A continuation of this post - On the the deviations in the Mishneh Torah from the reasons for a particular law given in the Talmud.
From - http://www.mucjs.org/JLAS/reasoning.htm
"S. Ettinger, "On the Place of Sevarah (Logic) in Maimonides' Mishneh Torah" (Heb.), Shenaton Hamishpat Ha'ivri 14-15, (1988-89) 1-30. - Two pervasive themes in Maimonidean legal studies are the deviations in the Mishneh Torah from the reasons for a particular law given in the Talmud, and Maimonides' classification of commandments into Scriptural and Rabbinic categories. The present author suggests that the key to both problems lies in the notion of sevarah, which he defines as a general rational quality as distinct from the formal category of legal logic - also known as sevarah - which serves as a source for the development of laws and principles within the halakhic system. In dealing with Maimonides' tendency to provide original reasons for laws, the author distinguishes between "talmudic discussions" (masa umatan) and "definitive talmud" (talmud arukh) but concludes, following R. Abraham the son of Maimonides, that the underlying reason for Maimonides' choice of rationale for particular laws is general logic rather than criteria of a formal, legal nature. Similarly, Maimonides' categorization of Scriptural and Rabbinic laws is based upon the existence of a logical connection between the law in point and the text of the Torah, rather than on formal or semantic principles. The article concludes with an appendix criticising a recent attempt to develop a more formal approach to resolving the issue of Maimonides' deviations from the Talmudic reasons for particular laws. "