I read a post by Rosa Rubicondior about a conversation that Dan Barker had with a guy called Jason Gastrich and you should probably go read it since it’s great.
Anyway, it got me thinking and I’m writing this mostly to firm up my understanding of the concept.
The basic premise is this: a god who knows the future is a god without free will, with limited power. A god cannot both know the future and be omnipotent, have free will and make decisions.
Why this is, is pretty straightforward; I’ll try a simple example.
Lets assume Yahweh, in the year 1500 BCE, knew for certain that on December 21, 2012 the world was going to end by an asteroid hitting the earth. Let’s assume he told a man called Moses to write this down in such a way that it would form part of the Talmud and later the Bible, as a prophecy. So Yahweh makes a prophesy in 1500 BCE that the world ends in fiery Armageddon in December 2012.
Fast forward to July 26, 2012. Yahweh knows on this day that the world is going to end in fiery Armageddon on December 21 by an asteroid strike and he tells a guy called Harry Llama this inconvenient truth through a vision. Now, Yahweh has been absolutely, infallibly correct about the fact of the world ending December 2012, every day for 3512 years, or about 1.2 million straight days.
Harry Llama, a bit perturbed about this revelation, gets together a whole bunch of good Christians on the 27th of July and, as the Holy Bible prescribes, they pray together to Yahweh to stop the asteroid from destroying the earth.
Now Yahweh has a bit of a dilemma. If he chooses (assuming he has this choice…) to avert the disaster and cause Armageddon to not occur at the prophesied time at the prophesied place then he would have been wrong for 3512 years. If Armageddon does not occur, Yahweh would not in fact have known that the event would occur – he would have been flat out wrong for 3512 years. This means he is not omniscient.
If Yahweh is guaranteed to be omniscient, he then can not do anything to avert the disaster as this would cause him to not be omniscient since averting the disaster forces Yahweh to be wrong, it forces him to not have known something. If Yahweh can not do something, it means he is powerless, he is not omnipotent, he has no free will.
Now, this example aside, it applies to absolutely everything an omniscient god might know. If a god is omniscient – and therefore prescient – it cannot also be omnipotent and have free will or free agency.
If a god knows for certain the outcome of a future event and then causes the outcome of that event to change, it never knew the certain outcome. If a god knows for certain an outcome and cannot change the outcome, it is not omnipotent and does not have free agency.
The god of the bible? By definition, it does not exist.