A basic biological creature – an emu, perhaps – only deals in the physical. Life is all hatching and growing and foraging and mating and running and dying. Often it’s not quite that good.
By the naturalist’s account, this ought to be everything for humanity, and we may as well enjoy it while it lasts.
It would be everything, except for that pesky “brain virus” that clings to religion, that continues to believe old fairy tales against all experience and evidence…or so they would have you believe.
I don’t notice the godless being all that critical about paganism. They will tell you this is because the pagans do not trouble them, but they are ignorant of history and human nature besides.
It is more a case of making allies with a common enemy. If modern religion disappeared, Paganism would immediately gain from it. We know this by looking back before Christianity emerged, and noting that human nature has not changed.
But Paganism is the bellwether of Naturalism’s demise – its miscarriage, really. If Naturalism could not dam up religion from the earliest days, it never had a chance.*
Why is this significant? The question is the answer.
That is, significance is the first handhold out of the physical realm. If physical objects can be imbued with meaning beyond their physical utility, then we are also engaging in a realm beyond physical activity.
Think of a flower, for instance. It has physical utility, a place in the natural order.
Now think of giving a flower. One is not offering the flower in order to pollinate another flower, or for ingestion, or for composting or anything else. Instead, the giver and the receiver both perceive an abstract (roughly, a spiritual) significance to the flower and the act of giving the flower.
This is what the naturalist could not prevent from happening, never could prevent from happening.
*The usual line is that humanity has sufficiently advanced, or will inevitably advance, such that religion will be seen for the fraud it is. They believe we will see Christianity like we now see Roman paganism.
As a matter of fact, the sword has another edge – if the Stoics and the Enlightenment could not free the world from the grip of religion, it is doubtful that anything else could. Rather, one religion comes to dominate another at any given point in time.