Do we have free will? Before we can answer that question, we first have to define what the term means. So, what does it means to say that we have free will? According to some people, free will means being able to do what one wants to do. In that case, one would lack free will only insofar as one couldn’t do what one wanted.
For example, I would be free with respect to my desire to eat the fruit on the tree so long as there wasn’t anything stopping me from doing so (such as my being locked in jail, unable to reach the tree outside). On this understanding of freedom, I would be free regardless of whether it was against the law to eat the fruit, and regardless of whether I would be punished for so eating.
But suppose the only reason I want to eat the fruit is because a witch has cast a spell on me (or a mad scientist is using a mind-control device, or Dracula has hypnotized me, etc.) to make me desire the fruit. Would I still be free? Clearly not. It’s obvious (to me, anyways) that if someone or something else is causing me to make the choices I make, then I am not free with respect to those choices. But according to this definition, I would be. This shows that free will is not just a matter of being able to do what one wants. Hence, we must revise our definition.
Another way we might define it is as follows: free will is the ability to do otherwise. What is the ability to do otherwise? It means one didn’t have to do the action – one could have refrained from doing it, or could have done something different. In that case, one’s action or choice would not be free insofar as one necessarily had to do it, and couldn’t possibly not do it.
This is what Alvin Plantinga has in mind when he says “If a person is free with respect to a given action, then he is free to perform that action and free to refrain from performing it” (God, Freedom, and Evil, page 29).
For instance, I would be free with respect to my choice to eat the fruit on the tree so long as I can choose to eat the fruit, and choose not to. So if I were caused to eat the fruit by a witch who cast a spell on me (mad scientist, Dracula, etc.), then I would not have been free with respect to that action, because it would not have been within my power to not eat the fruit.
Notice that on this understanding of freedom, I would be free regardless of whether anyone knew that I was going to eat the fruit. If someone knows that I will do some action (has foreknowledge with respect to my doing that action), then I will in fact do it. So, doesn’t this mean I couldn’t do otherwise with regard to eating the fruit? No. It means I will do it, not that I had to. The person who knows what I will do is not causing me to do it. If it’s my free choice to eat it, then I could also have refrained from eating the fruit, in which case any person who had believed that I was going to eat it would simply have been mistaken.
But, suppose there is someone who knows everything (and thus can’t be wrong), and furthermore, suppose this person knows that I’m going to eat the fruit. In that case, would it follow that I couldn’t do otherwise? No. All that would follow is that, had I refrained from eating the fruit, then that person would have known that I was not going to eat it.
Hence, we can be free even if someone (such as God) knows everything we will choose. What God knows does not determine what is true; rather, what is true determines what God knows. Likewise, what God knows does not determine what we will freely choose; rather, what we will freely choose determines what God knows (with respect to those choices).
So, if we have free will, this implies that things didn’t necessarily have to happen the way they did (and don’t necessarily have to happen the way they will), that there is more than one possible series of events, more than one possible outcome. This means that determinism, the view that there is only one possible series of events, must be false in order for freedom to be possible.
Is determinism false? Do we have free will? What is the significance of free will with respect to the existence of God? Questions for another post.