Some would say that Neanderthals were humans of a different kind, and I would support that.
The convention of biologists in English-speaking countries is to define "human" as any species in genus
Homo. This includes the more-or-less contemporaries
H. sapiens, neanderthalensis and
floresiensis, as well as the ancestral species
H. heidelbergensis and
gautengensis, and potentially an alphabet-soup of fossils that may or may not be other species and may or may not be in our genus.
This is a convenient categorization, since in addition to close genetic relationship that presumably would have allowed the species to interbreed (Neanderthals and
sapiens clearly did), it also limits the name "human" to apes with at least half of our cranial capacity of one liter.
To distinguish us from all other human species,
H. sapiens are referred to as "modern humans." Earlier ancestral species in other genera such as
Australopithecus and
Ardipithecus are called
hominids. Going back up the taxonomic tree to the next-lowest point at which other branches of the Primate order have survived, the two species of gorilla, the two species of chimpanzee and humans are called
hominins.
As to other evidence; I do believe that there are no artifacts or evidence to support the notion that supernatural belief existed before Homo sapiens, and certainly not Homo sapiens sapiens, bar Neanderthals which were themselves a separated (possibly), advanced branch and human in their own right. But due to the fact Neanderthals open up the possibility, can we say with one hundered percent certainty that "humans predate theism"? I think we can say "hominids predate theism" with more of a degree of certainty.
At least one Neanderthal grave has flowers in it. (After DNA analysis, Neanderthals are now considered a separate species.) And they had music; a large flute made from a mammoth tusk was found in Europe dating far beyond the arrival of our species.
Where is the line drawn between "Human" and "Animal"?
I don't support that dichotomy. Biologically, humans are apes, primates, mammals, chordates, deuterostomes, bilateria... and animals.
Is it possible that something we believe to have been an "Animal" could comprehend the idea that something made the world/environment/ecosystem said individual inhabited?
It's hard to imagine that the smaller brains of most other mammals could have accommodated the complexity of thought required to formulate these ideas. Dogs, for example, as bright as they are, have so little
time sense that the concept of something happening very far in the past or future is for all practical purposes incomprehensible. (This is why, if you want to have a serious discussion with your dog about something he did that you don't appreciate, you'd better catch him within about twenty-three seconds. After that, whatever it was has become part of the landscape.)
The psittacines (parrots and their relatives) and of course the cetaceans (whales and dolphins) have relatively large brains (in proportion to their body size, since a lot of brain tissue is dedicated to communication with sensory and motor nerves), so they may be able to contemplate these weighty issues. I don't know much about elephants, but they are smart, social, and have long memories, so perhaps they're in this same category.
I would suggest that theism is a dead duck without language to spread teachings and ideas so would agree that language predates theism. So we just have to figure out when higher-complex intercommunications began in hominids.
The Neanderthal skull has an indentation very much like ours where the speech center of our brain resides, so it's reasonable to speculate that they could have invented speech. This was not known when Jean Auel wrote
Clan of the Cave Bear so her Neanderthals communicate in sign language. But sign language is language, using our already well-developed hands and fingers instead of our amazingly complex vocal organs (our larynx is an anatomical nightmare, the reason we can't breathe and swallow at the same time like most mammals), and today two non-human species of ape have been taught to use it.
As to the timing of the invention of language, they thoughtlessly left us no recordings so we can only guess. An intriguing hypothesis offered by linguists is that spoken language was the key technology that allowed modern humans to migrate successfully out of Africa, after a few previous expeditions left evidence of their exodus but no descendants. It certainly makes sense that the enhanced ability to plan, organize and pass information from one generation to the next might have been the resource needed to survive in a region where everything was different. If this hypothesis is correct (we're still searching for that CD), then speech was invented before 60KYA, when the first group of San explorers made it all the way to Australia and left a few colonies along the southern coast of Asia.
If we say that less advanced hominids were more primitive and yet still "human" then the possibility is swaying in your direction. I suppose it comes down to where one draws the boundaries of definition (again). What is the standard definition of "Human"?
As noted earlier, all
Homo species, whose brain sizes are of the same order of magnitude.
Homo sapiens, "Man the wise." It's hard to be wise with a small brain.
