Essayist: The existence of a moral order in the universe—i.e., an order in which bad is always eventually punished and good rewarded—depends upon human souls being immortal.
Conclusion (it follows that)
If human souls are immortal, the bad will be punished (regardless of how the moral order is represented).
Evidence
The existence of a moral order depends upon human souls being immortal.
Evaluate
This argument is really hard to understand. We omitted the 2nd sentence from the reasoning core, because it's just providing inessential examples of how different moral orders handle the idea of the good being punished and the bad rewarded (this moral order thinks that cosmic justice is achieved via reincarnation/karma, while that moral order thinks that cosmic justice is achieved via a supreme being in an afterlife).
Since those are just two of possibly many examples, neither is crucial to the reasoning.
What we're left with feels a bit like a circular argument. Both the first sentence and the last (i.e. the premise and the conclusion) are talking about moral order / immortal souls / bad punished.
So is the premise just restating the conclusion (as we see in Circular arguments).
On the other hand, both the first / last sentence have conditional logic indicator words: "depends" and "if". Whenever we're doing Flaw and see conditional logic, we immediately worry about Necessary vs. Sufficient flaws (i.e. illegal reversals or negations).
So let's diagram these to see whether they're replicas of each other, in which case we should be thinking Circular, or whether they're an illegal reversal/negation of each other, in which case we should be thinking Nec vs. Suff.
The first sentence is saying "X depends on Y", which is the same as "X requires Y", which is diagrammed X→Y.
Moral Order immortal (where good rewarded → human souls and bad punished)
The last sentence uses "if", which is a sufficient trigger.
immortal human souls → bad punished
Goal
Okay, it's not a restatement, so it's not Circular. It's also not exactly an illegal reversal, but it's pretty close to that.
The first conditional had "bad punished" on the left and "immortal souls" on the right, and the second conditional has those two appearing on opposite sides.
So let's look for something like Necessary vs. Sufficient flaw, something addressing this weird switch.