I actually couldn't link to the other page, but oh well... I want to say my thing on free will.
Wondering on the existence of free will, is something that sometimes induces the more philosophically inclined individual to attempt doing something really dumb just to see if they can get away with it. Almost, say... as an excuse for rebellion? From everything, including what's been done before.
Not to say that this is the whole point of the short story, but Graham Greene's andquot;The Destructorsandquot; deals somewhat with free will, and how we can choose to let the systems that we create fall apart. Its almost easier. Entropy (which I think exists in states of mind, as well as in the mere physical,/biological world.) would have a tendency to tear apart all that is created by human beings. In fact... Entropy would have a tendency to delete life, cancelling the universe with its equivalent amount of antimatter (we're not talking star-trek, here).
But that's not the case... (unless i don't exist

)
So that rules out the (known) laws of the universe being the source of free will because the obvious intent of its will would create a lack of existence for everything. This leaves the mind of the self or the influence of a diety as an influence for one's decisions. (I apologize if my definitions or usage of terms are inadequate, but oh well...)
Sanduleak, I think, already mentioned the idea that people could potentially be acting moving only as the result of chemical synapses. I've thought this through to a great extent
Here's a comparison to the human mind:
Written language is perhaps considered to be one of the greatest inventions (not necessarily discoveries) of mankind. What really takes place with Written language... is the transfer of one idea from the mind of one person to another while putting a suspension on time. E=mc^2 (which I believe is one of the laws of physics, not thermodynamics, but maybe both...) is the (simplified version of the) mathematical equation for the conservation of energy.
So... matter can't be created nor destroyed, but can only be converted from one form to another.
So what happens when you write down the fruits of your thoughts and experiences in a journal which is lost for a thousand years, then someone else reads it and learns from your writing? Information may not be exactly the same as energy, but it requires energy to store information in any form. From my limited collegiate studies of Physics, every real machine or system (as in, not a theorization of ideal conditions) has a great percentage of lost energy.
Similarly... when one person reads something written by another person, they aren't really reading the same thing. They are applying their personal experiences and their backgrounds to this new thing... which has essentially been created in there minds, induced by the written material. Some of the information is lost.
Now, back to the chemical control of your head:
Everything you know (or might care to remember...) is stored in your brain. You experienced it from the translation of chemical to electrical transmissions in your nervous system, originating from your sensing extremities. Your senses allow you to come into contact with the outside world, transferring information from places, things, and people.
So information has been transferred from person to person to person, throughout generations and for all of human existence... And data has been gathered from the world... info about plants and animals and perhaps the weather, eh? Now your various spins have been put on your observations, stemming from the data recieved from other people. Through the transfer, however, some of the data from other people has obviously been lost.
Without original thought... and the loss of information, we would necessitate towards entropy. We would be getting stupider, and not smarter. But, civilization has been building up and the human race as a whole, is getting smarter (in theory... but we may have to exclude the president and a few others...)
If we are cognitive beings, part of this must be sentient and cognitive choice. Our civilization would not be possible without it.
We have to have free will.
Besides... you won't get anywhere if you blame someone else for all your problems. You have to do something.
(Donnie Darko anyone? almost a comforting thought if we're thinking about Armageddon...)