I'll grant that this isn't what "Philosophy" is in 2009, but it seems rather important to understand that that is what Philosophy was in the ancient world. If the idea of dying for three days and then being resurrected sounds familiar, well... yeah. But also, yeah. Please take the time to read that second link, the one referring to a poem by Hafiz.
Well, again: I'm happy to forfeit the terminology -- I understand that "capital in the institutional realm in which we live" revolves to a certain extent around a "safer" (i.e., more toothless, less mystical) definition of Philosophy.
But if you want to understand correctly what it was that the famous classical Philosophers were proposing as an alternative to Rhetoric--if you want to have a correct understanding of the historical context of the Platonic dialogues--you have to understand this more complicated definition. As the History Channel suggests, those who went to the caves were effectively part of a "cult," and would have held little resemblance to most contemporary professional Philosophy professors. The easiest distinction to make is to argue, as I have before, that it's hard to imagine a contemporary Philosophy professor dying for his convictions concerning Derrida. But Empedocles, Socrates, and others were willing to go that route for their convictions. If you imagine a person like Socrates as a silly old man who just liked to talk and bicker, I think you're badly misreading Plato.
The "Truth" that seems so out of vogue to most contemporary academics was nothing less than the experience that one underwent in those caves. It was not a silly and oversimple imaginary idea that was unconnected to the actually-existing world, but a vivid (and incommunicable) intellectual/spiritual actuality. It was very likely in these caves that Parmenides first perceived the "Oneness" that obsessed him, that Socrates first conceived of "the Good," and so on. To argue against those experiences from the perspective of one who has not "visited the underworld" may earn a person tenure, but it does not diminish the lasting influence of Wisdom or Truth in the actually-existing world.
But thanks for playing!