a tree would cease to exist if no one was looking at it [sound familiar?]

Reminds me of a favorite variation on this theme:

"If a man is talking by himself in the forest, is he still wrong?"

And back to our regularly interrupted thread-theme:

I know some of the work of Berkeley (and I live in the city that bears his name, in CA), but mostly in summary form rather than having read it. I'm curious why Berkeley chose Hylas as one of the participants in his dialogues - he was a friend of Hercules who, whilst on a journey with the strong fella, went to a spring to get some water and was bewitched/seduced by the nymph or nymphs who lived in the spring, who were themselves bewitched by his good looks. He remained with the nymphs, lost forever to the world of mortals.

How does this history make him appropriate to take the role of the proponent of the independent existence of matter in the Berkeley dialogues? Or is the name just Berkeley's equivalent of Joe Schmoe? Or perhaps he sees Hylas' faith in the existence of matter as akin to his being entranced by the mythical nymphs? Or perhaps I should cease all the speculatin' and hand-wavin'?