"what is actually good flows from our nature"... [is] begging the question

I wasn't aware we were arguing metaethics at that level here, so a charge of begging the question seems entirely out of line.

That what is good comes from the sort of thing that one is, is not all that controversial. It's actually one thing I didn't have to explain or defend at all in my thesis on ethics, but as always your panel may vary. Let's go through a few candidate explanations of the good:

1. The good is objective, and based on universal principles; it's pure chance that we care about what's good
2. The good is objective, and based on universal principles; we care about what's good because our observations about the good track reality
3. The good is objective and relative; what is good for a human is based on what it is to be human
4. The good is subjective; what is good as far as I'm concerned is not based on any facts about the universe other than some human's say-so

I'm leaving out explanations of the good such as Divine Command Theory and Ethical Nihilism since I assume you wouldn't buy into them anyway.

In each of these cases, what is good comes from what it is to be human. Our nature is the grounding of value, and to ignore a major part of our nature is sure to lead one astray when seeking out the good.

Did you have another idea in mind for what constitutes goodness?

That's as much begging the question as saying there must be a God because he's good, and all the good we have in the world must therefore flow from His love.

That's not begging the question either, though I suppose it might be if it was stated more clearly. Does anyone actually argue that, anyway?

It's good because good flows from our nature, and our nature is good because discarding it is bad?

No. I did not argue that our nature is good. That would indeed seem circular.

And of course, you're still begging the question of why "part of our nature" equals "certainly bad" to "discard".

Sorry, were you using 'begging the question' in the colloquial sense this whole time? I'd assumed not, since you referred to Aristotle. If not, please point out where I'd initially set out to prove that "part of our nature" equals "certainly bad" to "discard". I'd initially used (something like) that as a premise and not my conclusion!

If you see what I'm doing as "just babbling" then I don't see how you even have anything to argue against. You're being disingenuous, at best. That I'm taking fairly standard philosophical views and arguing using logic should not equate to "just babbling".