Wow, these three comments have just mirrored my own recent thoughts to the greatest extent I can remember. I present to you the Infinite Curiosity Loop:

http://funnylogic.com/times/txt/2009-11-infinite-curiosity-l...

And for what it's worth, the definition of intelligence has been on my mind a lot.

If you'd like to explore this subject in a structured way, then there's a large library of philosophical writings on the subject :). I think Hilary Putnam's essay on "Brains in a vat"[1] may be a nice starting point, from which can explore both earlier and later work.

[1] http://evans-experientialism.freewebspace.com/putnam05.htm

The letter 'g' is a completely arbitrary shape. Similarly an entire word 'everything' is just an arbitrary shape (though subdivided into constituent organized blobs of arbitrary shape). Letters and words seem to be symbols/code that stand for something else, and that something else might be raw sensory neuron patterns or something (imaging an apple with your eyes shut might be a trick to trigger that raw data without needing external stimulus to do so, such as seeing a real apple). Even the "sesame street" concept of up/down might require some sort of raw inner ear balance and sight sense to experience.