Victor Reppert, author of C.S. Lewis' Dangerous Idea and keeper of a blog called The paper is relatively short and does a good job of covering the main issues.
It opens with the horrifying account of a murder that took place in England in 1993:
On February 12th 1993, British toddler Jamie Bulger was enticed away from his mother at a local shopping center and led away by his abductors on a short journey that would end in his tragic and horrific death on the railroad tracks three hours later. Evidence at the trial of the two perpetrators indicated that there were points along the way that they could have changed their course of action. Instead, they brutalized, sexually molested, and battered the child to death with bricks and an iron bar before laying his body across the tracks in hopes of hiding evidence of their involvement in his death. The two murderers, Jon Venables and Robert Thompson, were ten years old (Scott).
From a determinist point of view, Jon Venables's and Robert Thompson's fate was set even before their birth. Born to ill-educated, working class parents, the details of the boys' lives constitute a veritable catalogue of social ills. Venables's parents were unstable and depressed and the father eventually abandoned the family. The boy's older and younger siblings were both developmentally challenged and he suffered the brunt of his suicidal mother's physical and verbal abuse. When arrested for the murder of Jamie Bulger, Venables was described as "nearly illiterate" (Slaughter). Thompson's environment was even worse. The second to the youngest of seven violent and aggressive boys, he was, early on, exposed to the criminal habits of his brothers, one of whom was an arsonist and another who was a master thief. Both parents were alcoholics and the father beat the mother regularly. Given the effects on the boys of the atrocious environments and their family histories of alcoholism and abuse, could Venables and Thompson be said to be morally responsible for the actions which led to the tragic death of Jamie Bulger?
The difficulties in trying to navigate between free will and determinism seem intractable. The determinist challenges the libertarian (one who believes in free will) to explicate the nature of a genuinely free choice. Is a free choice one that is completely uncaused? That can't be because our choices, especially our moral choices, arise out of, and are in some sense caused by, our values and beliefs. If our choices are uncaused then they would seem to be spontaneous, unrelated to anything, and, if so, how can we be responsible for them? So, the challenge for the libertarian is to explain how a choice can be influenced by our character, and how our character can be influenced by our environment and genetics, without being determined by these influences.
On the other hand, determinism, if true, has several very unpleasant implications. If it's true then reward and punishment are never deserved since if our choices and behavior are determined by environment and genetics and not freely chosen, an individual is not responsible for anything he does. He's just a passive piece of flotsam swept along by forces outside of his control. Moreover, if determinism is true there can be no moral obligation for one cannot be obligated to do what one cannot do. Finally, determinism is dehumanizing because it tells us that that which makes us unique as humans, the ability to choose our behavior, is just an illusion. On determinism we are essentially robots which means that the idea that humans have dignity and worth is also an illusion.
There's one more problem with determinism. The determinist holds that we always act upon our strongest motives, but the only way we can assess which motives are strongest is to see what it is that we choose. For example, if I choose to have cereal for breakfast the determinist would tell me that my strongest motive was to eat cereal, but if I chose instead to have pancakes he would say that my strongest motive must have been to eat pancakes. In other words, we can only discern our strongest motive by looking at the choice we made. If this is true, however, it means that determinism reduces to a tautology. Since our strongest motive equals whichever motive we act upon the above italicized claim says nothing more than that we always act upon the motive that we act upon. This is true but not very edifying.
So what's the upshot? Philosophical reasoning seems unable to settle the question. There's no compelling reason, if one is a libertarian, to give up one's belief that one is free. One must decide on other than philosophical grounds where one will stand on the matter. If, for example, one believes that we are all accountable for our actions, that people are not just robots, that there are genuine moral obligations, and that at many moments in our lives there really is more than one possible future, then there's no compelling reason the determinist can give to persuade us otherwise. Nor, for that matter, is there reason, if one is a determinist, if one believes that at every moment in our life there's only one possible future, to give up that belief as long as one is willing to accept the existential consequences.
Anyway, read the article at the link. It's quite good.
RLC
