What is free will?
Merriam-Webster provides two definitions:
1. voluntary choice or decision
2. freedom of humans to make choices that are not determined by prior causes or by divine interventionMerriam-Webster online dictionary (https://www.merriam-webster.com/dictionary/freewill)
In other words, free will is the ability, in each moment, to exercise conscious control over our thoughts and actions, and to choose, as a conscious and deliberate agent, between two or more different choices.
Note that our control over our thoughts and actions must be conscious. There’s no difference, in relation to free will, whether our thoughts are controlled subconsciously by the inner workings of our own minds, or by some computer simulation we may or may not be a part of: both are equally foreign to our intentions as conscious agents, and we have as little control over the former as we do the latter.
So, are we free to choose our own thoughts, moment to moment?
Well, we certainly feel like are — each time a thought arises in consciousness, we feel responsible for it, as though we had thought it intentionally, and often we can even reason about why we did so.
But the idea that we can consciously decide what we’re going to think next, before the thought itself arises, is in fact a logical contradiction, for it would mean thinking about the thought before we actually thought it. At the instant we become aware of a particular thought, the thinking has already been done. How could we have consciously produced that thought before we were even aware of it?
Given the choice between A and B, we can deliberate about the decision for as long as we want, exercising our apparent free will as forcefully as possible. When we finally choose A, we can even reason that we did so intentionally because we remembered that we chose B last time, and this made you want to choose differently this time.
But at the very instant you become aware, consciously, of your decision to choose A, the decision has in fact already been made. Our reasoning about why we made a particular choice, and our feeling of having done so intentionally, is in fact a retrospective on the decision making process, the details of which were played out subconsciously and influenced by countless factors of which we are unaware.
In support of the idea that free will is an illusion, scientists have been able to show that there is a significant time lag between when a decision has been made in the brain, and when the conscious subject actually becomes aware of the decision. At the instant the subject reports having made a decision, scientist have shown through neurological imaging that the decision had already been made in the brain, subconsciously, some hundreds of milliseconds prior.
This completely separates the decision making process from any conscious agency and shows that what we think of as free will is a retrospective illusion. In fact, the illusion of free will is itself an illusion, since it only takes close inspection of our thought process to dispel it, and the illusion only persists due to our lack of introspection.