Omniscience and decision-making

Last week I came to the end of a wonderful student teaching experience. It was a hectic time, but very fulfilling. I might go into more details later, but for now I’d just like to let everyone know I’m back, and that I hope to resume a regular blogging schedule.

In this post, I’d like to say something about omniscience, and how this meddles with the Christian idea of free will. The typical Christian view of free will posits that people can make truly original decisions: decisions that are not determined by circumstances in the real world, but which originate with some “first cause” within the person making the decision. (Suffice it to say that the evidence does not support the existence of this type of free will.)

Unfortunately for the Christian, free will conflicts with another tenet of theology: omniscience. Many Christians believe that God sees the future, that he knows every decision we are going to make.

To see how this affects free will, let me first lay down exactly what I mean by the word “decision”. Let us say that I need to make a choice between two options (for instance, I’ve been accepted into two colleges, and I need to decide which one I want to go to). Let’s call the two options A and B. Before I make the decision, there is a probability associated with each option. Let’s say the probability of me selecting option A is 60%, while the probability of me selecting option B is 40%.  Put differently, the probability of A becoming true at some time in the future is 60%, while the probability of B becoming true in the future is 40%.

As soon as I’ve made my decision, the probabilities change. Let’s say I picked option A. In this case, the probability that A will happen some time in the future jumps to, say 99.99%, while the probability that option B will happen some time in the future drops to 0.01%. In the real world, there are always potential obstacles that could prevent my intentions from being realized. For instance, there is always a tiny chance that I’ll be hit by a bus before I get to go to college. For this reason, the probability of option A happening in the future is not exactly 100% after my decision, but something slightly less than that.

What a decision is, then, is a change in probabilities among choices. More specifically, it is a change that gives one option a far greater probability of occurring than all the others.

Let me also be clear about the timeline involved here. Let us say that at some time t1, I have not made the choice between A and B, and their probabilities are still 60% and 40% respectively. Perhaps t1 occurs on a Monday morning in December, for the sake of argument. At some later time t2, I’ve made the decision. So, for instance, on the following Tuesday morning, I’ve finally decided which college to attend. We can say, then, that my decision took place at some moment between times t1 and t2. 

So far, I hope you will all agree that this is all pretty uncontroversial. I’m simply trying to be more formal in my description of decision-making.

Now let’s suppose that at some time t0 that occurs before t1 and t2, the Christian god has knowledge that I will choose option A. It’s not that God is going to make the decision for me, it’s just that he knows what decision I’ll be making. However, if he knows at time t0 that I’ll soon be picking option A, then we must conclude that, at time t0, the probability of option A occurring in the future is already 99.99%. Indeed, as soon as God’s knowledge came into being – as soon as he found out I’d be choosing option A  – the probability of A occurring in the future would have been known to be 99.99%.  

And this might have been a very long time ago. Let’s say, for the sake of argument, that God knew even at the very moment the universe was created, that I would one day be born, reach college age, be faced with the choice between option A and B, and choose option A. This means that billions of years ago (assuming we accept the scientifically established age of the universe), the probability of option A happening was already known (only by God of course) to be 99.99%.

What does this have to do with free will? It shows that my initial probabilities for options A and B, i.e. 60% and 40%, were not actually correct. It may have felt as if I were choosing between two options with those probabilities, but God actually knew better: he knew that the probability of A occurring was actually 99.99%, because he knew that that is what I would, in fact, choose. What this means, then, is that I didn’t really make a decision at all, because I was not responsible for changing the probabilities of A and B. Instead, I was simply playing my part in what was a foregone conclusion – a conclusion that was already known to God billions of years before. 

So when was the decision to pick option A made? And who made this decision? Under the Christian worldview, it seems reasonable to conclude that God himself made the decision for me to pick option A. If God was not responsible, then the Christian’s only recourse is determinism, i.e. that the laws of physics led inexorably to a situation in which a particular material human brain produced a certain set of electrical impulses encoding the selection  of option A over option B. As to when God made the decision for me to select option A, that is anyone’s guess!

To summarize, if God knows that I’m going to select option A, then when the time comes for me to select it, I’m not really exercising free will, I’m simply doing what needs to be done in order for the long expected event of option A to become a reality.

Ah, you might object, what if I changed my mind at the last minute, and selected option B instead? Wouldn’t that change things? Not really. If I’m going to change my mind at the last minute, and select option B, then you can rest assured that God, in his omniscience knew, even at the dawn of creation, that this is exactly what I’d do. He knew that I would have a choice between option A and option B, he knew that I’d have a crisis of free will and try to change my mind at the last minute, and he knew that I would pick option B as a result of that last minute change of mind. 

There is no way of escaping omniscience.

We must conclude, then, that either omniscience is true, free will is true, or neither are true (my preferred option). We cannot, however, conclude that both are true.


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