Naturalism and Human Nature

This claim(adopted by authors like Sam Harris) argues that we should use the tools of modern science to assess what human beings want and what their characteristics are, for instance, by looking at evolutionary biology or psychology and develop an ethical framework in accordance with human nature, which most people would accept. 

The flaws with this claim are-

1. It evades Hume's argument that we cannot know what values we should accept. 
2. Human beings may not be ‘naturally’ inspired to impartially doing what is good as genetic research indicates that humans are prone to being selfish and irrational.