Says if you took early PS1 and PS2 titles you would never have imagined each console would have sold over 100 million units.
Speaking to Game Informer Magazine, Harrison has responded to criticism of the PlayStation 3 launch software, noting that it's "always dangerous to judge any system by its launch line-up".
"You only have to go back to the games that launched PlayStation 1 and PlayStation 2," said Harrison. "If you took those few dozen titles and analysed them, you would never have imagined that either of those formats would have on to sell over 100 million units each."
That said, it will be this holiday period, traditionally a boom time for new software releases, in which the PlayStation 3 can be more fairly judged.