All I conclude is that:
- If God chooses to predestine salvation, man is saved.
- We observe this particular man is not saved.
- I conclude that God has not chosen to predestine salvation for this man.
Completely in agreement so far
If this man cannot save himself without God, then God’s choice to not predestine salvation for him, means that he will not be saved.
We differ here for several reasons.
Firstly, your phrasing seems biased when you describe it as God choosing not to predestine
salvation specifically. Under single predestination, it's actually God choosing not to predestine
either salvation or condemnation for this non-elect man. Your conclusion logically would just as equally be - "God's choice to not predestine condemnation for him, means that he will not be saved". This sounds ridiculous, doesn't it? And that's because you still read in monergism into the non-elect too whereas single predestination confines it to the elect alone. What could probably help you understand better is to apply calvinist doctrines to the elect and the arminian freewill doctrines to the non-elect.
I've listed out all premises, observations and conclusions of Single Predestination here for our reference -
1. If God predestines a man unto salvation, that man is assuredly saved.
2. If God predestines a man unto condemnation, that man is assuredly not saved.
3. If God does not predestine either, then God has decreed man to self-determine his destiny through faith.
4. If man self-determines to endure in faith to the end, then man is saved.
5. If man self-determines to not endure in faith to the end, then man is not saved.
6. We observe from Scripture that God predestines all the elect unto salvation.
7. Hence from #1, we conclude that all the elect are assuredly saved.
8. We observe from Scripture that none of the non-elect self-determine to endure in faith to the end.
9. Hence from #5, we conclude that all the non-elect are not saved.
If man cannot save himself and God will not save him, then how it not an inescapable conclusion that he will not be saved?
We'll have to discuss the nuance in the word "cannot" later and I would either say "God will not assuredly save him" or "God has not predestined him for salvation" - but these qualifiers apart, you'd see we arrive at the same conclusion in #9 - that he will indeed not be saved.
What third choice is there for salvation?
That’s like arguing ... ”God didn’t catch him and the man decided not to fly to safety” ... when the man is incapable of flying.
God didn't catch him = didn't predestine unto salvation (or condemnation) applies #3.
Man decided not to fly to safety = man self-determined not to endure in faith applies #5.
#3 AND #5 => #9 (he is not saved)
I don't see what the problem is here - why do you think I'm not concluding that such a non-elect person is unsaved?
What we're actually debating is not whether the non-elect is unsaved but what factors led to him being unsaved. Double Predestination applies #2 as what led to his not being saved. Single Predestination applies #3 and #5 sequentially for the same. We could continue debating the Scriptural merit of #3 (I'm assuming you're fine with the other points?) - but what do you find logically inconsistent in this single predestination system?