Given that many inventions are collaborative, that's really difficult to do these days. A lot of inventions require capital and that doesn't come if you work entirely in secret, with the exception of classified government research I suppose.
@jk,
I was thinking that a lot of phony patents have been filed after products had long been in use and I was wondering if the authors of the America Invents Act considered this when they applied the law. I'm glad that Smuckers' claim to the PBJ wasn't recognized. There are other examples as well though. For instance, Dr. Vinod Gupta of NISCAIR has stated that there are 2,493 US patents that were taken directly from Ayurveda and in use for thousands of years for the same purposes and in the same manner as the filed patents' state. Will these plants now be monopolized for medicinal purposes?

