Jewish denominations. Trends in modern Jewish normative ethics include: The pietistic musar tradition was continued by 18th-century rabbis such as Moshe Chaim Luzzatto in his book Mesillat Yesharim. Other musar writings were authored by Haskalah writers such as Naphtali Herz Wessely and Menachem Mendel Lefin. The musar tradition was revived by the Jewish ethics education movement known as the Musar Movement that developed in the 19th-century Orthodox Jewish European (Ashkenazi) community. The 19th- and early 20th-century Reform movement promoted the idea of Judaism as Ethical Monotheism. The writings of Abraham Geiger and Kaufmann Kohler show this approach. In the 20th and 21st centuries, liberal Reform and Reconstructionist rabbis have fostered novel approaches to Jewish ethics, for example in the writings of Eugene Borowitz and David Teutsch. Some Reform rabbis have also engaged in applied ethics by writing legal responsa (formal opinions). In 20th and 21st centuries, Orthodox rabbis often engage in applied ethics by interpreting rabbinic law (Halakha) in responsa. A dominant topic has been bioethics. 20th- and 21st-century rabbis in Conservative Judaism have also produced legal responsa on a wide range of topics. Dominant topics have included bioethics, sexual ethics, and business ethics. Leading Conservative ethicists such as the philosopher and rabbi Elliot Dorff have also written extensively on moral theory. In the 20th and 21st centuries, Jewish feminism has produced feminist Jewish ethics, using the principles of feminist ethics. Leading Jewish feminist ethicists include Judith Plaskow, Rachel Adler, Tamar Ross, Rebecca Alpert, and Laurie Zoloth. Other modern Jewish philosophers have pursued a range of ethical approaches, with varying degrees of reliance upon traditional Jewish sources. Notably, Hermann Cohen authored Religion of Reason in the tradition of Kantian ethics. Martin Buber wrote on various ethical and social topics, including the dialogical ethics of his I and Thou. Hans Jonas, a student of Martin Heidegger, draws upon phenomenology in his writings on bioethics, technology and responsibility. Emmanuel Levinas sought to distinguish his philosophical and Jewish writings; nevertheless, some scholars are constructing Jewish ethics around his innovative and deeply Jewish approach. Academic scholars of Judaism have also engaged in descriptive Jewish ethics, the study of Jewish moral practices and theory, which is situated more in the disciplines of history and the social sciences than in ethics proper (see Newman 1998). In 2003, the Society of Jewish Ethics was founded as the academic organization "dedicated to the promotion of scholarly work in