I don't believe in free will.
There are good reasons for why I feel this way. And given the conditions of the universe at every instant during my lifetime, which encompasses those reasons, it isn't possible for me to believe or feel about free will in any way other than the way I do now.
That's why I don't believe in free will: I understand that I'm part of a whole, as Einstein put it, called "universe."
Dennett's specious arguments in favor of his confused view of this subject -- we're sort of free, sort of not, because we feel we are -- were ably refuted by Daniel Miessler.
Now Sam Harris has done his own refuting of Dennett. Harris' response includes some philosophical geekiness that I didn't find very interesting. But most of his piece is right on. Well worth reading, especially if you consider that you're free to think, do, and feel whatever you want.
To me, this would be a horrible way to exist. Isolated. Cut off from reality. An island unto myself. Fortunately, there's much more reason to deny free will, than to accept it.
Here's some excerpts from Harris' The Marionette's Lament.
Let’s begin by noticing a few things we actually agree about: We agree that human thought and behavior are determined by prior states of the universe and its laws—and that any contributions of indeterminism are completely irrelevant to the question of free will. We also agree that our thoughts and actions in the present influence how we think and act in the future.
We both acknowledge that people can change, acquire skills, and become better equipped to get what they want out of life. We know that there is a difference between a morally healthy person and a psychopath, as well as between one who is motivated and disciplined, and thus able to accomplish his aims, and one who suffers a terminal case of apathy or weakness of will.
We both understand that planning and reasoning guide human behavior in innumerable ways and that an ability to follow plans and to be responsive to reasons is part of what makes us human.
...We agree that given past states of the universe and its laws, we can only do what we in fact do, and not do otherwise. You don’t think this truth has many psychological or moral consequences. In fact, you describe the lawful propagation of certain types of events as a form of “freedom.”
But consider the emergence of this freedom in any specific human being: It is fully determined by genes and the environment (add as much randomness as you like). Imagine the first moment it comes online—in, say, the brain of a four-year-old child. Consider this first, “free” increment of executive control to emerge from the clockwork.
It will emerge precisely to the degree that it does, and when, according to causes that have nothing to do with this person’s freedom. And it will perpetuate its effects on future states of his nervous system in total conformity to natural laws.
In each instant, Austin will make his putt or miss it; and he will try his best or not. Yes, he is “free” to do whatever it is he does based on past states of the universe.
But the same could be said of a chimp or a computer—or, indeed, a line of dominoes. Perhaps such mechanical equivalences don’t bother you, but they might come as a shock to those who think that you have rescued their felt sense of autonomy from the gears of determinism.
...An illusion about mental freedom seems to be very widespread. My argument is that such freedom is incompatible with any form of causation (deterministic or otherwise)—which, as you know, is not a novel view.
But I also argue that it is incompatible with the actual character of our subjective experience. That is why I say that the illusion of free will is itself an illusion—which is another way of saying that if one really pays attention (and this is difficult), the illusion of free will disappears.
...In my book, I argue that an honest look at the causal underpinnings of human behavior, as well as at one’s own moment-to-moment experience, reveals free will to be an illusion. (I would say the same about the conventional sense of “self,” but that requires more discussion, and it is the topic of my next book.)
I also claim that this fact has consequences—good ones, for the most part—and that is another reason it is worth exploring.