It appears we human beings are of two minds. One is good at building those sophisticated intellectual structures, models of the objective world that have given our kind great power to alter our environment. The other is the seat and source of our emotional experiences.

These days it is popular to refer to these as the left brain and right brain minds, however such a physical mapping is almost certainly a gross oversimplification. Let us not presume to know more than we do about neuroanatomy and name them from a functional standpoint and refer to them as the sapient and the sentient minds.

We can use evolutionary considerations to formulate a theory about the how these two distinct aspects of the human mind function and interact. Why evolutionary considerations? What else? The problem is one of reverse engineering a design but the mind was not designed it was created as the result of a natural process; evolution.

In the 1960’s Paul D. MacLean formulated his model of the Triune Brain, a theory of brain evolution and human behavior that was subsequently popularized in Carl Sagan’s book, “The Dragons of Eden.”

The Triune brain consists of three parts, the reptilian complex, the limbic system and the neocortex. These structures are understood as being sequentially added to the forebrain in the course of evolution and of being the seat of progressively more sophisticated instinctual behaviors.

The “reptilian brain” or R-complex, so called because it was believed that the forebrains of retiles and birds were dominated by these structures is, according to the model, responsible for aggression, dominance, territorially and ritual displays.

The “limbic system” or paleomammalian complex, thought to arise early in mammalian evolution, controls motivation and emotion involved in feeding, reproductive behavior and parental behavior.

The neocortex a structure that is unique to mammals and regarded as the most recent step in evolution provides abstract thought, planning and language.

Since the theory was formulated further research in neuroanatomy has cast some doubt on the validity of MacLean’s particular mapping of functions to brain structures.[1] Yet the basic idea, that our psychology evolved along with our physical brain and retains behavior mechanisms from earlier evolutionary stages remains compelling.

It explains why other mammals appear to experience similar emotions to our own. If humans and cats, for example, share evolved psychological adaptations (wherever these reside in the physical brain structure) then is it not unreasonable to suppose that when your pet cat appears to exhibit jealousy when a new puppy is introduced to the household, it probably is experiencing something very much like that human emotion.

Equally intriguing about the idea that we possess a psychology resulting from three distinct stages in evolution is that nearly every model of the mind throughout history from Plato to Freud also feature three distinct components, with each part understood to be responsible for progressively more sophisticated behavior.

So we suppose that the sentient mind evolved second, after the hind brain, possibly appearing along with the more highly developed limbic brain that humans share with many other species of mammal, while the sapient mind is quite new on the evolutionary time scale and arrived with the more highly developed cerebral cortex that separates humans from all other species.

The sapient mind evolved because it gave our ancestors the means to exert control over their environment; the ultimate survival mechanism. Before that the actions of our evolutionary ancestors were governed directly by a rich matrix of emotional responses that allowed them to respond to events in their environment in a way that was generally conducive to the species survival. More specifically, it enabled the formation of complex social groups.

This sentient mind was and is structured, sophisticated and nuanced; an emotional instrument capable of producing experiences of unlimited subtlety. Its experiences are distinct from the more reflexive impulses such as flight-fight response and sexual lust which are probably associated with an evolutionally more privative behavior mechanism which we have in common with a wide variety of species including many which exhibit little or no social instincts.

The passions that arise from the hind brain (if that’s where they reside) cannot be ignored, of course. They are like the base notes of the emotional harmony (or sometimes cacophony) of the human emotional experience. It is important to understand though, that they are fundamentally different from the emotions that are produced in the sentient mind. They belong to an even older, simpler control mechanism.

Evolution never goes back and cleans up after itself. The stimulus-response control mechanism of the earlier evolutionary stage was subsumed not replaced by the more sophisticated system of desires and aversions that characterizes sentient mammals. Similarly we can suppose that in humans the sentient mind exists intact and unaltered by the evolution of the intellectual functions of the sapient mind.

If these evolutionary speculations are valid, human behavior must be understood as resulting from the interaction of these three fundamental aspects of our psychology.

We need to look back down our evolutionary timeline to a point before our intellect and its powers of abstract thought and language became significant. A point when we lived entirely by our instincts exactly as other mammals, horses, for example, still do.

We know that our ancestors of this epoch lived in complex social groups, hunted in packs or gathered in herds, guided by a rich matrix of emotional responses. Without language or abstract thought, individuals recognized and responded appropriately to family and group members, doubtless knew when to follow the alpha leader and when to challenge and so forth.

These instinctive emotional responses and the cognitive abilities, such as perception and recognition that support them comprise a sophisticated control system that results in the individual performing actions in response to incoming perceptions that generally result in a favorable outcome for the group.

Complex social behavior requires more than the stimulus-response impulses of the hind-brain. How did our ancestors recognize and conform appropriately to social roles without the sophisticated abstracts concepts of the intellect?

The answer is that the sentient mind must have evolved to incorporate a rich set of built-in abstractions, social forms that are relevant to social behavior. These would be on the order of Father, Mother, Child, Friend, Foe and so forth. Special perceptual abilities such as face recognition and sensitivity to body language would have evolved concurrently to support mapping sensory perceptions into the appropriate built-in form.

These built-in forms are what psychologists since Jung have called Archetypes. This realization gives us the key to compare and contrast the sapient with the sentient mind.

The sapient mind understands perceived objects to be instances of a general class of things represented by an abstract concept. These general classes are arranged hierarchically such that more specific classes inherit attributes from more general ones. This facilitates learning since a person can easily comprehend a complex object such as a steamboat if their abstract model of the world already contains concepts for boat, motive power, and steam engine.

The sapient mind constructs a general world model out of these abstract concepts and requires it to be consistent with the rules of logic and causality while being contained in chronological time and three dimensional spaces. Whether this way of understanding the world is the best or most accurate way to construct a world model is beside the point. The sapient mind works this way and no other.

What we can say is that this particular ability to build conceptual models is that it gives us power over nature. Theories concerning the underlying structures and causes of the things we perceive allow us to make successful predictions of future events. Thus we are able to create powerful technologies and gain mastery over nature.

That the sapient mind works well in the context of nature is not surprising since it came into being as the result of the natural process of evolution. But as a product of nature adapted to understand nature it has not been able to produce consistent, clear, predictive models of anything that lies outside of nature (if, in truth, anything does exist outside of nature.) One person’s metaphysics is as good as the next in that none are susceptible to objective proof or disproof, as are concepts of our natural science.

Why do we entertain that metaphysics is a valid avenue of inquiry at all? Why has concern with things considered to be supernatural persisted? The answer may lie in the experiences of the sentient mind.

The sentient mind appears to map perceptions into its built-in archetypes. These forms, unlike the intellect’s abstract ideas, have emotional experience attached to them. Everything that the sentient mind perceives evokes an emotional experience. Causality, time and space do not seem important to the sentient mind which lives only in the moment.

Direct evidence of how our sentient dominated ancestors may have experienced their lives may be provided by modern humans who have experienced temporary loss of some of their sapient mind functions and lived to tell about it.

One of the most notable and creditable of these is Dr. Jill Bolte Taylor, a neuroanatomist who experienced a severe hemorrhage in the left hemisphere of her brain. During the event she could not walk, talk, read, write, or remember her past life.  It took eight years for her to recover fully but eventually she was able to speak eloquently about her experience.

She described her experience of the event as one of euphoria, of awareness of cosmic forces, of a feeling of oneness with the universe. She felt that she was disconnected from her ego, in fact she spoke of looking down at her shoulder where she was leaning against the door frame and not being able to sense where her arm ended and the door frame began.

What is striking about how she speaks of the experience is that it is not only very similar to the described experiences of other people who have suffered loss of intellectual functions (through injury or self induced via mind-altering drugs) but also of how people throughout history have described what they call spiritual or transcendental experiences.

That is to say how they describe what the experiences feel like, how they understand what they experienced varies according to people’s intellectual belief systems.

The conclusion to be drawn is that the sentient mind is the source of spiritual experience and that our pre-sapient ancestors may well have experienced life to be egoless, euphoric and transcendent. Modern humans too are still capable of these experiences but only if we can somehow avoid the masking effect of our intellect.

What are these cosmic forces that people speak of perceiving, could they be the raw archetypes that evolved to channel our most fundamental evolved motivations to their proper objects in the outer world presented to us through our senses? How did they come to be obscured by the advert of the intellect?

Why did we evolve sapience in the first place? We tend to think of our conscious mind as the part of us that tells us what is good and bad for us and what we should do and not do. But does it really work that way? In fact we still do and seek what our emotions tell us to, the intellect with its sophisticated knowledge of the world, just makes us much better at doing them and finding them. The sentient mind is still the control mechanism.

It appears that the intellect is in charge because the intellect alters our understanding of what our senses are presenting to us. Prior to the development of the intellect when we perceived a ripe apple our sentient mind responded with desire. Now the perception of the apple is also processed by the intellect and maps into our model. We know that some apples taste good and others bad, which is this? The sapient mind may know that this particular apple is in fact poison and if eaten will cause death.

The sentient mind is presented with both the direct perception of the apple and experiences desire for it but at the same time it perceives the image of eminent death constructed by the intellect. The fear of death in this case overcomes the desire for the apple. We perceive we made a wise decision not to eat the apple when in fact we are just following the sentient mind’s dictates.

Human Beings evolved in nature to survive in the natural environment and as long as we did so our sentient minds and sapient minds probably worked pretty seamlessly. The sentient mind said I want something to eat, or shelter, or a mate and the sapient mind figured out how to get it. What we wanted was the same things as we always wanted reaching back into our most ancient evolutionary history.

We were intelligent and clever but we were ignorant, we lived by our senses and in accordance with the inner emotional voices of our sentient minds, we needed to be exquisitely sensitive to both to survive and thrive. We experienced our environment filtered through the sentient mind’s archetypal forms and their integral emotional experiences; we lived in a magical, spiritual landscape.

The sapient mind perceiving these experiences arising from the sentient mind naturally wrapped them in abstract concepts and integrated them into the general world model. Since the most powerful archetypes evolved to support social behavior, the archetypal Father or Mother for example, these concepts naturally tended towards personalization. Thus the gods were born.

The gods are creations of the intellect, abstract ideas formulated to integrate the experiences coming from the sentient mind with the world as understood by the intellect. While humans lived in nature their intellectual world model was rudimentary and in the absence of any empirical explanations it was a matter of course to attribute external forces of nature to the same archetypal presences already encompassed by their sentient minds.

It is important to understand, however that the gods were invented not as explanations of natural phenomena, which is pretty much the current view, but as ideas that brought into focus and made sense of emotional experience.

Our senses and our sentience evolved together before development of the intellect. Our emotional experiences, motivating us towards or away from objects in the perceived environment were intense and immediate. The intellect comes later and with it the ego which defines and separates us as individuals from the external world. It is not surprising that it has a difficult time distinguishing the sensation of an external object from the internal (but outside of the ego) emotional response to it. Thus religious teachers from time immemorial have had to remind us again and again, “God is within.”