Full Idea
If ethics is a matter of decision, and we must face the responsibility and burden of those decisions, this ignores the obvious point that if we are uncertain, then we are uncertain what to decide.
Gist of Idea
Taking responsibility won't cure ethical uncertainty by; we are uncertain what to decide
Source
Bernard Williams (Ethics and the Limits of Philosophy [1985], Ch. 9)
Book Reference
Williams,Bernard: 'Ethics and the Limits of Philosophy' [Fontana 1985], p.170
A Reaction
Good point. The defence would be that the decision itself contains the seeds of certainty. Do something rather than nothing, and the sense of it will emerge. Modify as you go along.