"There are more things in heaven and earth… than are dreamed of in your philosophy."
It doesn't sound like an explanation, but I take it that way. For me, Hamlet's admonition explains the confusion and uncertainty of the universe, (and, lately, the multiverse). It urges us on when, as they always will, our philosophies produce anomalies. It answers the unspoken question, "WTF?" With every door into nature we nudge open, a hundred new doors become visible, each with it's own inscrutable combination lock. It's both an explanation and a challenge, because there's always more to know.
I like how it endlessly loops back on itself. Every time you discover a new thing in heaven or earth, it becomes part of your philosophy, which will eventually be challenged by new new things.
Like all explanations, of course, it has its limits. Hamlet says it to Horatio as a way of urging him to accept the possibility of ghosts. It could just as well be used to prompt belief in UFOs, astrology, and even god—as if to say that that something is proved to exist by the very fact that you can't disprove it exists.
Still, the phrase can get us places. Not as a taxi to the end of thinking, but as a passport to exploration.
I think these words of Hamlet's are best thought of as a ratchet, a word earthily beautiful in sound and meaning: Keep moving on, but preserve what works. We need Einstein for GPS, but we can still get to the moon with Newton.