Was sin necessary for knowledge?

[vulcanlogician]

That would entirely depend on your definition of sin and morality. If you define sin as: what is morally wrong to my person, then a moral knowledge would be necessary. I do not define sin that way so I disagree and we have not discussed morality

Do you define morality as having conscience or remorse for perceived wrongdoing?
If you do, by CL and your definition: Socipaths couldn't sin because they have no moral knowledge

I'm open to persuasion though.

To keep things simple, I define immoral behavior as anything that is interpersonally destructive. There is a bit more nuance to my moral views, but that is good enough for the purposes of this conversation.

I would bring in the example of wild animals. I don't hold animals morally responsible for their actions. They operate on instinct; their capacity for reasoning is rudimentary compared to ours. They have no concept of right or wrong.

As far as "sin" goes, that word can mean a hodge-podge of different things. It is hopelessly entwined with the concept of morality, but also encapsulates many Judeo-Christian cultural mores-- many of which have little to do with morality. Even in the Bible, "sin" can refer to a transgression against the Law or (as Paul would have it) pretty much everything a human being does before he/she embraces Christ as their savior.

I think Adam and Eve says something poignant about our being "cursed" to be morally responsible agents. As far as "sin" goes, aside from the moral element, it's pretty much a meaningless concept to me.