(The following are simply lines of thought on my part. I make no claims of accuracy or claims that they are indeed true, even though to me they seem logical.)

Humans, obviously the most successful creature on this planet. Dominating every other species, even driving a great number of them to extinction, humans think themselves above and separate from animals.

Well, thinking something, doesn’t make it so. Pick up any newspaper, look or listen to any news report; it most surely is not evident from what we do that we are totally severed from our primitive past.

Humans still display many of the primitive behaviors that animals possess. Flight or flight, the drive to procreate, even the caring of young are shared behaviors of humans and many other animal species. Other? Yes, other.  Humans, whether they like to admit it, and despite denials to the contrary, are simply animals.

The fact that we are animals does not lessen humankind’s position, pecking order, status, or whatever. Human’s have climbed to their present position through great trial. Human beings are indeed a wonder to behold. We do not see that fact as we have always been ourselves. An impartial observer, had there been one, looking upon and measuring human progress would have been deeply impressed. After all, despite a bottleneck caused by who knows what calamity, we, humankind, bounced back from near extinction, a near extinction that occurred between 70,000 to 100,000 years ago. In spite of being reduced to nearly 2000 , we arose once again to dominate all other species. This is much more grand a concept than the assertion that some deity snapped humanity into existence in an instant. This grander concept has facts to back it. The deity, name any, never had anything to substantiate its existence, ever. 

The religious deny their animal origins and as a result fall prey to animal predilections in great numbers. If you are not aware of the beast within you then it can catch you unguarded. Working behind conscious thought there is a primitive mind with primitive drives. When it surfaces it causes problems in the world of civilized humans. Evolution built our advanced brains, but it didn’t start from scratch. It built it in addition to, adjacent, under, or over the primitive brain. If a perfect God had built it there would be no primitive drives, no primitive structures, as it would be perfect also.

Even so, it is our primitive beginnings we have to thank for our present humanity. Perhaps it is to blame for our present humanity as well.

Many animals share food. It is a behavior sometimes called reciprocity. When animals scavenge for food, some find it, others do not. Those that share it are more likely to have the same favor deeded them, by those they share with, when fortunes are reversed. I believe this type of event precipitated caring, at least as soon as the mind of the human animal grew capable of such concepts.

Shame also grew from primitive beginnings. Primitive ape-like creatures that lived in social groups often ran afoul of one another and many a bully needed to be properly punished for disrupting the harmony of the group. Such punishment sometimes led to banishment from the group and then certain death. Those that stayed and endured the punishment survived. Displaying a timid, possibly, shamed appearance, might diminish the level of punishment.

This shame, I postulate, might be the foundation of the concept of sin. The feeling of shame and guilt, became sin.

As the human animal became more sophisticated the concept of sin, as a result of shame and guilt at having broken some rule or etiquette of behavior, needed atonement. Admitting sin became fashionable. Being unworthy became a trend. Admitting sin became a way of alleviating guilt and receiving quicker forgiveness from the community at large.

No doubt having already invented Gods for the purpose of explaining the unexplainable, these Gods were a handy agency by which to gain quick reacceptance by the community by having their transgressions forgiven. If your sins have been forgiven by Gods then who are humans to deny it?

Awareness, both that we are products of a development process that spanned millions of years and that we are still relative newcomers with much further to go, should caution humankind. We have to realize that we must think before we act. The primitive mind is still within us and can respond quicker than the more developed mind we now also possess. It takes longer to think out a weighed response than it does to respond with a knee-jerk. I hope we have matured enough to realize this, though, from the evidence, it doesn’t seem that we have.

I recommend these books:

“Why Evolution Is True”, by Jerry Coyne

“Your Inner Fish”, by Neil Shubin

“The Greatest Show On Earth”, by Richard Dawkins