Based solely on the reviews, I'm not impressed. The search for the One True something or other goes against the typically LessWrongian idea that human meaning gets assigned to things by computational processes inside human heads. Once you bear this in mind and ask "what does 'ought' mean?", you see that a fully general mind can "ought" to do whatever it damn well pleases. Also relevant.
Optimal solutions are contained within the optimization criteria.
Language is for communication: language is public. The correctness of a meaning comes from a language community, and only from there (dictionaries are a staging post; either they reflect the language communities usages or they are wrong). The proximate assignment of meanings to words within brains is likewise either in line with usage or wrong. You need a brain to understand a word, but a brain cannot grant correctness to any arbitrary meaning-word assignment,
So you ought not do as you damn well please. Especially if you enjoy serial killing.
The "m...
Derek Parfit has published his second book, "On What Matters". Here are reviews by Tyler Cowen and Peter Singer.