The evolution of rational spiritual animals on earth. Three evolutionary stages have been mentioned in this explanation of the origin of spiritual animals. The first was the evolution of animal societies of hominids; the second was the evolution of primitive spiritual animals; and the third was the evolution of rational spiritual animals.

Here is a brief review. (See the diagram of stages of evolution.) Although the first stage (stage 7) is just part of the radiation of primates, both subsequent stages require higher levels of part-whole complexity in the behavior guidance system than the previous stage. Each stage is predicted by the further relevant condition that a higher level of part-whole complexity enables the primary structure to control, though the evolution of primitive spiritual animals (stage 8) also involves a higher level of biological organization as well. The use of natural sentences evolves in hominid societies, because that makes it possible to generate social level behavior as the result of a shared intention in which different members make different contributions to a common plan. But since as population grows and resources become scarce, they use war to obtain energy, spiritual animals live in a dangerous world where another behavior guidance system is needed to make the momentous choice between war and peace. The use of psychological sentences evolves (stage9), because it makes explicit the reference to psychological states that is implicit in the input to the rational behavior guidance system. The choice between war and peace depends on the intentions of the other spiritual animals, and rational imagination enables them to represent psychological states as causes of behavior (and beliefs). The ability to infer the intentions of other spiritual animals from observations of the behavior of their members — that is, to see into their minds — makes it possible to choose between war and peace earlier and more reliably than primitive spiritual animals. Thus, these stages of evolution are inevitable, if evolution is the global regularity about change over time caused by how reproductive cycles add up in space over time, as we have found holds necessarily in a world of matter and space in time.

All three evolutionary stages are inevitable, but it is not clear from the data accumulated by paleontology and archeology which species are at which stages. Between hominids (stage 7) and reflective subjects (stage 9), there are linguistic subjects, or primitive spiritual animals (stage 8). The first and last of these stages are relatively clear. But it is not entirely clear when spiritual animals first evolved, and thus, neither is it clear when they first became rational.

If reason explains human nature, the third of these three stages, rational spiritual animals (stage 9), is represented by Cro Magnon Man (modern humans or Homo sapiens sapiens), because apparently nothing basic distinguishes us from them. Cro Magnon Man is the species that replaced Neanderthal Man (archaic humans or Homo sapiens) in Europe about 35,000 years ago. Not only are they anatomically indistinguishable from modern humans as far as fossils reveal, but judging by the wealth of artifacts that remain, ranging from finely chipped stone tools and weapons to jewelry and works of art, they also had a rich culture, like modern humans.

We have considered the possibility that Homo erectus had the use of a primitive language of natural sentences, but as we have seen, it is by no means required to explain what is known about them. And there is much to suggest that they were merely exploiting the limited capacity of animal cries and screams to serve as signs in coordinating behavior, comparable to wild dogs of Africa, except that they had new kinds of behavior make possible by structural imagination.

In archaic humans, such as Neanderthal Man, by contrast, there is evidence of a dramatic change in both the tools used and the capacity for verbal behavior. Flint tools and hafted stones indicate that archaic humans had a more advanced (Mousterian) culture, as we would expect of animals with the greater understanding of causal connections that comes with having a conception of states of affairs. There is also fossil evidence of changes in the larynx that suggest a much increased reliance on highly modulated sounds. Moreover, if archaic humans did have a primitive language of natural sentences, their capacity to coordinate behavior would explain why Homo erectus became extinct about the time that Neanderthal Man and other species of archaic humans showed up. That is, Homo erectus were the societies of hominids on which archaic humans preyed, before they took up war against one another.

Thus, it seems likely that that archaic humans were the first spiritual animals (stage 8). Given the ontological cause of revolutionary evolution, the replacement of Neanderthal Man by modern humans was inevitable, because Neanderthal Man would have to make choices about war and peace like animals, acting on the strongest immediate desire caused in the leader by instinctive or learned cues. Without the capacity for reflection, they could not see into the minds of other spiritual animals.

Neanderthal Man had occupied Europe since at least 200,000 years ago, but even though they had robust, muscular bodies, they were wiped out by slighter-bodied Cro Magnon Man within a few thousand years about 35,000 years ago. Warfare is an extremely strong form of group-level natural selection, and it would have given Neanderthal Man a great facility at the use of natural sentences. But if they were only primitive spiritual animals, they would be no match for the invaders, because without the use of psychological sentences, they could not figure out the intentions of Cro Magnon Man. On the other hand, Cro Magnon Man, as rational spiritual animals, could see into the Neanderthal mind. Thus, not only could they defend themselves against Neanderthal attack, but they could also intentionally deceive or trick Neanderthals, for they could understand the linguistic and other instinctive signs Neanderthals used to tell friend from foe and turn them to their own advantage.

It might be argued that Neanderthal Man and Cro Magnon Man cannot represent successive stages in the evolution of spiritual animals, because Cro Magnon Man could not have evolved from Neanderthal Man. There is some evidence (from their mitochondrial DNA) that modern humans had a common ancestor in Africa about 200,000 years ago or more, about the time archaic humans, such as Neanderthal Man, evolved. Furthermore, there is evidence of modern humans existing side by side with Neanderthal Man (archaic humans) in the Middle East some 90,000 years ago, long before their invasion of Europe, and the remnants of their technology at the time indicate roughly the same level of culture as Neanderthal Man.

These objections are not, however, decisive, because it is not necessary for Cro Magnon Man to have evolved from Neanderthal Man for them to represent a later stage of evolution. There were probably several species of archaic humans in existence 200,000 years ago, not only Neanderthal Man, but also other species of spiritual animals, and one of those others could have been the ancestors of modern humans. Since they must all have had the use of natural sentences, what made the ancestors of modern humans different may have been something about their neurological mechanism for using natural sentences that made it easier for them to try out the higher level of part-whole complexity required for the use of psychological sentences. Thus, the somewhat greater brain size of Neanderthal Man (about 1500cc on average, as op­posed to 1350cc for modern humans) may indicate, not greater intelligence, but just a more cumbersome mechanism for using natural sentences.

Furthermore, it is possible that reason had already evolved 90,000 years ago, when both modern humans and archaic humans existed side by side in the Middle East, because this was during the last great ice age. The robust bodies of Neanderthal Man were well adapted to the harsh climate in Europe, whereas modern humans, with slighter bodies, were confined to the more temperate region of the Middle East. Thus, the greater capacity of rational spiritual animals to make choices about war and peace may have been used almost exclusively to kill Neanderthal Man only when Neanderthal Man ventured into their more energy-rich territory.

Indeed, the presence of Neanderthal Man may have enabled modern humans to live at peace with one another, because at those times when resources became scarce and war was a means of expanding the supply, modern humans could increase the territory from which they gathered energy by waging war against archaic humans, rather than against other modern humans. Modern humans may even have hunted archaic humans for food. In any case, the balance between archaic and modern humans could have been maintained for many thousands of years, because as long as the ice age continued, modern humans were unable to invade very deeply the territory occupied by Neanderthal Man. Thus, their radiation would have been stymied, like mammals who could not dislodge dinosaurs from the rich ecological niches to which they had become well adapted.

This would explain why Cro Magnon Man replaced Neanderthal Man suddenly 35,000 years ago, for there was a brief respite from the last great ice age at that time, which lasted for a few thousand years. The change in climate enabled modern humans, for the first time, to overcome the scarcity caused by their population growth by invading Neanderthal territory, and their greater skill at making war meant the extinction of Neanderthal Man.

That is, it would be analogous to the extinction of the dinosaurs. Although dinosaurs were so well adapted to their energy-rich ecological niches that they were invulnerable to invasion by mammals, the impact of an asteroid changed the environment so radically that dinosaurs and mammals had to complete in a new environment, and the inherent superiority of subjective to telesensory animals made it inevitable that mammals would replace the dinosaurs. In a similar way, Neanderthal Man was invulnerable to replacement by modern humans until a break in ice age occurred and modern humans could take advantage of their inherent superiority to invade Neanderthal territory and replace them. Then, when the ice age returned a few thousand years later, Neanderthal Man was already gone, and modern humans could learn how to survive in the colder climate without competition from archaic humans. On this account, therefore, the sudden appearance of Cro Magnon Man in Europe about 35,000 years ago would be just another instance of catastrophic changes “shaking out” the natural kinds of organisms according to their inherent superiority.

Cro Magnon culture differed from Neanderthal culture in just the ways that we would expect reflective spiritual animals to differ from primitive spiritual animals. As rational animals, they could not only see into other minds, but also reflect on the causes of their own conclusions about how to behave and what to believe in the process of drawing them. Thus, instead of a language of just natural sentences for coordinating behavior and passing technology on by imitation, the culture passed down from generation to generation by Cro Magnon Man was an accumulation of arguments about what to do in certain situations and what to believe (as will be explained more fully in the next section). And their culture would reflect the danger of living in a world where war was always possible.

Once Neanderthal Man was no longer around to prey on, it was inevitable that modern humans would resort to war against one another, since the growth of their population caused scarcity and they knew the value of war from battles with Neanderthal Man. But when reflective spiritual animals turned the weapon of war against one another, they had to determine, as primitive spiritual animals did, whether other groups they encountered were of the same tribe, for there were normally at least some other groups with which they had friendly, in-group relations. Tribal membership was the main way of telling whether other groups they encountered were one of Us or one of Them in choosing between war and peace, but tribes of reflective spiritual animals were based on sharing a culture of accumulated arguments, including legends and myths, rather than simply use of the same language. But when they decided to treat the other group as part of their tribe, they made themselves vulnerable, and thus, there was always the danger that other groups were gaining an advantage over them in war by pretending to share their culture. This was a trick that had probably worked well against Neanderthal Man. By pretending to speak their language of natural sentences, primitive spiritual animals would have been deceived into treating their enemies as friends. More subtle forms of deception might be used against other rational spiritual animals.

The danger of war would explain, therefore, the sudden appearance of highly refined artifacts, such as the ivory figures of animals which were apparently worn as jewelry, after Cro Magnon Man invaded Europe. It would provide credible evidence of their tribal membership. Groups in a tribe might identify with different kinds of animals, and thus, tribal membership could be represented by groupings of animals and, within tribes, nomadic bands could keep track of their relationships to one another by passing down stories about the animals with which they identified from generation to generation. Groups could give credible evidence of which group they were and which tribe they belonged to by the kinds of animals depicted in their jewelry. The ornaments were credible, because the art involved in creating them made it too difficult to fake them. Thus, highly refined works of art were good evidence about one another’s tribal membership, and that made it easier for groups from the same tribe to establish trust. Considering their value in making reliable choices about war and peace, there was a strong selection pressure at the group level, favoring skill at art as well as facility in the use of psychological sentences to reflect on the reasons for their behavior.

In other words, the lack of highly refined ornaments and ivory figures among the remnants of modern humans in the Middle East around 90,000 year ago does not necessarily mean that reason had not yet evolved. Their level of culture is what might be expected of rational beings, if warfare was reserved for use against the easily recognized archaic humans that were always on the frontier of the territory from which they were excluded by their slender bodies. Under the circumstances, all modern humans may have been able to treat one another as part of the same tribe.

What ontological philosophy implies about the evolution of reason is, therefore, consistent with what is known about the ancestry of human beings on Earth. Indeed, it accounts for those facts better than the theories currently being discussed by archaeologists. But it should be emphasized that ontological philosophy would not be refuted by evidence that contradicted the interpretation of the archaeological evidence that has been sketched here. It is also compatible with the hypothesis that modern humans in the Middle East some 90,000 years ago simply had not yet evolved the use of psychological sentences. It is, however, an empirical question which species on Earth are the ones that represent those stages. All that we know on ontological grounds is that there must have been a stage of evolution between societies of bipedal hominids and rational animals, because reason can evolve only in primitive spiritual animals, which already have the use of natural sentences. No one denies that societies of hominids are a late phase in the radiation of higher primates (stage 7). Nor does anyone doubt that Cro Magnon Man was a form of modern humans, and if the nature of reason as explained here accounts for human nature, Cro Magnon Man must represent the rational spiritual stage of evolution (stage 9). Thus, it remains only to decide which species represents primitive spiritual animals (stage 8). On the basis of what is currently known about our past, I have suggested the reasons for believing it is represented by Neanderthal Man and other archaic humans. But new evidence might justify assigning this role to another species.