Unfortunately, this is one of those arguments that seems to polarize. You're pretty much either a Calvinist or Arian with neither side allowing the middle ground. Those horrible "Arians" (which IMHO is a misnomer anyway) deny that God is all powerful because they assert some degree of free will. Talk to any Calvinist and they'll swear to you up and down that free will must mean total choice and practical self salvation... With the Calvinist bunch, you must believe that God laid down everything (which he did) but that he also planned everything out as it has unfolded apparently for his pleasure. One thing that's often not admitted is that predestination would make Satan himself molded by God to be evil. There are some ambiguous attempts to get around this, but they border dangerously on the free will side of things!
My point with the sarcasm is that this argument gets tired and it gets well overheated.
I'm reminded of Christ on earth, and the many verses where it says he perceived something:
[bible=Mark 2:8]
And immediately when Jesus perceived in his spirit that they so reasoned within themselves, he said unto them, Why reason ye these things in your hearts?[/bible]
Scriptures like this, scattered throughout the entire Bible, really give no doubt as to the ability of God to be a heart-knower (kardiognostes as he is called in the New Testament). I don't think any true Christian, regardless of stance in this debate, will deny that aspect of God. It's pretty much plainly stated right there in black and white (or perhaps red and white for you red letter edition readers). We can go back to Pharaoh and see that God can know the intentions of a person and even harden his heart. Lots of folks like to entirely misconstrue this verse and say that God made Pharaoh's heart hard while the verse simply says hardened (Exodus 7:13, etc.). A heart can already be hard yet still hardened further when the intentions are dark. So we can further take existing Biblical statements and build upon the foundation. God knows hearts and can discern the intent of someone to do something based on their heart.
A hypothetical Calvinist would stop here and say surely it means that God hardened Pharaoh's heart to further the plot of what would eventually lead to the elect. Here is undeniable proof of predestination.
The problem with this assertion is that it doesn't regard the entire Bible. To me it has always seemed very easy to build a case for Calvinism, but I've never been able to assent fully to the doctrine because of some key issues. I'll start from the beginning with Adam.
[bible=Genesis 2:7]
then the Lord God formed the man of dust from the ground and breathed into his nostrils the breath of life, and the man became a living creature.
[/bible]
The ESV and other modern versions do a better job here of rendering nephesh than the KJV. Some would like to take this would and render it (like the KJV) soul. The problem with that in my book is that it's used in Genesis 1:20 to talk about animals. In fact, the word right before it is "living" (Hebrew chay). A living soul would be repetition if you interpret it in the manner that the nephesh is the soul. However, if you were to distinguish this as an earthly soul (IE: creature, being, etc.) then the sentence makes sense. Father formed the body and breathed the spirit, but it never makes the claim that here God created the soul.
Jumping to another one:
[bible=Jeremiah 1:5]
"Before I formed you in the womb I knew you, and before you were born I consecrated you; I appointed you a prophet to the nations."
[/bible]
Interesting, it's the exact same case here! If you approach this with the notion that we are a soul at conception, then perhaps you could argue the Calvinist view here.
Verses like Ephesians 1:4 and Romans 8:29-30 leave me with the obvious question. If God knows us before the foundation of this world, then is there no other conclusion but all things (both good and evil) are knowingly created by God? I don't think folks fully grasp the meaning of that statement because it's saying God knowingly created Satan as a foil to his children. Typically the "God works in mysterious ways" card is played right here and the question simply floats. I think those who are content with not seeking simply stop here and stick with the Calvinist mantra while those who are not so sure about the ambiguity tend to fall in the free will camp.
The key for understanding comes in Ephesians 1:4 (as elsewhere) when the word katabolē is used. This word literally means to throw down and it is only used in reference to the foundation of the world. It is not used anywhere else despite other words being used elsewhere for foundation like Luke 6:49, Luke 14:29 , Romans 15:20, etc. This alone should stir curiosity.
Returning to Ephesians 1:4, the next word is the Greek kosmos. As I explained in another thread, kosmos refers to the current ordered age to put a phrase on it. It's like saying "the universe as it stands now." This verse is effectively saying we (like Christ) were predestined from the literal throwing down of the foundation of this age/era.
This is, beloved, for those with eyes and ears to see and hear respectively, but do you not see that the soul is never created. Consider deeply Hebrews 4:12. The Word can and does certainly divide to that point. These elect are predestined in that they come from before, when their souls (not their bodies, this is not reincarnation Hebrews 9:27) existed prior to this era/eon/age. Father God knows them from somewhere, he has reason to trust whom he can trust. Just like Paul and others, God interacts with these people because he knows them and knows he can use and trust them to get the work done.
This is the truth behind predestination. It will step on a lot of toes, and I'm used to about anything that can be said, but I don't say these things with the faith I do because I take them lightly. Our God, YHVH, has written us a letter with an explanation of so many things about him. He's given us the Ruach Adonai to validate these things. They do become clear to some while maybe ending up on the shelves for others. That doesn't make one better than the other, because they're all God's children. What's so wild is that some of you will disagree with this and not believe it, yet most (if not all) have come to conclusions about this existence that have already placed you on this track. Did you end up at this forum talking to these people by chance? I really don't believe that. I'm not trying to force or assert, but I will let the truth flow as much as possible on this community and you are free to believe what you believe between you and Father. Talk to him and search the Scriptures, you'll find a lot of amazing things to be true.
I say all of this not to insult anyone. When you get right down to it, both schools of thought are correct in their own ways. Let's use the tools God gave us to split in two and be precise.
God Bless.