Coke or Pepsi? It’s a simple question really. If sitting before you were a can of Coke and a can of Pepsi, which would you open and drink?
I suppose an even better question would be, are you free to choose either Coke or Pepsi? In other words, do you have free will, or is your choice predetermined?
I confess to you that I do not have free will to choose Coke or Pepsi. When faced with a “choice” between Coke and Pepsi, I will always choose Coke. I cannot do otherwise — it tastes infinitely better! And I will always choose what I desire most. And that means I will always choose Coke.
Ah, but you may say, I can choose Pepsi in order to prove that I will not always choose Coke. Yet, this does nothing but prove my point, as I am still, at that moment, choosing that which I desire the most. But now, my desire to attempt to deny a basic philosophical tenet is stronger than my desire to drink something that tastes better.
It doesn’t matter what your reasoning is. It could be craving a certain taste, looking to cut calories wherever possible, or perhaps it is the only drink available (in which case you are still making the decision to drink Pepsi instead of going thristy), I guarantee that you will always choose that which you desire the most — and in that sense, you do not have free will, and your choice has been determined by outside circumstances.
There are exceptionally few philosophical or theological conversations that are more sensative and volatile than the notion of free will. Yet, when we look at it in simple terms of Coke and Pepsi, it becomes a rather simple and straightforward matter.
Can it bridge the analogical gap to the Gospel and our response to it, though? I believe it does!
Think of it. We always choose that which we desire most. As you go throughout the day today, think about what you decide to eat, how you choose to spend your time, and with whom you converse. I guarantee that you always choose that which is higher up on your scale of values. You may not want to watch six hours of kids’ television programs, but you prefer it over your child bouncing off the walls, distracting you at every moment. You may not want to eat macaroni and cheese for dinner, but you do not want even more to overdraw your checking account for six ounces of filet mignon.
Bridge the gap to the Gospel. What does the Bible say is our natural born relationship with, and response to, God?
There is none righteous, not even one; there is none who understands, there is none who seeks for God; all have turned aside, together they have become useless; there is none who does good, there is not even one. Romans 3:10-12
For while we were still helpless, at the right time Christ died for the ungodly… God demonstrates His own love towards us, in that while we were yet sinners, Christ died for us… If while we were enemies we were reconciled to God through the death of His Son… Romans 5:6, 8, 10
You were dead in your trespasses and sins… Ephesians 2:1
The Word of God makes it clear that our natural inclination towards God is not a favorable one. No one seeks after God. Period. Paul does not put an asterisk after “none” so as to introduce a caveat. We were enemies with God until He initiated the act of reconciliation (also cf. 2 Corinthians 5:18-19). We were dead in our sinful state.
I could list more Scripture, but even one passage is enough to establish a doctrine as divine. Just as our wills are not free to choose Pepsi or Coke without outside circumstances, so we are not free to choose Christ without some external stimulus, which is the Spirit Himself.
Perhaps at a later time I could further draw out the implications for every day life, in case the Coke/Pepsi dichotomy proves insufficient, but suffice it to say that I believe each and every decision we made is, in some way, predetermined. Whether that predetermination begins and ends solely with our desires, or whether God ordains it all (or perhaps some inquantifiable percentage in between), would certainly be the topic of a future post.
But for now, my goal was first to bring this theological and philosophical hot topic into the realm of every day life.
Awaiting That Day 
I agree with the final analysis as you made the bridge to the gospel. Without a doubt, we are slaves to sin unless the Holy Spirit convicts our hearts and the Son makes us free indeed. I did have issue, perhaps only with the wording, of this one phrase that you wrote:
“I guarantee that you will always choose that which you desire the most — and in that sense, you do not have free will, and your choice has been determined by outside circumstances.”
Is our choice DETERMINED by outside circumstances or is our choice DEMONSTRATED by outside circumstances?