Can we make sense of our moral claims through either error theory or non-cognitivism?

This paper is based on the arguments made by the authors in the following books:

1. Michael Sandel: Justice: What’s the Right Thing to Do? ISBN: 0374532508
2. Russ Shafer-Landau: What Ever Happened to Good and Evil? ISBN: 0195168739——you do not have to use these sources but if you can find it online ( I know Sandel is online) that would be great.