There is a common complaint that I’ve heard by more than one free will believer: when asked to think about “if all events are caused (deterministic) and if we could bring back time to some point before a decision was made, could the person have decided differently?”, some people complain that “well we can’t do this”. They note that it is impossible to rewind time or to travel in time to before the decision. They note that we “cannot test this”.
This response, however, is one that misses the point entirely. The point isn’t about whether we can have the ability to “rewind or reset time” or “physically test it”. The point isn’t a claim about time travel, or magical powers over time. Rather, the idea of rewinding time or going back to a point in a time is used as a legit thought experiment, and the only point in the thought experiment is to get the person thinking about the causality and what that means for the decision that was made.
We don’t need to be able to actually rewind time to understand why the thought experiment works for its intended purpose. The purpose of the thought experiment is to show how, prior to the decision or decision process, the outcome could never have been some other decision, if every event in the universe has a cause.
So if the universe is deterministic (indeterminism is different and has its own problems), and you opened the refrigerator door, deliberated on a pepsi, rootbeer, or lemonade, and after a certain amount of deliberation decided on lemonade, the pepsi or rootbeer were never real possibilities in the sense that you could have physically been drinking them instead. Imagining going back to the point prior to the deliberation with the same causal setup, allows us to understand that causality would flow the same way. You would open the refrigerator up the very same way, deliberate the very same way, and finally opt for the lemonade the very same way.
At this point, some might say “but if we cannot rewind time to the point, we cannot test for this. We cannot know that we would decide lemonade if we did rewind time.”
That response, however, assumes that all knowledge needs to be a posteriori knowledge, meaning that we need to be able to observe it to rationally make a conclusion. This is incorrect. We can assess causality deductively (a priori knowledge), and recognize that if one is suggesting that causality can play out differently on “rewind”, a cause that holds self-contradictory characteristics would be required, either that, or a causeless event is being postulated, and we are in the realm of taking about indeterminism (and how any non-caused event cannot help grant free will either). If you are unsure why, pick up a copy of my book and/or check out these other posts:
To put this another way, a cause requires ‘sufficiency’ or what I call “must lead to causality”:
- Why “Must Lead To” Causality is Logically Concluded
- Uncomplicating Necessary and Sufficient Causality (for the Free Will Debate)
In short, if one suggests that the configuration of cause X can both have the characteristics (variables within the structure of X) that lead to effect Y and those same characteristics can not lead to Y (but to Z instead), would mean that those characteristics hold a contradiction. They are thus, the causal structure that lead to Y and also the structure that do not lead to Y, breaking identity of the causal structure.
The only way out of this logical conundrum is to postulate an event that does not have to do with the cause to push to the outcome of one over the other. The only way out is to suggest a non-caused event, and we are no longer in the realm of discussing the scenario that every event has a cause (determinism).
So no, we certainly do not have to really be able to “rewind time” to assess the thought experiment. We just need to understand that, if we are talking about a “rewind scenario while postulating an entirely causal universe”, we can understand what that would entail. First, since we are rewinding a universe to a point in time that already happened, and every event has a cause, the conditions of the universe and physics of the universe would be unchanged (as that would be deterministically dictated by what was already in place prior to the point in time – including the same initial condition). Second, once we have that identical universe state, logic dictates that the next events would causally happen the same way.
This also includes our conscious thoughts and actions which would not fall outside of causality into some magical structure. We’d open that refrigerator door the exact same way, our brains and mental state would be identical, we’d deliberate between the pepsi, rootbeer, and lemonade the exact same way, and we’d choose lemonade the exact same way. Given causal determinism, we could not have chosen the rootbeer or pepsi instead. Given causal determinism we could not have changed our mind and decided on no drink. Given causal determinism we could not have decided not to even open the refrigerator.
And given causal determinism, if we could rewind time to right before we open the refrigerator door, all events will play out identically, each and every time we rewind time to that point….and the only way a change could happen, ever, is if an indeterministic event pops into the mix. As we all know, however, indeterminism is not a free will savior. Nor is the belief in free will something we really want or need anyway:
- Ontic Probability Doesn’t Exist: Assessing “Probability” for the Free Will Debate
- “Realist” Quantum Probability Cannot Grant Free Will
- On The Practical Importance of the Free Will Debate