[mesmark]

I think the answer I gave him really depends on how the two sentences are said. I did tell him that for most purposes they can be concidered interchangeable.

He then followed up with this question:
Why can't we say, "There is my camera on the table." or "There is the camera on the table."

I will let you all try your hand at that explanation, but the rules are no going to the grammar books. If you know the answer that's fine but this is an off the cuff question and you can cheat. How would you answer?

I'll later tell you what I told him.