Nobel Laureate in Physics
...I believe that moral questions are outside of the scientific realm. ... The typical human problem, and one whose answer religion aims to supply, is always of the following form: Should I do this? Should we do this? Should the government do this? To answer this question we can resolve it into two parts: First — If I do this, what will happen? – and second – Do I want that to happen? ... Now a question of the form: If I do this, what will happen? is strictly scientific. [The second is not.]
Sam Harris recently and infamously proposed that, contra Hume, you can derive an 'ought' from an 'is', and that science can therefore provide reasonable guidance towards a moral life. ... I don't think Harris's criterion — that we can use science to justify maximizing the well-being of individuals — is valid. We can't. We can [only] use science to say how we can maximize well-being... Harris is smuggling in an unscientific prior in his category of well-being.