Some people have suggested that the block universe model is incompatible with any notion of freewill. This is because, they would say, that the future appears to be set-in-stone in the block universe model and thus, we are never at liberty to change it by our choices. However, this is a misunderstanding of both freewill and the implications of the block universe. The misunderstanding arises because the notion of freewill is so poorly defined. We all think we know what “freewill” is, we have a feeling, but it is very hard to write down what the phrase actually means and implies. In the absence of a wholly satisfactory definition, I am going to define freewill as the ability to make decisions, a fairly unremarkable definition but nonetheless, apt.
This definition of freewill is completely compatible with the block universe model. The key thing is that only one course of action results when we make a decision. There is only one outcome. There is only ever one stream of events. For example, the sequence of events when we come to a fork in the road might be:
EVENT 1) You walk along the road and come to a fork in the road.
EVENT 2) You decide to turn to the left.
EVENT 3) You continue your journey along the left road.
This is just a sequence of three events, and that is all the block universe is: a sequence of successive events. So these three events can easily be incorporated into the block universe model.
In the block universe model, events are unchanging and “frozen-in-time”. But that does not mean that those events do not represent the expression of freewill. For instance, when we look back into the past, we consider those past events to be “frozen”, and nothing could change those events. However, we might also remember some of those past events as representing moments when we made decisions, i.e. expressed our freewill. So the notion of freewill is in no way incompatible with the block universe “frozen-in-time” representation of unalterable events.
We are free because, unlike a rock, we do many different things given the same context. And we have a will because our decisions are the product of an internal process guided by the complexity of our minds. Freewill is not an illusion: it is a fact that comes about because of our complexity.
Contributed by Shane Dunne