Part and parcel of any thinking about salvation is the perennial tough nut of free will. In a similar fashion to the problem of consciousness (which I think is related) you can have the Hard Problem and the Easy Problem of free will.
Start with the Easy Problem (it is best we call them "easy problems"): this is the challenge to explain our ability to discriminate, to choose (in the naive definition of the term). These are "easy" because we can quantify such issues and measure them. In short, they are easy because they are natural, or can be explained through natural means. Things like, how long it takes to make a decision, what is the affect of adding variables to decision making, etc. These experiments are carried out by psychology depts constantly. The results from such analysis are used by marketers to develop brands and ad campaigns. In short: we understand this level of freedom quite well.
The Hard Problem, conversely, takes us into the realm of the spirit, which makes it impossible ot be discussed in the terms above. In short, the issue of free will is a theological question (perhaps also a philosophical question), not a scientific one.
The more "common sense" view of free will assumes because I can pick one brand of product over another or watch one TV show over another that I am free. But what we fail to understand is that we "choose" within a world of formal relationships. These relationships are nurtured by advertisers, marketers, brand designers, yes, but they are also by the zeitgeist, social mores, culture, time. In other words, these choices are substantially constrained. Of course, the more constrained they are the better it is for marketers because prediction is easier. And prediction equals profit. This is important.
It is not all Machiavelian though. If, back in the savannah, I could predict more successfully which bush had the bird and which bush had a sabre-tooth tiger, then I was more likely to live long enough to have offspring and so on.
The hard problem is hard because we need to look past all these constraints, bracket them aside and say "Am I truly free to choose?" In a cosmic scale, where the accidents of birth (time/place/genetics) are irrelevant, is there freedom?
If I cannot choose freely, then in what sense can I be held accountable for my actions? If I cannot do but what the grid within which I am moved (not self-propelled, but impelled by irresistable forces), then in what possible sense can I be said to sin? Or to choose Christ?
It seems we come down to a choice between free-will and determinism.
To add some difficulty to this, since I am not one to be find of binary arguments, one needs to take into account many nuanced positions – free-determinism is a spectrum, and different systems fall within different parts of the scale – see here: http://en.wikipedia.org/wiki/Free_will.
One constant is that we prefer freedom. It is the more attractive, and sometimes seems the more natural answer. No one wants determinism! But the reality is that almost all of the questions regarding free will are of the "easy" type, and almost always we can show that freedom is at best constrained, sometimes severely curtailed.
Many times these constraints are voluntary, or at least inherited as a system of beliefs which make acceptance of them optimal for not only surviving but thriving within said environment.
We prefer freedom because God is free, and we are made in His image. Our soul hankers for freedom in all matters.
Why does this all matter? Because if there is free-will then I am accountable to my choices, if there isn’t then I am cannot. If there is free-will then I better find it, nurture it, protect it, most of all protect it. Being vigilant to defend my freedom, even if it is the freedom to proclaim Christ, is the gift of the martyr.