I'm down with the basic idea that we can approach morality from a reasoned, scientific viewpoint and develop a moral system that is better and more internally consistent than those offered by religion. But I still think Harris has it mostly wrong.
I summarized it pretty well on my old blog, here. Harris basically wants to use suffering and happiness as the standards by which to develop a scientific moral system. Here's the gist of why that's not a hot idea:
Happiness and suffering are feedback signals evolved to reinforce the type of behavior that leads to the propagation of genes into future generations. Things that produce a nice rush of neurotransmitters to the brain include earthly pleasures such as eating foods high in sugar and fat, and of course, sexual arousal. Pain is a punishment signal meant to direct an organism away from behaviors that have an adverse affect on genetic propagation, bodily injury being the most obvious. The release of the chemicals that give rise to the subjective experiences of happiness and suffering are old subcortical regions whose purpose is to crudely guide our behavior through reinforcement. Should we really be using them as the ultimate guide to what is good and what is bad?I sympathize with Harris' motivation, but his implementation is horribly flawed.