Clear - but also clearly wrong. Robin Hanson says:

After all, we seem to have little reason to expect there is a useful grand unified theory of betterness to discover, beyond what we already know. “Betterness” seems mostly a concept about us and what we want – why should it correspond to something out there about which we can make powerful discoveries?

...but the answer seems simple. A big part of "betterness" is the ability to perform inductive inference, which is not a human-specific concept. We do already have a powerful theory about that, which we discovered in the last 50 years. It doesn't immediately suggest implementation strategy - which is what we need. So: more discoveries relating to this seem likely.