Cultural evolution at the rational spiritual stage. Gradual evolution during the rational spiritual stage gives individual humans greater facility in using psychological sentences, but the change that inevitably occurs during this stage is not limited to traits that depend on the biological behavior guidance system.

The use of a language with psychological sentences transforms linguistic interactions into an exchange of arguments. As variations on arguments are tried out more or less randomly, the many individual judgments about which of competing arguments to accept is a rational selection from among them, and so the arguments accumulated in a spiritual animal and passed on from generation to generation evolve. Culture undergoes a gradual change in which arguments start off simple, uniform and weak and become increasingly complex, diverse and powerful.

In other words, cultural evolution is a form of reproductive causation contained within spiritual animals. But since it involves the rational selection of random variations on arguments, culture tends to discover the true, the good and, as we shall see, the beautiful.

In order to show that cultural evolution is part of the rational spiritual stage of evolution, I will explain how cultural evolution is a form of reproductive causation contained by rational spiritual animals. But instead of trying to trace the entire course of cultural evolution, I will show how the natural perfection toward which rational level culture evolves inevitably includes three dichotomies that divide arguments into four groups, without only religion to paper over the differences among them.

Reproductive causation contained by rational spiritual animals. Cultural evolution is a reproductive global regularity that occurs in  spiritual animals. The reproductive cycles and the space in which they add up over time are constituted by rational spiritual animals. Thus, the essential nature of rational spiritual animals contains the ontological cause of this gradual evolutionary change. It depends on the relationship between their social and cultural aspects.

To recapitulate, reason evolved in spiritual animals that already had the use of a primitive language. Language is what gives a group of multicellular animals the structural cause needed to coordinate the members’ behavior as social level behavior, and made spiritual animals a new form of life on the social level of biological organization. But language worked so well, as we have seen, that it eventually forced spiritual animals to choose continually between war and peace. That choice was to made more reliably with the use of psychological sentence evolved, but that made the individual members reflective, so that their behavior was caused by reasons. Reason became the system for guiding not only the behavior of the spiritual animal, but also individual behavior.

The unique way that the individual and social levels of biological organization are combined in rational spiritual animals makes it possible for reason to evolve more and more power to control conditions in the world. The structural cause of social level behavior in spiritual animals is a special kind of material structure which I am calling a “spiritual structure.” A spiritual structure is actually two different kinds of structures bound together by the use of language, one under the social aspect and the other under the cultural aspect, and both are structures of the spiritual animal as a whole.

The structure under the social aspect is the fact that language-using animals stick together and are in continual interaction (including linguistic interaction) as parts of an organism at the social level.

The structure under the cultural aspect includes all the linguistic structures generally shared by members and which individual brains born into the spiritual animal normally acquire, including the language itself and the set of beliefs and intentions that come to be shared by its members because of the various linguistically mediated ways they normally interact.

Since the structures under these two aspects of the spiritual animal are different, they can interact with one another.

Thus far, we have focused on how the linguistic structures under the cultural aspect affect the social aspect. In primitive spiritual animals, the use of language distributes plans of social level behavior to the members in a way that enables each individual to know what he is supposed to do, and that makes it possible for the social level behavior of spiritual animals to act on other objects in space (or organize interactions of its own members as social structure). More generally, language enables the members to share beliefs and intentions as a worldview, and culture generates customs, institutions and other regular aspects of social level behavior.

There is, however, an equally important effect that the structure under the social aspect has on the cultural aspect, because the linguistic interactions can affects the content of the linguistic representations being exchanged among the members and, thus, their beliefs and intentions. Though this effect already occurs inefficiently in primitive spiritual animals, it becomes, with the evolution of psychological sentences, a normal part of almost linguistic interactions. In rational spiritual animals, as we shall see, the linguistic representation exchanged include arguments (that is, conclusions about how to behave or what to believe that come together with reasons for them), and such an exchange constitutes another contained form of reproductive causation, this time, one in which the arguments accumulated as culture evolve in the direction of natural perfection for arguments of its kind, which is to discover the true, the good and the beautiful, albeit within certain inherent limits.

In primitive spiritual animals, the social aspect already has important effects on the cultural aspect. The linguistically mediated interactions among the members is what distributes the plan among the members in a way that assigns them different roles to play in social level behavior. But linguistic interactions were not necessarily as one sided as that model suggests.

Guiding social level behavior was not necessarily just a matter of following the leader’s instructions. Members could also pool their knowledge of the current situation, since everyone could speak natural sentences as well as understand them. The context and manner of the utterance would make it clear whether the sentences were meant to assert a description of what is, to ask about a state of affairs, or merely to present a possibility to be taken into consideration.

Members could also pool their understanding of efficient causation in the natural world, since naturalistic imagination gave them all the capacity to see states of affairs as causes and effects. Thus, spiritual animals could accumulate increasingly complicated techniques for controlling natural processes. For example, instead of carrying fire with them, they could acquire the skill to start fires when needed.

Finally, since each member could understand how the leader’s plan was supposed to attain goals set by their own desires, their willingness to follow his instructions would tend to depend on whether it made sense to them. The adoption of a plan for the immediate situation would the result of a linguistic interaction between the leader and the members.

In rational spiritual animals, however, this effect of the structure under the spiritual animal’s social aspect on its cultural aspect becomes much stronger, because context is no longer needed to indicate the roles that spoken sentences are meant to play in determining beliefs and behavior. The use of psychological sentences enables them to represent psychological states as causes in the process of guiding behavior (or determining beliefs), and that makes it possible for speakers, in their attempt to agree about what the spiritual animal should do, to make explicit what roles they mean their sentences to play. A leader is less important to the spiritual animal’s behavior guidance system , because every member can make arguments at any time that everyone can understand.

The exchange of arguments in spiritual animals is the ontological cause of cultural evolution. Arguments are like “organisms” that reproduce as one member of a spiritual animal makes the argument and another member accepts it as a cause of what she believes or does. Such reproductive cycles add up in the “space” of spiritual animals over time to a form of natural selection. They cannot go on reproducing for ever, because there are only so many members of a spiritual animal. But since what determines which one’s go on is, as we shall see, rational selection, the arguments accumulated as culture in a spiritual animal gradually evolve in the direction of natural perfection for “organisms” of their kind, that is, arguments that discover the good and the true.

In order to show the inevitability of this global regularity within rational spiritual animals, let us consider the nature of arguments and the nature of rational selection. That will enable us to see why gradual cultural evolution is inevitable.

The nature of arguments. Though the original function of reflection was to control a condition affecting the reproduction of whole spiritual animals, it is the members who had the faculty of rational imagination, and so it was inevitable that individual subjects would also use reflection to see into one another’s minds and to understand the causes of their own behavior.

Self-reflection. Reflection is self-reflective when psychological sentences are used to predicate psychological states of oneself, instead of another subject. It may be, in the first instance, just a way of monitoring one’s beliefs and desires, which enables one to report how things seem, that is, that one has a certain belief, rather than just making an assertion about the world. Or to recognize that one has a desire, rather than just asserting that something is good. The faculty of rational imagination is required for self-reflection, because that is what enables one to see psychological states as psychological states, rather than simply to have them.

The developmental stage at which children acquire the use of a faculty of rational imagination has been identified in children.^[1] It is manifested as the capacity to think about subjects as subjects. Until about the age of three, children cannot distinguish how something appears from what they believe it is. When they mistakenly believe that a molded piece of wax is an apple and they are shown their error, they correct their belief, but they insist that they always thought it was a piece of wax and assume that everyone else will also see it as a piece of wax. By the age of four or five, however, children can understand that it appears to be a piece of fruit, even though they realize it is not, and they expect that seeing it will cause others to form mistaken beliefs about it. The difference is that the older child has the capacity to think about people as forming beliefs because of how things appear in perception, and thus as having beliefs that may differ from what really exists. To be sure, three-year-olds are already able to use such words as “see” and “believe.” But they assume that what is seen or believed is always the same as what really exists, as if there were no distinction between appearance and reality.

The cognitive development of children recapitulates the change that occurred in the evolution of primitive spiritual animals into rational spiritual animals. A whole new range of facts about the world comes into view with the capacity to think about subjects as having psychological states. They include facts about desires as well as beliefs. Instead of simply having desires or seeing objects as desirable, the reflective subject can think of individuals as having desires, whether or not the objects are desirable or attainable, and see their behavior as being caused by them. That is, after all, what was crucial in the original function of reflection, making choices about war and peace.

Self- reflection is not, however, just the capacity to monitor one’s psychological states. In representing one’s psychological states to oneself as psychological state, self-reflection represents them as causes, and that changes the nature of the causes of one’s behavior and beliefs.

Rational imagination enables subjects to see the difference that having any perception, belief, desire or intention would make in the choices they make (or on the beliefs they form). By seeing actual psychological states against the background of what is possible, subjects are able to represent the causes of their own behavior (and beliefs) as causes of their behavior in the very process by which they are causing behavior.

But as rational spiritual animals evolve, that self-reflective power becomes a integral part of the animal behavior guidance system, so that reflection on the causes of one’s behavior (or beliefs) makes a difference in what one does (or believes). That is, the causes of behavior become causes that are represented as causes of behavior as a causally relevant part of the process of causing behavior. That is how they earn the special name. “reasons.” Though reasons are still efficient causes of behavior, their power to cause behavior comes to depend on them being represented as causing behavior.

Reasons. The transformation of animal causes of behavior into reasons makes animals more powerful, because when the causes of behavior must be represented as causes in order to cause behavior, the mechanism that represents them (the linguistic system of representation) can control behavior. That is, it brings the animal causes of behavior under the control of a higher level behavior guiding process. That higher order process is located in the linguistic hemisphere of the forebrain, and we have already seen how the linguistic system of representation acquired control over the causes of behavior.

Even hominids had a desire to submit to the leader, which derives from the dominance hierarchy of animals. But with the evolution of language, the desire to submit to a leader became the desire to do what the leader said, that is, to conform one’s behavior to a linguistic representation of it. Thus, when the use of psychological sentences transformed the members into reflective subjects, the desire to submit to a leader became a desire to submit to reason (that is, to act only when the causes of behavior are represented linguistically in a certain way in the process of causing behavior).

This evolutionary transition is recapitulated in human beings at adolescence. Though the child submits to the plan imposed by her parents, a radical change takes place at puberty. The adolescent starts to take control of his own behavior, often rebelling against parental limitations, because what is causing his behavior are now causes represented linguistically in a different way, namely, as the conclusions of practical reasoning. The burden of being responsible for his own choices takes the form of worries about his identity. This is the process by which the language-based power of reason, which is located in each individual, takes over control of individual behavior.

As will be explained more completely later, this rational control of behavior gives the individual increased power to control relevant conditions. It is a kind of “autonomy” that subjects have because they are rational, or the “autonomy of reason.”

Once the reflective subject has the ability to act on the results of such a reasoning process, psychological states are not merely causes of behavior on which the subject can reflect, but rather a new kind of cause of behavior. For example, though desires are seen as causes of one’s behavior, the capacity to represent the causes of one’s behavior as causes in rational imagination makes it possible to reflect on all one’s desires, including those that will be felt only in the future or under other circumstances. Thus, it is possible to figure out the best way to behave in, say, a series of situations to satisfy them all. This is a form of practical reasoning, and in rational subjects, reason wrests control of behavior away from the animal causes of behavior (mainly, desires), because the desire to submit to reason enables the intention formed by practical reasoning to generate behavior even when it is opposed by currently strong animal desires. Rational subjects can, for example, delay gratification. Nor is this the only way reason guides behavior independently of strongest (other) desire at the moment, for as we shall see, reason even enables the subject to pursue goals that do not control conditions that affect his own reproduction and to do what is good for the spiritual animal.

Reasons can also change the way that beliefs are formed. Beliefs are most commonly caused by perceptions. But beliefs are all connected (because the objects they are about are all related in space and it is possible to call up the states of affairs in which they are involved from the map of one’s territory built up by spatial imagination). Furthermore, episodic memory for particular past events (another form of the capacity to record memory groups in sequences) sometimes makes it possible to reflect on the perceptions that caused particular beliefs. Thus, by reviewing the reasons for one’s beliefs, comparing the relevance of current perceptions with past perceptions in causing beliefs, and the like, it is possible to correct errors and make more reliable judgments about what is true. For example, by knowing which beliefs were caused by perceptions in the past, it is possible to dismiss current perceptional illusions or to resolve ambiguous perceptual input.

Reasons and conclusions. When behavior and beliefs are caused by reasons, the social aspect of the spiritual animal has a much more powerful effect on the cultural aspect, because the linguistic representations being exchanged can contain conclusions together with reasons for them, that is, arguments.

This is the change in the behavior guidance system of the spiritual animal that was suggested above by contrasting the primitive spiritual animal’s use of a leader to distribute a plan publicly to all the members and a processes in which members come to agree about which plan is best by arguing with one another about it. The increased power of linguistic interactions to coordinate the members’ behavior comes from how the use of psychological sentences frees reasoning about what to do (or believe) from dependence on the context provided by a leader.

This change resembles the earlier transition from nomadic bands of hominids to primitive spiritual animals, where the increased power of linguistic interactions to coordinate the members’ behavior came from how the use of natural sentences freed the primate cries and screams from dependence on context for their meaning. In both cases, context was no longer needed to align imagination in different animals, because verbal behavior included grammatical markers that represented how the listener was to operate his imagination. Not only was a leader not needed, but members could be drawn into agreement anywhere about how to behave (or believe) in any situation. That increased the power of spiritual animals in a more far reaching way, because eliminating the need for context in arguing made it possible for arguments themselves to accumulate as part of the culture and, thus, for culture to evolve by rational selection.

Arguments are simply conclusions about what to do (or what to believe) that come together with reasons that recommend them, that is, with other propositions asserted as causes for accepting the conclusions.

The mechanism by which reflective subjects can consider arguments is implicit in their ability to use psychological sentences. The behavioral schema for a psychological sentence generates covert nonverbal behavior that operates on images in the sensory input system. It not only constructs a naturalistic (or psychological image), but also represents it as having a causal role, such as a belief or desire, and predicates that psychological state of a subject. The psychological state is seen against the background of what is possible by rational causation, such as the roles it might play in causing behavior (or belief), and thus, the psychological linguistic act can be used to predict or explain what the subject will do (or believe). This rational explanation can then be expressed in over verbal behavior. For example, “Joe went to the ridge, because he believed that the deer were in the valley beyond and he wanted to check on them.”

Arguments are a modification of this ability to understand rational-cause explanations. When considering the reasons for a conclusion, it makes no difference which rational subject the psychological states are attributed to. Behavior guidance systems all work basically the same way. Everyone shares much the same background beliefs as their worldview. And they are all moved by the same kinds of desires. Hence, the reference to a particular subject as the grammatical subject is generally suppressed in formulating arguments. Thus, arguments are like anonymous rational cause explanations (or predictions).

It is still necessary, however, to include verbs of propositional attitude (or grammatical markers for them) in order to refer to the proposition, rather than what the proposition represents, and to indicate its (causal) role in the argument. For example, “In order to check on the deer, go to the top of the ridge, because they can be seen from there.” The argument must enable the listener to reconstruct the inference in her own rational imagination, and in more complicated arguments, the conclusion may depend on imposing several psychological states on rational imagination simultaneously, or there may be a series of conclusions. Thus, some propositions may be referred to explicitly as reasons for other proposition, or the inference may be indicated by, “and thus” or “because.”

Rational selection. On any given issue, however, there may be arguments for different conclusions. A judgment must be made about which is correct, and it is made by each individual. That is the rational selection of arguments, and as we shall see, that is why the general exchange of arguments among members of a spiritual animal gives rise to the gradual evolution of culture by rational selection.

Judgment. According to this explanation of the nature of the reflective level of neurological organization, each individual is able to judge the correctness of any argument about what to do or believe in any situation, because each has a worldview in which to test its coherence with other beliefs and intentions.

Each individual has a more or less complete set of beliefs about the natural world, because beliefs are all ultimately about objects located in space, and since space is whole, they must all be related to one another in the subject’s mammalian map of his territory. But that is not only to have beliefs about the locations, geometrical structures, and properties that they have been perceived as having, but also beliefs about how they can change locations and how they would interact (since they are objects represented in spatial and structural imagination). And in naturalistic imagination, the worldview also includes the states of objects in space and how they are involved as causes and effects in the natural world. And corresponding to the endurance of the natural world through time, their view of the natural world is a history that includes whatever they remember about the histories of objects in their territories.

Each individual also has a more or less complete set of beliefs about the subjects in their world. Subjects are also objects in space, and though their behavior is explained by their psychological states (as reasons), all the beliefs and intentions by which the behavior of members of their spiritual animal is explained would have to fit together as a whole both in space and over time. Though there is more to be said about it, their worldview would include a social world as well as a natural world, each explained in its own way.

Finally, each individual would has more or less complete set of intentions about what to do in any situation, both at the individual level and regarding the behavior of the spiritual animal as a whole. In addition to any particular plans they may have, it would include intentions about how to choose among goals when conflicts arose. In short, they have certain values.

Though such a worldview is worked out in detail only as far as it was useful or questions about it had to be handled, there is a coherence about the beliefs and intentions it contains, because everything is seen in rational imagination as part of a single world, a natural world of objects in space, including subjects as a special kind of object, where certain basic regularities hold. The worldview is the background against which arguments are tested.

Merely fitting together comfortably with the worldview is all that was required to accept new beliefs about the world, if there is some reason to believe them, such as perception or reports of perception. To report, for example, “I saw deer in the valley,” is to argue, in effect, that it is true for a certain reason, and unless there is some reason to distrust the reporter, it is a good argument. .

Arguments whose conclusions contradict one’s worldview in some way require reasons that can dislodge already established beliefs. For example, in addition to some positive reason for holding the new belief, there may be reasons for doubting the grounds of the old belief. By reflecting on her worldview, it is often possible to surface the grounds for any particular belief by imposing the alternative on imagination and seeing what else would have to change. If those grounds are not themselves well grounded, she may be convinced by the argument.

In some cases, it is possible to dislodge current beliefs by showing that the new belief is entailed by other beliefs that the subject already holds because of regularities to which the subject is committed by the very structure of rational imagination or which are firmly established for other reasons. Or in more complex examples, whole sets of beliefs about some aspect of the world is challenged by an alternative set, and the judgment about which is correct depends on which set was simpler and fit into the background more completely.

The interests of reason. Though each individual judges which arguments to accept, it is not just a whim. Rational subjects judge arguments in the same way, and making rational selection selection in the interest of reason.

Since arguments are tested by their coherence with one’s worldview, their acceptability depends on whether they make one’s worldview more coherent as a whole. It is possible to tell which argument results in the most coherent worldview, because arguments are considered in rational imagination, where the actual (or proposed) is seen against he background of what is possible. Imagination connects all one’s beliefs and intentions together, and so the judgment about whether to accept an argument is ultimately an aesthetic judgment. To use imagination to tell whether one set of beliefs or intentions is better than another is to judge arguments by the beauty of accepting their conclusions, that is, by whether it would be unique among the alternatives in basically the same way as natural perfection itself, that is, making the most out of the least.

Truth. Though the means of judging is coherence, that does not mean that beauty is the goal of reason. Since the foregoing examples are theoretical arguments, that is, arguments about what to believe, the goal of reasoning is truth. The conclusions are accepted because it seems that the propositions correspond to the world. That is how the goal appears to rational subjects, because arguments for believing certain propositions are judged by whether the states of affairs they represent are part of the world as represented in perception and, more broadly, in one’s worldview.

Goodness. There are also arguments about what to do, and in the case of practical arguments, reasons’ goal is to know what is good. But the judgment about whether to adopt the proposed intention urged by the reasons offered depends on how the intention fits together with established intentions about how to deal with the relevant situations. Coherence in this case depends on the intention fitting together with the whole set of intentions, including policies and plans, for dealing with all the situations that arise over time in leading the life of a reflective subject as part of a spiritual animal, and thus, it also requires a judgment based on overall coherence. At this stage of evolution, the intentions are mainly caused by their desires, though as we shall see, that may not be recognized. And since plans for satisfying all their desires depend on an aesthetic judgment, about how they fit together, rational subjects often pursue goals that are good for reasons other than affecting their own reproduction. But established intentions, or values, by which the conclusions of practical arguments are judged are usually seen at the rational spiritual stage as fixed by ancestors, gods, or nature.

Beauty. Truth and goodness are, therefore, interests of reason. But since the truth and the good are judged by rational coherence, reason necessarily has an inherent interest in beauty as well. That is the means that reason uses to judge them, though it may not be recognized as an aesthetic judgment. But the rational interest in the beautiful does guide reason explicitly in other ways, for example in productive reason, that is, in making products that are beautiful, including the fine arts. Since beauty is the same kind of unique optimum as natural perfection, which marks the direction of evolution, there is a sense in which the ancient Greeks were correct in holding that art is the imitation of nature. Art is artificial perfection.

These interests are the interests that rational subjects recognize they are pursuing by reasoning about what to believe and what to do. But given the essential nature that reason has as the behavior guidance system that evolves at the rational spiritual stage, we can see that these interests are actually aiming at maximum holistic power for rational beings, that is, that they contribute to natural perfection.

Though rational subjects may see truth as a correspondence between their linguistic representations and appropriate aspects of the world, they do not understand the nature of the correspondence completely. They take the world to be what appears to them in perception, and thus, they are thinking about a relationship between representations in rational imagination and representations caused by sensory input. In fact, the correspondence that makes the true holds between both of those kinds of representation and aspect of the natural world. But judging the truth of beliefs by the correspondence that seems to hold at the rational spiritual stage usually still has the effect of discovering the actual correspondence, which contributes to the power of the behavior guidance system to guide behavior.

Likewise, rational subjects at this stage see the good as something about what is judged to be good, and thus, once again, reason’s interest seems to be correspondence too. But since the only explanations of the nature of goodness at this stage are religious, it is not clear what practical conclusions must correspond to. From the perspective of ontological philosophy, however, we can see that what correct conclusions about how to behave correspond to is what contributes to the natural perfection of the whole of which they are part. This is not as straightforward as it may seem, for as we shall see, the pursuit of goals may contribute to the natural perfection of rational beings even though they do not control conditions that affect their own reproduction. Because of the autonomy of reason, as we shall see, pursuing goals that are good for other reason, or “optional goals.” is part of the natural perfection of rational beings.

Because rational selection is made by maximizing the coherence of one’s worldview (including intentions), the true and the good are recognized by their beauty in the faculty of imagination. But from our ontological perspective, we can see that even judgments about the beautiful are correct in virtue of corresponding to an aspect of the world. In this case, it is correspondence to natural perfection itself, that is, the state that makes the most of the least. Such optimal states stand out in rational imagination, because that is the ability to see them against the background of what is possible.

Arguments as reproducing organisms. The capacity to argue about anything anywhere, with individuals judging for themselves what is true, means that the linguistic interactions in a spiritual animal constitute a new, contained form of reproductive causation. In this case, what evolves is culture, and it evolves in the direction of knowing the true, the good and the beautiful.

Evolutionary change, in general, is a global regularity whose ontological cause is reproductive cycles and how they add up in space over time. What evolves are material structures that go through cycles in which they not only reproduce themselves, but also do some kind of non-reproductive work. But since evolution depends on a natural selection from those material structures, there must also be variations on them that do different kinds of non-reproductive work, though they all reproduce in the same way, and such variations must continually be tried out randomly. A selection is made by success in reproducing. A selection must be made, because eventually it is not possible for all of the material structures to reproduce. But since which material structures succeed depends on the kind of non-reproductive work they do, evolution is inevitably change in the direction of reproducing structures whose non-reproductive work controls conditions that affect their reproduction.

In the case of biological evolution, the reproducing structures are organisms (or proto-organisms). They impose natural selection on themselves by their own reproduction, because their population increase causes a scarcity of the resources (free energy, if nothing else) in the region needed to go through reproductive cycles. And they evolve in the direction of greater power, because those random variations whose non-reproductive work is best able to promote their reproduction under those conditions are more likely to succeed in reproducing.

We have already encountered one contained form of reproductive causation in tracing the course of evolution. Neurological development is the evolution of behavioral schemata in individual brains by reinforcement selection, and as we have seen, it is change of the brain’s memory groups of neurons in the direction of behavioral schemata that internalize the regularities involved in spatial causation, structural causation, and efficient causation, as well as the words and grammatical structures of natural languages themselves.

Neurological development is, however, only the first the three such contained forms of reproductive causation. The second is cultural evolution by rational selection, and as we shall see, the third is economic evolution by capitalist selection. In each case, evolution is a global regularity caused by how cycles of reproduction add up over time in space, or in the “space” provided by some evolved structure  (respectively, the brain, a spiritual animal under its cultural aspect, and under its social aspect).

In the case of cultural evolution, the “reproducing structures” are arguments. Arguments can reproduce, because they can be expressed in overt verbal behavior, making it possible for listener who understands them to be convinced by them. That is, they reproduce themselves in the brain of other members of the spiritual animal. But reproduction is not complete, unless the listener not only understands the argument constructed in rational imagination, but is also convinced by it, because the non-reproductive work of an argument is its effect on how the individual behaves in certain situations or what she believes on certain topics. ^[2]

Random variations on arguments are introduced in various ways. Sometimes reproduction is not perfect, and the argument tried out in the new brain’s imagination is different from that of its proponent. Since they are constructed in rational imagination, variations may be tried out by accident or when trying to think about something else. Dreaming may play a role in generating random variations on arguments, since arguments are constructed by linguistic behavioral schemata and, as we have seen, the function of dreaming in mammals may be to sort out and reassemble parts of behavioral schemata involved in satisfying desires. New arguments can also be introduced when one spiritual animal encounters another, by a process of cultural diffusion. And some variations are likely to be tired out as all the arguments accumulated as the culture of a spiritual animal are passed to the next generation in the process of enculturation.

What corresponds to species of organisms are kinds of arguments. Arguments are differentiated by the situations to which they apply, though there are two classes of situations, one class involving the choice of what to do in the situation, and the other the decision of what to believe on some topic. Thus, arguments of each kind are like a species adapting to its ecological niche, and random variations on each kind of argument compete with one another in each ecological niche, like members of a species with different traits.

As arguments go through reproductive cycles, some reproductive cycles must come to an end. Each brain contains a full set of ecological niches for arguments, at least, in principle, because each individual faces all the situations in which a choice must be made about what to believe and what to do, if only in imagination. But there are only so many brains in the spiritual animal into which they can reproduce themselves. Thus, arguments impose a natural selection on themselves by their own reproduction, in much the same way that population growth makes resources scarce in biological reproduction, because as an argument reproduces into one brain after another, it fills the ecological niche for arguments of its kind. When no member of the spiritual animal lacks a belief or intention for the relevant situation, its reproductive cycles come to an end.

Given the scarcity of brains into which arguments of any kind can reproduce means that variations on arguments of each kind are competing to control the behavior of individuals in each situation. Variations on arguments can be tried out, even when every member already has a more or less complete worldview, because new arguments can be considered in rational imagination, for example, when one member makes the argument to another. To be selected, however, the argument must change the subject’s intentions (or beliefs). That is possible, because arguments include reasons that may dislodge the intentions or beliefs that already fill the relevant ecological niche. Success in reproducing depends on the rational subject’s judgment about which conclusion fits together more coherently in his worldview. That is, natural selection is by rational selection.

Gradual evolution of rational level culture. This is a form of reproductive causation, though it is contained within and sustained by rational spiritual animals, and thus, the arguments accumulated as culture should evolve gradually in the direction if maximum holistic power. As arguments are exchanged in spiritual animals, random variations on them are tried out, and there is a rational selection from among them imposed by the judgment of its members. It is a global regularity because it is a change in the arguments that are accumulated as the spiritual animal’s culture, and what is regular is that they tend to change in the direction of greater power to control the conditions that affect their reproduction. Since the reproduction of arguments depends on their making the subject’s worldview more rationally coherent, culture changes in the direction of discovering the true, the good and the beautiful, which is the source of the power of reason in guiding behavior.

Cultural evolution is not, however, biological evolution. The material structures going through reproductive cycles are just arguments that are expressed verbally by public linguistic representations and can be constructed in rational imagination, where they cause the brain to make an inference, from premises to conclusion. Their rational selection depends on whether accepting them as sound results in a more coherent worldview. Thus, cultural evolution has some unique features and some special limitations.

Like any stage of gradual evolution, arguments start off simple, uniform and weak, and as they evolve by reproductive causation, they become increasingly complex, diverse and powerful. In general, power is likely to increase, because the argument accepted for any given situation is likely to be closer to the truth than the others completing with it. And as situations calling for a choice about what to believe or intend are distinguished from one another, the arguments accumulated as culture become more diverse. Before long, therefore, a worldview evolves with beliefs and intentions for all the relevant situations.

Arguments do not, however, become complex in the same way as reproducing organisms in biological evolution, because arguments are not independent of one another at the ecological level. The ecological niches for arguments are the situations calling for choices about what to believe or intend, and there are similarities as well as differences among such situations. The reasons that hold in one situation are likely to hold in the others that resemble it, and since arguments must often dislodge established beliefs and intentions in order to be rationally selected, arguments that take account of such similarities are more likely to be accepted.

Discovering the true and the good is not, therefore, just a matter of accumulating beliefs about particular facts and making choices about how to behave in particular situations. It also includes the discovery of principles covering entire ranges of situations, uniting the arguments for them. Principles tend to become more general as rational level culture evolves. At a relatively early phase during the rational spiritual stage, for example, principles would evolve to decide which direction is south, where the deer have gone, what caused someone’s illness, who committed the crime, how to avoid hazards of weather, etc. And such principles become subsumed under more general principles as culture evolves.

In more advanced cultures, therefore, whole armies of arguments, with several echelons of command, may confront one another in the battlefield of linguistic interaction within a spiritual animal. There would then be profound theoretical disputes, because both armies, each with many individual arguments serving under a different set of principles, would deal with the same range of situations. Individuals would have to judge which theory would make their world views more rationally coherent, and the disputes may be so deep and global that there is no obvious grounds for choosing between them.

In less disputatious culture, however, principles may evolve without any recognition that alternative principles are even possible. The arguments accumulated in such cultures could become integrated in an aesthetically satisfying way, and yet all of them make the same basic mistakes.

Principles become explicit at the rational spiritual stage for the same reason that subjective animals acquire a general conception of the structure of space and manipulative animals acquire a general conception of geometrical structures. It is a consequence of the neural mechanism that gives subjects a faculty of imagination and how behavioral schemata evolve within it by reinforcement selection.

Arguments are constructed by linguistic behavioral schemata contained in the frontal neocortex, and they use covert behavior to act on the subject’s worldview in much the same way as locomotor schemata use covert behavior to act on the map of the mammalian territory and that manipulative schemata use covert behavior to act on object images within its local images. Covert behavior calls up sequences of images, but the evolution of kinds of covert locomotor or manipulative behavior establishes labels for calling up kinds of sequences of images. With the development of generalized behavioral schemata, particular events would be seen as instances of some kind.

In the same way, the evolution of kinds of covert linguistic behavior for arguments establishes labels for invoking certain kinds of reasons for drawing conclusions in certain kinds of situations. The difference is that in the linguistic case, the behavioral schemata can be generated, not only covertly, but also overtly as verbal behavior, and thus, the general conceptions can also be represented publicly as principles.

An implicit conception of efficient-cause connections would already have evolved with a primitive language of natural sentences. The covert nonverbal behavior of linguistic behavioral schemata also act on a worldview of states of affairs (using a mammalian map to refer to objects in space) to call up images of their effects and causes, and situations that could be handled in the same way would have led to the evolution behavioral schemata for constructing naturalistic images that established labels for the kinds of causes and effects involved in them. But without the use of psychological sentences, mere linguistic subjects were unable to represent states of affairs as causes, and the nature of the connection between causes and effects could be expressed only implicitly by their verbal behavior in certain social contexts.

Likewise, the evolution of linguistic schemata for using psychological sentences would give them a general understanding of rational causation, for neurological development would lead to labels for kinds of psychological images that have similar causes or effects.

With the evolution of psychological sentences, however, reflective subjects would also have an explicit concept of cause, for the ability to think about how they are using naturalistic or psychological images to represent the casual connections among states would enable them to represent causes as causes. Given their general understanding of causal connections, therefore, they could also represent principles about causation as principles about causation, either naturalistic or reflective. And since they could understand the causal roles of the psychological images being constructed by such talk, they could identify some propositions as premises or reasons for other propositions as conclusions, making the inferences they intend listeners to construct in their rational imaginations clear. Thus, rational subject could formulate general arguments about how to handle whole ranges of situations all at once and recognize that they are appealing to general principles.

The evolution of principles would make the arguments accumulated as culture more complex, because as we have seen, the arguments would come in groups and stand or fall together. That is, they could have a general theory about each fields of situations, and a single argument could affect a whole range of conclusions at once. Biological evolution has no parallel to the integration of arguments at the ecological level in cultural evolution.

The change of culture in the direction of maximum holistic power for arguments is, however, only a tendency in spiritual animals. It occurs only when arguments go through reproductive cycles, and spiritual animals differ in how completely and regularly linguistic interactions among the members embody that ontological cause.

The extent to which members look for differences in their world views and argue about them would probably be rather limited until spiritual animals evolved into civilizations. When whole classes of members were freed from urgent demands of controlling immediate conditions affecting their reproduction, there would be leisure to argue about issues that are not pressing, and when writing evolved, complex arguments could be preserved an passed on from one generation to the next. But even civilizations would not undergo much cultural evolution, unless their culture happened to value argument and independent judgment. Because of how behavioral schemata evolve by reinforcement selection in each brain, the natural tendency of reflective subjects born into spiritual animals is to believe what everyone else takes for granted and to pursue the goals that are generally valued. Considering the importance of mutual agreement in being able to coordinate the members and act as a spiritual animal, such disagreements might even be repressed, unless they could not be avoided for some reason. Indeed, such inhibitions may be so limiting that rational selection is little more than passing the language and social practices on to the next generation. And overcoming the herd instinct may require special genetic conditions as well as special cultural conditions. But when the right conditions did hold, and regular and sustained argument about the whole range of situations did take place, there would be an inevitable tendency of culture to evolve in the direction of natural perfection for arguments of their kind.

Far reaching cultural evolution is not as accidental as its dependency on such conditions makes it seem, because the spiritual animals in which this limited form of reproductive causation is contained are themselves evolving biologically at the social level. Spiritual animals are a form of life whose reproductive cycles add up in real space over time, and thus, they impose natural selection on themselves at the social level of biological organization. Since one of the conditions they must control is making correct decisions about war and peace, they are subject to a strong, group-level selection pressure, which would favor spiritual animals in which cultural evolved more quickly.

Considering the additional power that cultural evolution would afford them, it is clear that biological evolution would eventually favor spiritual animals that fostered the conditions for cultural evolution to occur. Or negatively, natural selection by warfare would work against spiritual animals whose cultures did not give their members as much opportunity to judge arguments by their coherence — or at least it would, if they were also unable to assimilate the discoveries that occurred in the cultures of other spiritual animals.

In the overall course of evolution, therefore, biological natural selection at the social level would eventually shapes the social, cultural and biological mechanisms sustaining the rational selection of arguments, so that the cultures of spiritual animals generally would tend to change in the direction of maximum holistic power for arguments of their kind, that is, would tend to discover the true, the good and the beautiful.