> I believe that Michael was
> referring to Plato's reference to the observer sitting within a
> cave, outside of which a fire is burning. The observer can see
> that the fire is projecting moving shadows on to the cave wall,
> which he -- the observer -- mistakenly takes for reality.
I always though that this was a meaningful allegory, so after writing the above (from ancient memory) I thought I would check the source.
It is in Plato's Republic, Book VII, and if anything my memory did not do it justice.
For those who are interested, click here: and scroll down to Book VII.