Calvin made someone Catholic? That's more logical than you'd think - as Calvin represents perhaps the most illogical of the "way out there" protestant "theologies."
Tell me, Dr Eckleberg, why would anyone need to go to church, atone for their sins or accept Christ if this "predestination" garbage were actually valid?
And by the indwelling Holy Spirit, we do just that, knowing full well whom we have believed.
Read Ephesians 1 and 2; Romans 8 and 9; Colossians and Hebrews. It's all there, if you have been given eyes to see and ears to hear and a new heart with which to understand and believe.