Reform Jews affirm the autonomy of the individual in matters of religious observance: that the informed conscience of the Jew, rather than a binding code of law, decides which traditional practices to take up. Emerging in nineteenth-century Europe, Reform distinguished between the ethical heart of the tradition, which it held to be eternally binding, and the ceremonial and ritual law, which it regarded as the changing garment of the faith, to be retained where it elevates and set aside where it does not.
Later Reform thought recovered much traditional practice, but always as choice rather than obligation. Reform's classical formulation came in the 1885 Pittsburgh Platform, which declared the Mosaic ceremonial laws, including kashrut and traditional dress, no longer binding on the modern Jew and reduced Judaism largely to its ethical monotheism. A century later the movement's own self-understanding had shifted enough that the 1999 Pittsburgh Principles, adopted by the Central Conference of American Rabbis, affirmed a renewed embrace of Hebrew, ritual, and traditional practices such as kashrut and Shabbat observance as spiritually valuable, while still insisting, consistent with the movement's founding principle, that no practice is halakhically obligatory and each Reform Jew decides individually which to adopt. The contrast between the two platforms is itself evidence of how far autonomy of observance has produced different outcomes across Reform's own history.