This is a question I've thought about for a long time. Recently, I have concluded that free will does not
I have come to this conclusion primarily by observing my own thought process. It seems to me that I have never once in my entire life willed myself to think something. Almost every thought I have ever had was triggered by the previous thought or by some external stimulus. Sometimes thoughts occur to me randomly out of the blue, but I don't will these thoughts more than any others.
For example: as I am writing this, I happen to glance at a pencil on my desk, which triggers a memory of myself using that pencil this morning to take notes in my archaeology class, which makes me think of my friend Allison because she is also in the class, which reminds me of her friend Sarah who is in my English class, which makes me think of a paper that is due in a few weeks for that class, which makes me think to check when the paper is due. When I see the paper is actually due next Friday, I end up doing some extra reading of the book the paper is on tonight instead surfing E2 for two more hours.
Consider my "decision" to read the book instead of surfing E2. How much of this decision was the result of free will, and how much can be traced back to the pure happenstance of my glancing at the pencil while I was noding? It seems to me that reading was pretty inevitable once I glanced at the pencil, based on the random thoughts that occurred to me and my nature- and nurture-based disposition to be studious and read when I know I have a paper. This example actually happened to me a few days ago, and I don't even remember debating at all - once I saw the due date of the paper, I immediately felt I should read instead of node, and I did.
It seems to me that most of the everyday "decisions" we make are this kind of go-with-the-flow decision. We just do whatever we think to do. How many times have you realized you didn't do something you would have done if only it had occurred to you at the time? Have you ever wondered why it didn't occur to you? How many times have you been writing a paragraph, and you think several sentences ahead, but by the time you get to that sentence, you can't remember the exact words you were thinking of a few minutes before, so you just use a slightly different wording? I just did that now! It seems clear to me that our thoughts and even our words are totally dependent upon our mood, how awake we are, upon what our previous thought was, or upon our perception of something in our environment, but never upon our will. And if we can't even will our own thoughts, can we really will enough to truly decide anything?
"A-ha!" I can hear you responding, "You have only talked about small and inconsequential everyday decisions. What about those big decisions in which we actually do feel unsure, have trouble choosing between two or more partially if not equally attractive options, and utimately pick one and act on it?" Well, to answer, I'm not so sure those are decisions really driven by free will. It goes back to my conviction that we can never will ourselves to think of a certain thought, but rather that every thought we think of is determined by the last thought, or something we perceived, or some random thought that we're not sure where it came from but is just as unwilled.
When we are faced with a big decision, our brain starts thinking about the consequences of different actions we could take. We do not will which consequences we think of, and if we happen to not think of certain consequences, this will affect our decision. It takes a certain perceivable amount of time for our brain to think through all these consequences and possible options, and because we have consciousness - the ability to observe our own thoughts, we percieve this time lag as a decision made by free will.
It seems to me the main way we come to feel we have free will is those times when we feel like we "just can't decide" but finally do decide, for better or worse. We wonder where this decision came from if we really couldn't decide, and conclude that we must have generated it ourselves, through this mysterious thing we call "will." Well, here's a little trick I figured out that will make you question whether you really couldn't decide, or whether your ultimate decision was inevitable all along but you were just experiencing a "time lag" while random, unwilled thoughts about options and consequences were running through your brain - the next time you face a decision where you can't decide between two apparently equally attractive options, assign each option heads or tails, flip a coin, and tell yourself that no matter what, you will do what the coin says. About half the time you will flip the coin and do what it says, but the other half of the time you will flip the coin, think for a minute, and suddenly realize that you actually want to do the other option! Try it and you will see this is true - it's like you had secrectly already decided, but were just in "time lag" thinking about it, and by flipping, you were just forcing the time lag of your thoughts to end sooner, revealing your preordained decision!
Weird stuff, but fun to think about. To conclude, I think the main reason we believe in free will is because it pleases us to do so, and because it would be pretty hard to go about with everyday life if we didn't - who would we blame? Thus, I myself believe in free will for 99% of my life, but when I really stop and think about it, for that 1% of the time I find that it's probably all an illusion.
I'm not a philosopher, I'm just saying in my own words how I see things. Please don't come back at me with confusing terms like "compatibilism" and "soft determinism" - I've never taken philosophy so I don't really know what they mean. Just take this for what it's worth.