Why Did You Believe and Others Did Not?

In an encounter with some Calvinists, one of them kept asking (more like demanding) why did you believe but others didn’t? Being that they are Calvinists, what they want to say is that the reason one person believes and others don’t is because we’re just following our nature. They want to say that God gave some people a nature to believe and others a nature to reject him. They like asking that question because it gives them a nice simple answer, while those of us who believe that the nature God gave us is to have the freedom to make choices have a hard time answering it. I can point to plenty of things that led up to me accepting Christ, but I can no more say why I made that choice than I can say why I sometimes choose vanilla ice cream and sometimes chocolate ice cream. So, I told the person that I could no more answer that than they could answer why God chose them. Interestingly, the person responded by saying, “I know why God chose me,” and then he quoted, Ephesians 1:5, “Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will.” This is interesting, because, though I have problems with the way they are using this verse, the fact that they did use this verse in this way gives me a way to answer their question. Obviously, if God choosing us by “his good pleasure” is a sufficient answer for why God exercised his freewill in the way they believe he did, then for me to say that “it was my personal preference” is a sufficient answer for me to explain why I made the decision that I did through my freewill. As you might expect, the Calvinist wasn’t satisfied with my answer. The problem that Calvinists have is that they presuppose determinism. They don’t really want an answer to “Why did you believe but others didn’t?” They want an answer to “What is the deterministic reason that you believed but others didn’t?” Of course, that is just question begging. If God has freewill and God has the power to make creatures that have freewill, then we can’t just assume that our every action is predetermined. To make it worse, Calvinists borrow from the concept of freewill to keep their doctrine from making God the author of sin. They will say that we’re just following the sin nature that God made us with, but God isn’t the cause of our sin. If you mention that their doctrine makes God the author of sin, they squirm like worms when you remove the rock they are hiding under. They never provide a good explanation for it, rather they say things like, “You don’t understand Calvinism” or “You can’t understand things that are spiritually discerned, because you are carnal.” When the simple fact is that their doctrine is just wrong.