Replying super late so I doubt anyone will see this. But....

The idea is that the human conscience cant be explained. Obviously that doesnt prove any god exists (let alone a specific god), but its a gap in knowledge. And, a moral compass to follow (or choose not to follow) is a pretty reasonable thing for a creator to create.

The human conscience isnt taught (although a healthy upbringing usually reinforces it), and it isnt logically deduced (although logic often reinforces it). Its unlikely that its instinctive because it can be somewhat counterproductive to other instincts. Being a nice person is actually not the best way to pass on your genes (especially pre-civilization), and may not even be the best way to individually survive. Why would we have counterproductive instincts?

Does anybody have a reasonable explanation for why we all have a conscience, or a decent argument that we dont all have a conscience?