Greater than zero.

You wanna tweak your melon a bit? Look up "Last Thursdayism." It's a thing — due to the way short term and long term memory work, the theory goes that anything before "last Thursday" is a lie. It's an arbitrary day of the week. The movie Dark City played off of this, when the — I forget what they were called — did their tuning and rearranged things and swapped peoples' memories around.