Objective morality as a proper basic belief

[henryp]

Saying rape is wrong because it objectively causes harm only shifts the argument to whether or not causing harm is wrong.

Sure, but it's an argument that I'm going to win with ease.  

If someone is trying to rape you, you can stab them in the face, and that would not be wrong in my opinion.  Stabbing someone in the face certainly qualifies as causing harm.  So you'd at a minimum have to sharpen up the idea of 'doing harm'.