Jim- I've always disagreed with that. As Shakespeare wrote in Sonnet 59:
If there be nothing new, but that which is Hath been before, how are our brains beguiled, Which, labouring for invention, bear amiss The second burden of a former child.
In other words, if there's nothing new to be done or thought, why bother?
IMHO we know almost nothing, and there's an infinite amount of newness out there! :-)