If brain capacities are not the result of our evolution, what is your alternative explanation?
— Questioner

The question is improperly framed as it presumes that morality can be explained by neurology.

WE learn more about the development of moral codes by studying the development of moral codes than by studying the human brain. .
— Ecurb — Wayfarer

The proposition put forward in the OP is that there is "no secular basis for morality."

This implies that all morality grows out of a religious tradition.

No. The morality came first. We evolved the neurological capacities for it. Our evolution as a social species refined it. Toss in the capacity to invent supernatural beings, and the evolution of a theory of mind, and we see the rise of things like religious rituals, myths, taboos, and burial practices.

As the practices spread, politics enters the fray, and voila, organized religion.

The proposition put forward in the OP is that there is "no secular basis for morality."

This implies that all morality grows out of a religious tradition.

No. The morality came first. We evolved the neurological capacities for it. Our evolution as a social species refined it — Questioner

Straight out of the Dawkins Dennett playbook. Evolution displaces religion becuase it's scientific. You clearly haven't understood anything I've said about it, so no use repeating myself.

You've moved to a teleological account. Teleology explains what counts as flourishing. It does not explain why flourishing is obligatory. — Banno

Yes, that seems fair. I guess the more observant among us would probably say: surely no one would willingly go against God if they had certain knowledge or faith?

In addition, one cannot act otherwise than in accord with the structure of reality. Both kicking the pup and feeding it are possible; Either is "in accordance with the structure of reality itself". "Acting in accordance with the structure of reality itself" tells us nothing about which to choose. — Banno

That made me laugh. I'll need to think about it.

...surely no one would willingly go against God if they had certain knowledge or faith? — Tom Storm

Ask Lucifer...

That made me laugh. I'll need to think about it. — Tom Storm

Worth considering in terms of "flourishing", to see how it doesn't help. We could feed the pup or eat it. Both incur flourishing. Which is obligatory?

You clearly haven't understood anything I've said — Wayfarer

I feel the same way.