The older argument

1. God knows you will be in class.
2. If God knows that p, then necessarily p.
3. So, necessarily you will be in class.
4. If something is necessary, you’re not free with respect to it.
5. So, you’re not free with respect to being in class.

Boethius/Aquinas response

Premise (2) is ambiguous between:

2a. If God knows that p, then: (it is necessary that p).

2b. It is necessary that: (If God knows that p, then p).

But 2a is needed for the argument to be valid and 2b is what is true.

Analogies:

a. It’s obvious that: (if the 30th digit of pi is 9, then the 30th digit of pi is odd).

b. If the 30th digit of pi is 9, then: (it is obvious that the 30th digit of pi is odd).

a. It’s guaranteed by the syllabus that: (if Alice is caught cheating, Alice gets a zero).

b. If Alice is caught cheating, then: (it’s guaranteed by the syllabus that Alice gets a zero).

The fixeity of the past argument

1. If you have the power not to do A, you have the power to make God not have foreseen you doing A.
2. God’s having foreseen you doing A and God’s not having foreseen you doing A are facts about the past.
3. You have no power to make a fact about the past be.
4. So, you do not have the power not to do A.

The Pike version (simplified)

1. God believed you will do A.
2. If you have the power not to do A and God believed you will do A, you have the power to (a) make it not be the case that God believed that you will do A, or (b) make it be the case that God believed something false.
3. You do not have the power for (a).
4. You do not have the power for (b).
5. So, the following is false: you have the power not to do A and God believed you will do A. (by 2, 3, 4)
6. So, you do not have the power not to do A. (by 1 and 5)

Ockham’s way out

We can make past soft facts be. (E.g., voters in 2020 brought it about that Jill Jacobs in 1976 married the 46th president of the United States.) That God believed you will do A is equivalent to the fact that you will do A and hence is soft.

Paul and the ants

Suppose God wants the ants to survive, and would have moved them had it been the case that Paul would mow the lawn. That the ants were moved (or unmoved) is a hard fact. But it’s up to Paul!

Plantinga’s suggestion

When we say the past is fixed, we mean that various past truths are accidentally necessary.

p is accidentally necessary at t iff p is true at t and no possible action that an agent has the power to do at t necessarily implies that p is not true.

This allows the ant colony moving in to be accidentally necessary, and hence captures our intuition about the fixedness of the ant colony.

Prophecy problem

Suppose God announced that I will mow the lawn. If I don’t mow the lawn, that necessarily implies that God did not announce that I will mow the lawn since God cannot lie. So God’s announcement is not accidentally necessary by Plantinga’s definition. But it should be just as fixed as the ant colony case.

My suggestion

Stop thinking the past is fixed!