuses on the interpretative argument which appeals to the intentions of the participants of the legislative process in order to explain the meaning of legal texts. The author describes differences between the argument based on the intentions of the real lawgiver and the approach to legal interpretation based on the idea of the rationality of lawgiver. The main difference concerns ideal character of the presuppositons about the rationality of lawgiver contrasted with the approach concentrated on the attempt to discover actual intentions of the participants of the legislative process. The author also describes normative and conceptual arguments concerning interpretation of law based on the intentions of the real, historical lawgiver. It is argued that this approach to the legal interpretation is justified but should not be treated as one of many valid interpretative arguments which should be weighed against each other. The article contains also an example of the use of the above interpretative argument dicussed above.