It is often argued that if the block universe theory of time is correct then people lack free will. The reason for this contention is because on a B-theory of time, future events already exist and so a person has already made future choices and that these future choices can never be changed. In other words, since the future of a person is already laid out and accomplished, a person cannot do anything other than what she does in the future.
The problem with this argument is that it commits a common fallacy in modal logic: it wrongly identifies any kind of “unchangeable” truth or fact with necessary, non-contingent truth. To identify the fallacy in the argument it is important to know the proper meanings and distinctions between “contingent” and “necessary” truths.
The modal distinction between contingent and necessary truths is not, contrary to Aristotle, the difference between “changeable” and “unchangeable” truths. Contingent truths are just as unchangeable as necessary truths. Sound far-fetched? Think about something that has happened in the past. Let’s say the person Jill has bought ice cream yesterday. Now Jill cannot change the fact that she went to the store and bought some ice cream but it is also true that she could have decided not to buy any ice cream yesterday. So long as Jill could have refrained from buying the ice cream at that event, then she was free to act in anyway at that period of time.
So an unchangeable truth like Jill buying ice cream yesterday cannot be a necessary truth like “2+2=4” or “a triangle has three sides”. And if Aristotle were correct in saying that all unchangeable truths are necessary truths then any kind of reconciliation of divine omniscience of the future and human free will would be doomed to fail whether one advocates a presentist theory of time or a block time theory.
It’s also worth noting that one of the reasons why Aristotle held the idea that propositions about future human actions are neither true nor false in his answer to the logical fatalists of his time, is because in his system, “necessary truth” meant “unchangeable truth”. So if he were to say, for instance, that there will in fact be a sea battle tomorrow it would indicate to him that people absolutely had to engage in a sea battle because once you have an unchangeable truth about the future established then you also have a necessary truth about the future according to his system. But thanks to developments in logic rooted in later medieval philosophers like Duns Scotus and William of Ockham, we know that the distinction between contingent and necessary truths cannot be the difference between changeable and unchangeable truths.
The real difference between contingent and necessary truths lies in this: contingent truths are true propositions that happen to be true but could have been false, whereas necessary truths are true propositions that absolutely have to be true and cannot be conceivably false. For instance, the proposition that “Jill buys ice cream on October 31st, 2018” is clearly a contingent truth because while it is unchangeably true, it could have been false provided that Jill decided to do something else on that day. The mathematical proposition “2+2=4” is a necessary or non-contingent truth meaning that this particular content has to be true and cannot ever be false because it is impossible to add 2 onto 2 and have it equal anything other than 4.
All that the B-theorist has to do to show that we have free will is to point out that facts and truths about the future are essentially contingent facts particularly when we consider human behavior. And by “free will” I am assuming, of course, the libertarian concept of human freedom where a person has several choices she can make as such and that the individual alone determines for herself what choice is made as such.
So if it is true, for instance, that Jill will rob a bank thirteen years into the future from our relative present, then while that future event may already be happening in its respective time and place, it is nonetheless a contingent state of affairs. Now it is true, that Jill cannot change her future event of robbing the bank because once Jill makes that decision within the relative future, it cannot be changed or erased just like once something is done within the past, it cannot be erased. However, Jill could have decided not to rob the bank in that particular event in time; and the fact that she could have refrained from committing theft is sufficient for her to be able to act with free will. In other words, the block time theory is compatible with contingent facts and truths in the world and the time theory does not imply the Spinozian view of necessitarianism (the idea that only necessary facts and truths exist). For that matter, an unchangeable future whether on a static theory or dynamic theory of time, does not imply necessitarianism.
As a matter of fact, the B-theory of time is not the only time theory that entails that the future is unchangeable. Presentists, growing block theorists, shrinking block theorists and moving spotlight theorists can all agree that the future is unchangeable. For it is impossible, as many philosophers point out, to bring about that a future event will not occur because if a future event ended up not occurring then it would not be a future event at all. Hence, whatever will happen, will happen and this is impossible to change or erase. It is literally nonsense to change the future.
Even on an Aristotelian view of time, it would be impossible to change the future. This is because on Aristotle’s view where the Law of Excluded Middle does not apply to the future, there is not even an established future about human behavior to change in the first place. So it is simply a non-sequitur fallacy to argue that from our inability to change the future to the conclusion that people lack free will.
It also equally a non-sequitur to argue that since on a B-theory of time, future moments exist, that there is only one conceivable future that people have to follow as such. What is only implied by an eternalist theory of time is that only one possible future among many possible futures is actualized on the block universe. To argue that an existent, actualized future entails only one possible, non-contingent future is like arguing that since the past consists in a series of actualized events that there was only one possible, non-contingent past or a line of events that necessarily had to take place. Such reasoning is clearly specious and wrong.
Therefore, the block universe theory of time in no way implies fatalism or some sort of nonsensical predestinarianism like Calvinism. The B-theory of time is perfectly compatible with libertarian free will. The contention that the B-theory of time implies fatalism or a denial of free will is nothing but nonsensical hype that is groundless.
Now many religious believers would be, of course, interested in seeing how the B-theory of time would influence one’s views of divine foreknowledge and human freedom. A lot can said about this issue of foreknowledge and free will and unfortunately not every aspect of this issue can be covered within a brief article. However, I will simply say this: I find no logical incoherency in the idea of someone knowing the outcome of future events and persons acting with free will whether one is assuming a block time theory, or a presentist theory or any other time theory. Modal logic can sufficiently show that there is no logical incompatibility between a mind knowing the outcome of future events and individuals having free will.
However, the B-theory of time does offer at least one advantage over any dynamic theory of time that says that the future does not currently exist. The block time theory, because it affirms the existence of the future, it better secures God’s knowledge of the future. The philosophical problem with advocating a presentist theory or a growing block theory for resolving the omniscience and free will puzzle, is how God can know what will happen in the future if the future events do not yet exist and at the same time, persons can make several possible choices with their free will?
Moreover, on a presentist model and a growing block model, God would clearly be temporal which may make it more difficult to account for God’s knowledge of future free choices. If it is true, for instance, that thirteen years from now, Jill will rob a bank, and a presentist theory is true, then God would literally have to wait for thirteen years, causing new present moments to exist one after another before the future event comes to his view. And how is God going to know for certain that Jill will freely choose to rob the bank if it’s possible that she could refrain from performing the action and the future event has not yet occurred?
With a block time theory, if it’s true that thirteen years from now, Jill will steal money from a bank, then God would not have to wait for thirteen years for the event to occur. With a B-theory of time, God would already have the event before his view and there would be no question at all whether Jill freely chose to rob a bank thirteen years ahead of our earlier moment in the block timeline.
So the B-theory of time gets rid of this problem of how God can know future free choices by holding that the future already exists before God. Of course, I suppose I cannot absolutely prove that a temporal God on a presentist theory of time cannot know future free decisions. Nonetheless, being a B-theorist, I conveniently don’t have to worry about how God can know future free choices because of how the static theory of time presents all temporal events before God. At any rate, like with other theories of time, there is no logical incompatibility with the static theory of time and persons acting out of free will.