Foreknowledge and Free Will

One common objection to Christianity goes like this: if God knows what we’re going to do before we do it, how can we have free will?

Free will is the ability to make a choice oneself, rather than to be determined by someone else to make your choice. Typically, you don’t have free will unless you are actually able to choose between two live options.

Jane’s hamburger dilemma

To make this easier to think about, let’s create a scenario. Let’s say that, on Tuesday, Jane is faced with the choice either to eat a hamburger or a hot dog. Since this is a free choice, she could choose either one. She ends up choosing the hamburger.

But if God knew on Monday that Jane was going to eat hamburgers, how could Jane have free will? When Tuesday rolls around, Jane will have to choose the hamburger, right? Or, if she had free will, then she could choose an option that would make God wrong.

So this makes it seem that God’s foreknowledge is not compatible with free will.

What is knowledge?

However, the argument above makes a basic mistake. That’s because it misunderstands what knowledge is.

What is the relationship between a fact and knowledge of the fact? Simply, the knowledge of the fact is contingent, or dependent, on the fact. The only way that I would know that my son’s hair is blond . . . is that my son’s hair is actually blond. My knowledge is not the source of his hair color; his hair color is the source of my knowledge.

So let’s bring this into the story of Jane’s hamburger, but let’s forget foreknowledge for a bit. On Tuesday, Jane chooses to eat a hamburger, when she could have chosen to eat a hot dog instead. Jane’s coworker Alex sees Jane eat the hamburger, so he knows which one she chose.

Now, does Alex’s knowledge of Jane’s choice mean that Jane couldn’t have eaten a hot dog instead? No. Jane’s choice was free-willed. She could have chosen either one. It’s just that she did choose the hamburger, and so that’s why Alex knows that she did.

Now let’s imagine that Jane chose the hot dog instead. Would Alex know that she ate the hamburger, if Jane in fact ate the hot dog? Of course not. Since Alex’s knowledge is contingent on Jane’s action, Alex will know what Jane eats, whether it is the hot dog or the hamburger.

Alex’s knowledge doesn’t mean that Jane didn’t have free will. It just means that she freely chose the hamburger rather than the hot dog.

What is foreknowledge?

Okay. Now let’s say that Alex walks out of the office this same day, Tuesday, and goes home. On the side, he’s an inventor, and he happens to have just perfected a time machine. He steps in it, twiddles the knobs, and goes back to Monday.

So now, it is Monday, and Alex knows what is going to happen on Tuesday. He knows that Jane is going to eat the hamburger. He has foreknowledge, or knowledge that comes from before the event.

Did something just change with Jane’s choice? Did her choice suddenly stop being free, now that Alex traveled into the past? No. Alex’s foreknowledge isn’t what causes her to eat the hamburger—it’s her own free will. Instead, her choice is the source of Alex’s foreknowledge.

It’s still true that Jane could have chosen the hot dog. But what would have happened if she had chosen the hot dog? Simply, the foreknowledge that Alex carries into the past would be that Jane ate the hot dog.

Now that we’re back to Monday, Jane could be going to choose to eat the hot dog. It’s just that she won’t. If she were going to choose to eat the hot dog, then Alex would know that instead of knowing that she is going to eat the hamburger.

That’s the way God can know future free-willed choices. The choices are the source for his knowledge, not the other way around. If the choices were going to be different, God’s knowledge would therefore be different, because the source of his knowledge would be different.