In: "soc.culture.jewish FAQ: Torah and Halachic Authority (3/12)"

[Topic: WHEN ORTHODOX RABBIS DISAGREE ON A RULING, as opposed to a disagreement on a ruling between an Orthodox and a Reform rabbi]

[...]
The Orthodox rabbis would both say that their halachic rulings are in line with the tradition of Torah learning*, all the way from Sinai, and that their difference is in details. The Reform rabbi, however, might derive a ruling from other sources of morality, such as secular ethical notions of equality.

[...]
the Orthodox scholars believe there was no disagreement over first principles, while Orthodox and Reform differ significantly on major principles, such as Torah being from G-d, and the authority of individuals to decide halacha for themselves.

* Refers to the Oral Law as well as the Written Law [editor's note].