The word "deterministic" is correct in some sense: there are only laws of nature, no magic. But it brings some incorrect connotations. In a usual discussion the possibilities are framed like this:
a) The universe is a big machine with a lot of wheels. The wheels are rotating, and this is all there is and ever will be.
b) The universe is a big playground of dice, randomly rolling. There is nothing to know about the dice, except that they have some statistical properties.
Of course the choices are usually not expressed this way, but I tried to emphasise the emotions behind them. Essentially, both these pictures seem stupid and give no clue how anything non-trivial could happen in such world. Asking whether the world is deterministic is like saying "pick one of these two models". A wannabe smart person could argue that the first model is compatible with classical physics and the second model with (some intrepretations of) quantum physics.
In my opinion this dilemma is completely irrelevant to discussions about consciousness, free will, etc. The true nature of the universe at the micro level is not necessarily relevant for its macro-level events. A complex pseudo-random generator can be built from perfectly deterministic parts. A huge amount of random events can create a fairly predictable Gaussian curve. So the lawfulness or randomness on human level does not trivially follow the lawfulness or randomness of the elementary particles.
The interesting part is how are the complex things constructed from the small things, because some properties appear and others disappear in the process of construction. Magnetically charged particles create a magnetically neutral atom. Atoms join and make molekules; and depending on the structure and energy of the molecules we have gas, liquid or solid stuff on the macro-level. A macro-level structure of X-es can behave differently than X behaves on the micro level. But this is no magic; it's just a consequence of mathematical laws, although such consequences can be hard to guess.
There are two theoretical sources of (perceived) randomness. 1) Due to laws of thermodynamics our mind can never be perfectly synchronized with the rest of the universe, because we are part of the universe and by doing anything (this includes observing and learnining) we inevitably change it. 2) According to the many-worlds interpretation our universe is constantly splitting into many branches and our copies don't initially know which branch they are in.
But I think that these theoretical limits are irrelevant for everyday life; our typical ignorance is many levels higher than the quantum or thermodynamic effects. We don't know most things simply because we don't observe much and don't remember much, because we are very limited by the structure of our bodies.
I'm participating in a university course on free will. On the online forum, someone asked me to summarise Eliezer's solution to the free will problem, and I did it like this. Is it accurate in this form? How should I change it?
“I'll try to summarise Yudkowsky's argument.
As Anneke pointed out, it's kinda difficult to decide what the concept of free will means. How would particles or humans behave differently if they had free will compared to if they didn't? It doesn't seem like our argument is about what we actually expect to see happening.
This is similar to arguing about whether a tree falling in a deserted forest makes any noise. If two people are arguing about this, they probably agree that if we put a microphone in the forest, it would pick up vibrations. And they also agree that no-one is having the sense experience of hearing the tree fall. So they're arguing over what 'sound' means. Yudkowsky proposes a psychological reason why people may have that particular confusion, based on how human brains work.
So with respect to free will, we can instead ask the question, “Why would humans feel like they have free will?” If we can answer this well enough, then hopefully we can dissolve the original question.
It feels like I choose between some of my possible futures. I can imagine waking up tomorrow and going to my Engineering lecture, or staying in my room and using Facebook. Both of those imaginings feel equally 'possible'.
Humans execute a decision making algorithm which is fairly similar to the following one.
List all your possible actions. For my lecture example, that was “Go to lecture” and “Stay home.”
Predict the state of the universe after pretending that you will take each possible action. We end up with “Buck has learnt stuff but not Facebooked” and “Buck has not learnt stuff but has Facebooked.”
Decide which is your favourite outcome. In this case, I'd rather have learnt stuff. So that's option 2.
Execute the action associated with the best outcome. In this case, I'd go to my lecture.
Note that the above algorithm can be made more complex and powerful, for example by incorporating probability and quantifying your preferences as a utility function.
As humans, our brains need the capacity to pretend that we could choose different things, so that we can imagine the outcomes, and pick effectively. The way our brain implements this is by considering those possible worlds which we could reach through our choices, and by treating them as possible.
So now we have a fairly convincing explanation of why it would feel like we have free will, or the ability to choose between various actions: it's how our decision making algorithm feels from the inside.”