Free will is yet another of those Big Question philosophical issues that has been pondered and debated since written records have been kept - and probably orally debated well before that. It's one of those topics that has nearly all the evidence arguing against free will and all of personal experiences arguing for free will. If there were ever a concept that you would bet the family farm on, it is that you have free will. Yet in theology, if God is all-knowing, then you can't have free will since God already knows what you will do from here on out. If you are a simulated virtual reality being you can't have free will since the software rules your roost.
Perhaps I'd better start by defining free will. "Free Will: The ways and means of making a personal decision / choice between two or more mutually exclusive options, totally free of any external or internal factors beyond your control." Comment: Of course there will always be external and internal factors beyond your control. You can't ever be free of them so that makes free will a rather moot prospect. For example, you might be right-handed and thus always signal for your taxi with your right arm. Further, my definition says absolutely nothing about decisions being informed, rational or moral.
You cannot have free will in a deterministic clockwork Cosmos. You cannot have free will even in a Cosmos that has quantum mechanics and randomness / probability at the core of reality. That's because your decisions are ultimately then based on randomness / probability and so you still aren't in control.
Speaking of control, 1) there is no free will exhibited when it comes to obsessive compulsive behavioural disorders. 2) When your brain is exposed and you are consciousness, neuroscientists can stimulate / touch / manipulate parts of your brain causing you various bodily reactions and you are helpless to prevent these reactions from happening even though you are consciousness. 3) You apparently have no free will under hypnosis. 4) You've forgotten 99.999% of all you have ever experienced and not even your pure free will to remember something will guarantee that free will decision will come to pass. 5) Then too there is brain washing, being subjected to perform an involuntary action when given a subconscious stimulus. "The Manchurian Candidate" is a novel / film based on this well-established concept. 6) You have no free will over seeing an optical illusion's illusion even though you are 100% aware that you are seeing an illusion.
You can't identify any structure in the brain that is your centre of free will, which if manipulated can influence even change your decisions. Where is your free will actually located? Perhaps the illusion of free will is locked up in the computer software that actually simulates your 'existence' in a virtual reality landscape. This is the essence of the Simulation Hypothesis.
There are two main versions. There's the "puppet on a string" scenario, akin to a video game where you are the puppeteer and the characters in the game are the puppets. Then there is the "cast your fate to the wind" scenario, where the programmer just sets out all of the initial parameters, hits "enter" and sits back and watches what unfolds according to the programmed laws, principles and relationships encoded into the software. This is a common scenario in many of our "what if" number-crunching research programs; modelling say climate change or economic outcomes.
Okay, with the basics out of the way let's explore the free will issue in the context of the Simulation Hypothesis.
The Video Game Analogy
# If you really had free will, and if you really designed your own video game or simulation, would the characters in that game or simulation have free will? Highly unlikely. Now just go up one level. The Simulators might have free will, but their simulated characters (that's us) don't have free will - that old "puppet on a string" scenario.
# Do the characters in our video games actually think? They appear to think. They appear to have consciousness and personality. They - our video game characters - act or behave in such a way as to simulate as far as we are concerned their ability to see, hear, etc. That's partly what simulations are about. They simulate what we expect them to experience.
The Free Will Illusion and Virtual Reality
# Now while software might not be able to simulate free will, it can certainly encode the illusion of free will. The easiest person in the world to fool is yourself, and the brain's software gives you a big assist along that path. Your brain's software, or the programmed software that controls your simulation, gives you the illusion of phantom limbs for example. Optical illusions are well known, and your apparent free will just cannot override those illusions even when you know they are illusions. There are also auditory and tactile illusions. Many of your memories have illusionary components. I'm sure that if you could somehow ask the characters in our video games whether or not they had free will they would answer "of course". Maybe one day if consciousness can be encoded as computer software, we could hold such a conversation.
# In the Simulation Hypothesis we don't actually think original thoughts or have free will - there's no choices to be made; no decisions to be had. We don't think of all possibilities, or all variables. We react, even if we react to what we think we're thinking. What you think you think is all pre-programmed software. Recall the "cast your fate to the wind" scenario. The characters in our video games don't think. They react to the software that's directing their actions. That again is the old "puppet on a string" scenario.
# You may think that you think, but that could be all in the programming. If you could somehow wander the corridors of your own brain could you actually find your free will, your essence, your self-identity, your self-awareness, your consciousness, your personality, your creativity, your 'the you' that you assume you are, your 'myself'? Sorry, all of that is nowhere to be found. If scientists like Susan Blackmore are correct, 'the you' doesn't actually exist. 'The you' is actually just an interconnection of neurons, genes and memes. I could postulate however that they - these nowhere to be found mental bits - are programmed / simulated.
# Since we are programmed in either a "'what if' cast your fate to the wind" scenario or a "puppet on a string" scenario, we're not about to get into things that we weren't programmed to get into. That's not to say that The Simulators, the Supreme Programmer(s) wouldn't tweak or upgrade their software*, just not in response to anything attributable to what you might term 'free will' on our part. They couldn't respond to our 'free will' if we weren't programmed to have 'free will' in the first place. More likely as not it would be impossible even for them to program us as virtual beings with 'free will'.
# Which leads to the following observation. If we could somehow create an artificial intelligence or simulated beings with actual awareness, consciousness, the ability to think and also with free will abilities or decision making prowess, then by implication The Simulators could have endowed us with consciousness and free will. However, then it would seem that The Simulators have lost all control over their simulation. ["Colossus: The Forbin Project" anyone?] However, the positive is that their creation would be a heck of a lot more interesting and stimulating and entertaining.
I Have Free Will Therefore I'm Not Virtual Reality
# Lets go however with the probability that it is nearly impossible to create virtual reality characters that can actually have independent autonomy and free will. Now to my mind the only valid objection against the Simulation Hypothesis is the "I have free will" argument. That said, if you adopt that point of view, all you need to do is prove to the satisfaction of the rest of the world that you actually have free will, and therefore by extension all humans have free will. Then I will concede that the Simulation Hypothesis is as close to impossible as makes no odds and I can put my time, efforts and energy to better use than pondering over our possible virtual reality.
# Somewhere on up the chain there has to be a really real reality with really real beings who have free will to create, or not create, computer simulations. The Simulators at the apex would indeed have free will although their simulations, or simulated characters (like us) do not. I've said it before and I'll say it again, if you can prove to the satisfaction of the rest of the world that you have free will, and the rest of the world agrees, then all of the people who are in the Doubting Thomas camp can now change their Doubting Thomas spots. Then I'll gladly throw the Simulation Hypothesis in the rubbish bin and get on with more productive things. For now it's over to you!
# Of course, even without conclusive proof of the reality of free will, anyone and everyone can absolutely and firmly believe that they indeed have free will and that free will isn't an illusion, programmed or otherwise. Then you would place your bets on our being really real beings in a really real reality. For the here and now at least, I don't happen to share that belief.
# In any event, what does it really matter whether or not you are composed of electrons / quarks or bits / bytes? It doesn't alter any of your achievements or for that matter any facet in and of your existence. Of course it might make a difference when you depart this mortal coil, but that's another issue.
Now my alternative theory, assuming a really real reality instead of a virtual reality is that there is a part of your brain that ultimately controls your 'Free Will'. It's your brain's "pleasure centre". On the grounds that you will always tend to maximize pleasure and minimize pain (or unpleasant things), when you make a "free will" decision it is going to be a decision that will provide maximum pleasure or at least minimize displeasure, to your brain's "pleasure centre". So if pizza is a more pleasurable option for lunch than steak, you'll decide for pizza. If the electric chair is a lesser unpleasant option than hanging, (assuming you have a choice), you'll opt for the electric chair. No two options are ever going to be absolutely equal in terms of giving you the most pleasure, and thus your "free will" opts for whatever will give you the most pleasure (or least unpleasantness). That's my alternative working hypothesis anyway.
*If we dig a hole, presumably their software has dictated even determined that "what if" possibility of there being treasure at the end of the 'tunnel 'and they react to that intention by us to start digging and so then simulate the buried treasure awaiting to be found. It could even be just all before-the-fact - the digging was programmed in before-the-fact; the buried treasure was programmed in before-the-fact. Further, what makes anyone think that The Simulators have to be actually watching their virtual reality creation(s) 100% of the time in order to tweak or upgrade their software as required? They, being the advanced beings that they are, could have automated routines programmed in to alert them to some kind of unfolding scenario that requires their attention, which again is probably not going to be the case since we've not been programmed to have actual free will and thus force their hand with our out of control free will antics.