When debating Calvinists about if God knows the future, they often point to prophecy as a way to claim that God must know every detail about the future. But by their own standards, this is highly suspect. Take for example the prophecy of Tyre.
1. In the prophecy against Tyre, the natural understanding is that it is against the current residents (not those living 250 years down the line).
2. The prophecy specifically lists what King Nebuchadnezzar would do, which never happened.
3. The Bible later concedes that the prophecy failed, and King Nebuchadnezzar is given a consolation prize of Egypt.
4. The prophecy also claims that Tyre would never be rebuilt. It was.
5. The Bible never records a successful completion of this prophecy (it records a failure), and success is only post facto read into the text by apologists.
On top of this, when the prophecy talks about “nations” coming against Israel, Nations is sometimes figuratively used for “troops” or a collective term for Gentiles. The concept is that Tyre would be swarmed and enemies, not that Tyre would hold out for 250 years then fall.
But Calvinists insist that the prophecy of Tyre was fulfilled. They claim that it was fulfilled in the person of Alexander the Great a full 250 years later. No unbiased person would read the original prophecy and then believe that if Tyre was destroyed 250 years later the prophecy would be fulfilled. In other words, Calvinists accept almost any event as “fulfilling” a prophecy (even if the prophecy never alluded to that particular type of fulfillment). So, in what way would God have to know the future if all He had to do was a tangential action sometime, somewhere to “fulfill” a prophecy?
Using the Calvinist standard of prophecy fulfillment, no one would have to know the future to make prophecy come true. This fact even undermines more specific prophecy, such as King Cyrus. It could only be coincidental that the fulfillment was close to face value of the original prophecy.