As we've compared the compatibility of the theistic and atheistic worldviews with our existential experience I've argued that there's a significant number of facts about the world and about human life that make more sense given the truth of theism than given the truth of atheism.
To those facts we've already considered in our previous posts we can add our sense that we are free to make genuine choices and that the future is open. In the absence of God our intuition that we are free to choose and are responsible for those choices is problematic. In a Godless world we are just a collection of physical particles, and ultimately physical particles have no freedom, they simply move according to unyielding physical laws. In a Godless world our choices are nothing more than the product of chemical reactions occuring in the brain, and the reactions themselves obey the mechanistic laws of chemistry. There's no freedom in chemistry.
Thus for the atheistic materialist there can be no free will. There is only the inexorable laws of nature. At any given moment there is actually only one possible future, if there is no God, and our belief that we can freely create the future is pure sophistry and illusion. The future has been fixed since the Big Bang.
Consider the words of atheist Will Provine, an evolutionary biologist as he summarizes the views to which his Darwinism has led him: "There are no gods, no purposes, and no goal-directed forces of any kind. There is no life after death ... There is no foundation for ethics, no ultimate meaning in life, and no free will."
If there's no free will in the atheist's world then an atheist who faults me for writing this post would be acting inconsistently with his own assumptions. If there is no God I am driven to write by causes beyond my control and for which I am not responsible. Indeed, if there is no God, it's hard to see how anyone could be ultimately responsible for anything they do.
An atheist should be a determinist, but this puts him in a bind. If determinism is true then those who believe it do so for reasons unrelated to its truth, and those who disbelieve it should not be criticized for their disbelief since their skepticism is mostly a function of their genes and environment, over which they have no control. Should a determinist argue that he believes determinism because it's true he's pretty much denying the belief he claims to hold. If someone believes in determinism it's because he was determined by his life's experiences and/or his genetic make-up to believe in it. The truth of determinism is irrelevant or, at best, incidental to whether we believe it or not.
RLC