Is Ethics Based on Rationality? A Criticism of Gensler's Views on Moral Rationality

On the one hand, there are a lot of ongoing disputes in the realm of ethics and, on the other hand, it is very crucial for us to reach consensus over the issue of ethics. Harry J. Gensler tries to recognize rational patterns in our ethical thinking, modeling it after formal logic, and find formal principles in ethics to make a plan for moral rationality and open a way toward this common ground. But it seems to me that this attempt is not successful. Firstly, it is not plausible for us to infer the Golden Rule (GR) from a set of formal principles derived from pure (a priori) reason and thereby is not acceptable for all. Secondly, no version of GR is perfect, each one coming with its own potential defects. And thirdly, Gensler’s discussion does not make GR more efficient in solving major disagreements in ethics. GR is absolutely essential in ethics, but it comes with all the vagueness that accompanies it, through which disagreements become possible.