That's an old argument, constantly revived, more recently by people arguing that because totalitarian theocratic regimes existed throughout history and still exist today, it's somehow an indication of the divine at work. Despite the incredible evidence that they're not serving the same deities and that even those who do, cannot agree with eachother on doctrine, because of the lack of actual divine manifestation.
A better explanation is that human brains are unreliable and that people have manipulated humanity with human weaknesses. An innate weakness of the brain is assessing reality. An instinctual fear is death, so religions and philosophy entertain endless arguments in attempt to claim that death of the individual is not the end, or that the limitations of the individual exceed reality. The same with magic traditions that go back before massively organized religion.
We have evolved but not efficiently for reality discovery. A long time was needed for the scientific method to really develop and for humanity to finally discover the world. Despite efforts to fight illiteracy. Human languages, including mathematics, can describe things in terms that that the human mind can deal with, but those ideas may still remain outside of reality and may even consist of reality denial arguments, part of a tradition to dismiss actually reliably discovered knowledge.
An actual effort is required to go further. Actual divine manifestation would be required to really support this argument and there only exist stories of such as well as limited personal experiences, better explained by how the brain works.
It seems that the discovery of the brain was an embarassment to religion, to a point where modern pseudoscientific arguments are endlessly entertained, like claiming that it's an antenna for the soul, or works with quantum magic...
As for conscience and "sin", ethics, empathy and law codes can remain part of human preoccupations as they always were, without appeal to a supposed divine origin. Afterall, they're a very human phenomenon...
When you erroneously believed that objects no longer existed because they were outside of your vision field, you grew up out of it. Do you remember confusing people on TV with those in the room? You grew out of it. Do you remember imagining beings in dark places, like under your bed and in the wardrobe? You likely grew out of it. But you still entertain deities of the gaps. Grow up! :)
Edit/Adding:
I forgot to mention toys, dolls and plush animals. Many will remember when a particular plush animal was perceived as a real animal or perhaps even as a person. Kids eventually also usually grow up out of it. It seems very relevant, because in prayer the same mind conditioning is involved to sustain an imaginary person.
