Open Future views hold that if p is a proposition making a contingent claim about the future, then p is not true (on some versions, p lacks truth value, and on other versions, p is false).
Now suppose you find out that at t0, on an ordinary autumn morning in New York City, Bill Gates tossed down a million twenty-dollar bills from an airplane, each with a sticker attached saying: "Please take this. It's a gift from Bill Gates." You are then in a position to know the following fact:
- At t0+48hrs, at least one of the twenties is not be where it fell.
But if Open Future views are true, then you don't know this, unless you know something more about t0. For if t0 is somewhere in the last 48hrs, then (1) is a future contingent. Being a future contingent, you cannot know it. For the only propositions that can be known are ones that are true. But since you do know (1), Open Future views are false.
To put it differently: Oddly, if Open Future views hold, then whether you know (1) depends on whether t0 was in the last 48hrs, or further back, regardless of further evidence. Thus, what inferences can be made from a fact depends on how far back that fact is. This is not very plausible.