"Obviously you are here... why can't I see you?"

Well, I've been there a few times, certainly... :)

Why, however, do you choose sight as your medium of reality? Has a perception ever been confirmed by non-perception? The witness has only itself to confirm the veracity of its testimony.

You can know that you exist, by virtue of being the one pondering; from this, can one know that existance - whatever it be, and who can state with authority that they are as they percieve themselves to be, anyways? - exists, as a prerequisite for self-existance, in whatever form it truly is.

That existance extends beyond self cannot be proven. That existance ceases at the boundaries of self cannot be proven - and even if we humor perception for a moment, what are the boundaries of self? What are you, without the oxygen you breathe in? What is this, without the plant which breathes you in return? Are you not that tree falling in the forest - or do you breathe its sound? Can you show me the point where one thing stops, and another begins?

I am, in truth, the walrus - and that is why I am here (or there, if one prefers)... but why do you insist on seeing walruses, when fractals shall suffice?

...just a few questions from a curious entusked mammal...