Confused? Well, you have every right to be.
To save myself typing here's the introductory section of the Wikpedia page on Free Will, which will do for my current purpose:
The question of Free Will is whether, and in what sense, rational agents exercise control over their actions and decisions. Addressing this question requires understanding the relationship between freedom and cause, and determining whether the laws of nature are causally deterministic. The various philosophicaldeterminism versus indeterminism—and also on whether freedom can coexist with determinism or not—compatibilism versus incompatibilism. So, for instance, hard determinists argue that the universe is deterministic, and that this makes free will impossible. positions taken differ on whether all events are determined or not—
The principle of free will has religious, ethical, and scientific implications. For example, in the religious realm, free will may imply that an omnipotent divinity does not assert its power over individual will and choices. In ethics, it may imply that individuals can be held morally accountable for their actions. In the scientific realm, it may imply that the actions of the body, including the brain and the mind, are not wholly determined by physical causality. The question of free will has been a central issue since the beginning of philosophical thought.
A cornucopia of 'isms'...
There are some scientific observations indicating that Free Will may be illusory; that we do act as if we had it, and that we by and large judge the actions of others as if they had it, but that in reality we and they don't. In some specific cases of willed actions it has been shown, and this is quite beyond argument, that the brain activity associated with triggering an action, such as the volition-initiated moving a finger, actually precedes the decision to move it. Meaning that what we think of as a 'decision' really isn't, and that it looks much more like our apparently conscious 'decision', "Should I move this finger or not? Yes, lets!", is more like a 'reporting' of a decision made at what would commonly be called a 'subconscious' level, which is beyond our actual control and, one would reasonably argue, makes a mockery of the notion that we 'choose' our actions as 'rational agents'. It may also be argued, equally reasonably, that these 'subconscious' processes are instances of determinism. Never mind that they are very complex. If one knew all the parameters involved in creating them, one would be likely to find that, yes, there's a perfectly sensible chain of, very complex, causation that leads to them being initiated, and that chain has nothing to do with the agent making 'Free Will' decisions.The experiments I alluded to above, plus a vast supporting cast of related data, have been used by many to question the whole notion of Free Will, as well as such concepts as 'moral responsibility' and so on. If people really can't make rational decisions about what to do, if this 'rationality'--the capacity to reason, starting from whatever premises one cares to start from, with subsequent decision making based on whatever the process of reasoning led to--is just a smokescreen, or at best a reporting system for making explicit the results of processes that are beyond the reach of reason and out of our control, then 'responsibility' pretty much goes out the window. Any psycho, and especially if he's a 'psycho', would rightly argue that whatever he did was out of his control and how dare anybody even consider wanting to, for example, mete out punishment or exact revenge. You can see where this leads.
Don't dismiss this as poppycock and piffle, because you happen to find this inconvenient and/or unpleasant to ponder. It's a serious issue, and it cannot be dismissed with the wave of the that's-obviously-nonsense hand.
This is, we are in many ways...let's call it 'guided' in our decisions by what has gone before; by the events and influences that have led us to this particular place in our lives and circumstances. If we weren't who we are, we wouldn't make the decisions we make, whether those 'decisions' be rational and conscious or pre-conscious, with consciousness merely acting as a, if you will, 'rationalizer'. And, yes, if you look at human behavior from a certain angle, you'll soon notice that, when it comes to behavior, the line between 'reasoning' (pre-decision/action) and 'rationalizing' (post-decision/action) is very blurred indeed; if for no other reason but that everything he 'think' is subject to the delays built into our biological neural networks. Indeed, I'd go so far as to say that all explanation of human behavior, and especially that relating to our own, is in effect 'rationalizing'--as is a lot of that which goes on before action takes place; if for no other reason but that the 'rationalization' is actually a post-decision thing, only that said decision might not, at the time we're doing the rationalizing, have led to discernible 'action' as yet.
And yes--in case you've caught onto this--this also very much calls into question the whole distinction between 'thought' and 'action', which seems to become quite meaningless in this context.
'Free' Will is, I think, a canard. Nobody has ever made a decision that could be considered 'free' from constraints on the decision making process--not even if we disregarded the whole issue of neural pre-conscious-decision readiness-potentials. But within the constraints, might there not be some room to move? To say "yes" or "no" to moving the finger that pulls the trigger that shoots the gun that kills another human being? To say "yes" or "no" based on factors that are under our control?
The problem here is that we really need to define who this 'we' is that things are supposed to be controlled by--to some degree anyway? Are we talking about the 'rational agent'? Is there such a thing? Haven't we had that very notion called into question with the experiments I was referring to, where the 'rational agent' is replaced by the 'rationalizing reporter'?
Another problem--yeah, I know; problems, problems, but where are the solutions?--is that it is unclear just what exactly is the 'point of decision'. It would be nice if it could be pinpointed with fair accuracy, like saying "this is where you decide(d)", but in fact one can't. The closer one probes, the harder the determination becomes, almost as if a kind of uncertainty principle prevailed here, too. In physics the principle relates to the simultaneous determination of a particle's position and momentum: the closer you determine one of the two, the more uncertain becomes the other. That's because the observation of one--by whatever means you care to select--involves a technique which will effectively destroy information about the other. I'm still trying to work out which are the two equivalent parameters in the cognitive domain, be it conceptual or the physical equivalents.
Our inability to get a handle on what a 'decision' is, in neurological terms as well as cognitively speaking, makes the whole thing almost impossible to sort out.
There's also the fact that all these readiness-potential studies were done with very short-term processes, which encourage pre-cognitive acts. But what about 'long term' decision making? Like us deciding that we're going to move to Australia? That may have been short-term relative to some people's decision-making processes; but, let's face it, it was something definitely outside the range of your average readiness-potential study.
So, what about long-term decisions? If I decide today that tomorrow I will go to the movies, the actions involved are quite a long way off to being implemented. And what if I change my mind, merely because I decide a bit later that I didn't want to see that particular movie after all?
Questions, questions, with near-limitless potential for dialectic obfuscation and no end to the discussion in sight.
As for the various options shown on the diagram at the beginning, I am tentatively in the Compatibilism camp. It seems like the place with the greatest match to what we 'know', scientifically speaking.
Still, who knows what's 'true' and what isn't. And, as far as everyday life is concerned, let's go with the philosophy of, T'sais, one of my favorite Jack Vance short stories from the Dying Earth collection.
In the tale a witch cast a spell upon Etarr and T'sais, compelling them to become automatons, doing her bidding and only her bidding. Alas, T'sais was wearing a rune which deflected the spell, thus not only protecting herself, but also bouncing the spell back onto the witch. But Etarr had been ensorceled and could only do as he was told, including answering specific questions, but unable to supply unsolicited information.
T'sais broke the spell on Etarr by ordering him to act at all times as Etarr would have acted had he not been bewitched. In this way the spell was anulled.
The same goes for us and Free Will. There is nothing wrong with acting at all times as if we had it. At the worst it'll make no difference, but we'll never actually know, so it doesn't matter. It's like the randomness vs. hidden-variables debate. If you can't ever find out what is true, then you might as well act as if it were--or not, depending on how you decide (or have things predetermined, in which case you're not deciding anything, but you won't know that and...).
Acting under the assumption that we do have Free Will, however, will, by and large, make us feel better about ourselves; for thinking of oneself as slaves to fate, or some f...d-up deity for that matter, is just as bad for one's mental health and good-feeling as being enslaved in the more conventional sense.