Seems like we had a pretty good discussion here. Well, I wrote "to be seen" or "to be heard" for mieru and kikoeru, and these explanations come from WWWJDIC.... seems like you cannot directly translated these words from Japanese to English. (WWWJDIC even states that they are Intransitive verbs ... but I don't think it's the same as "intransitive verbs" in English)

By looking at the examples, the difference between miru and mieru, kiku and kikoeru are obvious.

They are intransitive verbs in Japanese (one might make the case that all verbs in potential form are intransitive in Japanese since they take が rather than を in the default context), but not in English. You typically translate them as "can see" and "can hear," but I suppose you could translate
海が聞こえる as "The sea can be heard" rather than "I can hear the sea."