A few more comments on this:
Shortly after this I reassessed my belief in Calvinism and let it corrode under the sweet promises of Scripture: that eternal life is given to all those who believe in the Son of God—Jesus Christ.
i) Come again? Calvinism affirms that eternal life is given to all those who believe in Christ.
ii) Perhaps he means that according to Calvinism, some people who initially believe in Christ subsequently lose their faith. But, if so, the same holds true for freewill theism (Molinism, Arminianism, open theism).
After intense study of all these matters I came to doubt many of the core beliefs of the faith. I did not express my doubts to many people, though I often confessed to others that I was struggling with a terrifying fear of death and did not know I was saved.
On the face of it, his logic is backwards. If, say, you came to doubt many of the core beliefs of the faith, it would them make sense to doubt your salvation. For at that point you doubt the very framework of sin, salvation, and a Savior. If, say, you came to doubt the veracity of the Gospels, then it would make sense to doubt your own salvation inasmuch as you now doubted the larger story in which that's embedded. If you doubt Christian soteriology, you will naturally doubt your own salvation. What is there to be saved from?
But why would doubting his salvation cause him to doubt the Christian faith? How does the loss of assurance in his salvation lead to doubting the historicity of the Gospels, the Resurrection, &c.?
It seemed to me that the only way I could know I was saved was by knowing the status of my eternal election. Was I chosen by God for salvation or was I eternally damned before I had done anything good or bad? To be sure, the Calvinist theologian in me had responses to this question, yet none of them sufficed…my Calvinistic theology presented my needs for assurance with an epistemological problem: in order to have assurance I needed to know the status of my election, something that by definition is secret and cannot be known.
This objection was articulated in an article by William Lane Craig entitled “Lest Anyone Should Fall”: A Middle Knowledge Perspective on Perseverance and Apostolic Warnings where he essentially argues that the “means of salvation view” is actually more coherent in a “middle knowledge” perspective. Middle knowledge is the view of God’s knowledge that contains what his creatures would freely do in any given circumstances (or “possible world”) before he creates the world. This contrasts with the Calvinist perspective in that it allows for libertarian free will, which is a view of freedom that is incompatible with causal determinism.
That's like grounding the assurance of salvation in Monadology. There's absolutely no evidence that Molinism is true. There's no empirical evidence, revelatory evidence, or philosophical evidence.
It's like saying: Planet earth is dying. We need to colonize another planet to survive. An astronomer has postulated a Class M planet in a particular solar system in the Milky Way. We only have the technological wherewithal to make one trip. So let's go there.
Mind you, there's no empirical evidence that a Class M planet exists in that location. But given the size of the Milky Way, it's possible that the astronomer's postulate is true. We might get very lucky.