I recently had a discussion at lunch with some friends and we went through the five points of Calvinism. This was essentially our conclusion:
1. Total Depravity: essentially the idea of original sin. Because of the Fall, man is sinful by nature and is helpless without God. There isn't much I can really say about this doctrine (I will expand more on this later). Some may try to blame Adam for essentially damning us all because of his action in the Garden. But, would you have acted any different? No, our nature is sinful and we must, only through the Holy Spirit, choose to follow God in faith. Without the guidance of God, man is eternally helpless.
2. Unconditional Election: God, before eternity, chose some to be saved and some not; not based on any merit, choice or sin. Man, due to his depraved state, cannot choose his salvation. God holds all the power to give mercy to those he elects. The Calvinist conception of this predestination is used to show the power and grace of God's love:
11For the grace of God that brings salvation has appeared to all men. 12It teaches us to say "No" to ungodliness and worldly passions, and to live self-controlled, upright and godly lives in this present age, 13while we wait for the blessed hope—the glorious appearing of our great God and Savior, Jesus Christ, 14who gave himself for us to redeem us from all wickedness and to purify for himself a people that are his very own, eager to do what is good."
This fits right with what I have been saying. With the help of the Holy Spirit we can say 'no' to our sin and live lives of righteousness through Christ.
I leave off the last two points: "Irresistible Grace" and "The Perseverance of the Saints" because I feel they can be reconciled and are more or less true. Once you are saved, you are always saved and cannot be un-saved. If you believe yourself to be saved but do not live a life of righteousness then perhaps you were not saved to begin with.
So, now where are we? What if I am a reprobate? What am I if not saved truly? There is no way I can know. I must live the Christian life and act accordingly. I have faith in God and I believe in the power and sufficiency of His will.
There are some more specific details that I omitted due to a)the length already, b)laziness, c)I aimed to just get the general points. We can discuss this together sometime if you would like. I always love a good philosophical discussion among friends.