Well, there are many more factors than simply a single passing claim of something to inch it more toward validity. Your invisible dinosaur came from your imagination in a second or two. The idea of ghosts has been brought up and re-brought up all over the world, all throughout recorded history. While that is far from solid, to equate the two scenarios (invisi-saur vs. ghosts) is silly.
There was absolutely nothing wrong with that statement. You not being able to prove something doesn't exist doesn't give it any further validity, but I doubt that's what he was implying.
edit: forgot to put in the bolded words
Edited by _Only, 13 June 2012 - 08:25 PM.