Berkeley's project is, as he famously put it, to "think with the learned, and speak with the vulgar." His metaphysical system, he is well aware, bears no resemblance whatsoever to common sense. Nevertheless, he claims, his system preserves the correctness of common sense within its own domain. Is he correct?
My answer would be Yes, and that this is right is particularly noticeable when we actually get into the details of how Berkeley's view handles skepticism. I don't have much time to lay them out at the moment, but long story short: what Berkeley does is preserve the common-sensical view of the world as the explanandum. It is nonsense to say that any scientific or philosophical advance will show that, for instance, the sky isn't really blue. There's no sense of 'really' that can bear that distinction. The fact that it looks blue is the fact that we start with; any other explanation will simply be irrelevant. It could very well be the case that the causal explanation of this explanandum will be much, much more complicated, or much stranger than you would have thought; but failure to preserve common sense "within its own domain," as Kenny puts it, is a failure to retain relevance: you've swapped out your original explananda for something else entirely.
This actually seems to me to be a serious and fundamental difference between the sort of case Berkeley has in mind and the moral case that Richard has in mind. In a moral theory common sense does not serve as the explanandum; or, to be more exact, it only does so in a moral psychology, not in an ethics. So it doesn't seem to me that you can preserve an analogy very well across the cases. But it's the sort of thing that reminds one of the painful loss of Berkeley's sequel to the Principles, where he had laid out his own moral theory. (Berkeley wrote it out in manuscript, but the manuscript was lost and he never rewrote it.) Berkeley was a utilitarian himself, so perhaps he would have had a view of the matter similar to Richard's.
