Evolution and the Sin in Eden
A New Christian Synthesis

Chapter 10: Biology and "Concupiscence". Motor Control of the Passions?

We ask next why our human nature is so composed that the mind does not have direct control over the emotions. The structural design of the brain suggests that this is not a result of original sin. As we saw, St. Augustine theorized that Adam and Eve "experienced a new motion of their flesh which had become disobedient to them" because of their sin (City of God 13:13), but it is a theory which is difficult to defend today.

Rather than looking for a change in the physical biology of humans due to original sin, we should locate the reason for our moral weakness in the dynamics of human cooperation with the grace of God. We believe that when humans disobey God and commit mortal sin, as Adam and Eve did, they deprive themselves thereby of the state of sanctifying grace. It happens only too easily that they then become easy victims of various other temptations to sin. In this situation man stands in utter need of rescue by God.

When the sinner converts, when he receives God's forgiveness and His grace, he becomes equipped once more to persevere in this condition of restored supernatural life, though he may have to contend with determination against self-acquired vice. Although he is thus healed personally, the social condition of the human race in whose midst he lives is now marked by original sin. Racial solidarity of obedience to God remains shattered. The fashion of sin in society is difficult to resist, much as fashions in dress and other social behavior draw us powerfully toward social conformity. Rebellion against God, or simple discounting of His sovereignty, remain regrettably fashionable in much of human society. In this chapter we explore, with the aid of biological data, why it is normal that tension between our reason and our natural drives persist even when we are in the state of grace. What Trent termed "concupiscence" is seen to be normal and healthy natural drives functioning as they ought. Because they are natural and attuned to earthly life, they continue to operate after Baptism like before, subject only to the "political" governance of the will and modification by the influence of grace. Their natural function oftentimes brings them into conflict with our supernatural calling to transform our lives on earth into a training session for entrance into heaven.

St. Thomas Aquinas (1225-1274), the next intellectual Olympus in the Church after St. Augustine, generally agreed with his great predecessor that original sin must have done something to cut off control by the mind over the emotions. Like Augustine, he felt bound to interpret Genesis quite literally as did the other great thinkers of their time. The Church had not yet given guidance that Genesis 1-11 is not interpreted correctly as the kind of chronological history which has become traditional since Greek and Roman times. The interpreters who had misunderstood the sense of Genesis concluded with misled logic that if Adam and Eve could stand before each other naked and not feel sexual tension, they must have had very direct control of mind over matter. God subsequently deprived man of this privilege because of original sin, so they concluded. And in punishment for original sin man has now to use effort and good sense to keep the unruly emotions corralled in some semblance of domestic peace.

St. Thomas, following the lead of the brilliant Greek philosopher Aristotle (384-422 BC), described our limited domination of the passions by the term "political control":

Hence the Philosopher (Aristotle) says (Polit. 1,2) that the reason governs the irascible and concupiscible not by a despotic supremacy which is that of a master over his slave, but by a politic and royal supremacy, whereby the free are governed, who are not wholly subject to command" (ST I-II,17,7).

Political control is a good description of what our minds can now do in relation to the emotions. Our reason can agree or disagree with the spontaneous movements of instincts and emotions, can assent or dissent, can wish them to quiet down, can seek to distance their functioning from their source of stimulation, cut the line of perception, can busy the brain with attention to other business while the neglected passions then run out of energy. But as politics go, so also our control of the passions has its ups and downs, partial successes and partial failures. Through firm determination on part of the will and by means of sagacious political maneuvers, we do manage to get along fairly well with our passions. We depend upon our perceptions constantly to maintain our awareness, for they are our allies, essential to support our faculty to make free decisions.

But motor control over the passions eludes our efforts. Whether we like it or not, whether we agree or disagree, our pride, our greed, the sex drive, anger, appetite for food and drink, envy of the neighbor, our laziness and tendency to escape duties, our unruly ambitions for undeserved or destructive fame -- all this "concupiscence" is equipment by which we live out our personal lives and by which society functions. Like ever changing weather, they occasion frustration as well as joy.

These very same drives which capacitate us for normal life can with equal aplomb threaten our own self interests, our love of God and neighbor, as well as the common good of society. None of these drives obeys commands to start or stop instantly as do the more pliant movements of hand and foot which are under motor control. When a king commands his daughter to marry and love a prince, she can do the marrying in a ceremony, but she may not be able to obey her father to generate emotions of love. Emotions are chronically allergic against control by dictator reason, like children who always learn to say NO before they learn the word YES. The emotions operate on automatisms which are not under immediate motor control of the will.

Even if we did have motor control over our passions -- even if we could, for example, stop envying the neighbor by command of the will -- would we always be willing to do that? The angels who were not encumbered by passions of a body were able to decide for good or evil, yet not all of them chose what is good. Which suggests that even if our reason and will would have motor control over sentiments of pride and ambition, that alone might not guarantee that we choose correctly. Genesis teaches that our still flawless Adam and Eve fell during their very first trial. In the final analysis, our decisions are made not by passions, but by our reasoning selves who are free, who have these passions as part of our life equipment.

The Emotions and the Triune Brain

We invoke the help of specialists to provide information about brain structures and the neural substratum which houses the emotions. Our brain is remotely comparable to a thousand telephone switchboards, each serving a gigantic megapolis, whirling with the activity of generating, receiving and transmitting messages. "Through its incredible ability to hook together thousands of reverberating circuits in a fraction of a second -- each representing a memory of an idea -- the brain is able to bring together into one grand circuit the data needed to think and make decisions" (Bruce Bliven, 52).

The three main sections of the brain are said to reflect a three stage evolution:

1) The basic ganglia or stembrain. It is sometimes called the "reptilian" section. This regulates the basic body functions.

2) The midbrain or limbic system. Called also the "mammalian" section, it is the seat of the emotions.

3) The neocortex or forebrain. It is said to be the newest part, the specifically human section. We use it to think and to exercise free choice. It is not set into the cogwheels of the emotions whirling in the midbrain, but acts as a benign though sometimes aloof boss of the limbic complex.

The stembrain controls basic life functions such as breathing, heart beat, endocrine output, general metabolism. It can continue to operate even when the forebrain computer is down.

The midbrain is the biological agency of our emotions (read concupiscence). Its circuits support our activities of love, joy, tenderness, hatred, sadness, envy, pride, ambition. The midbrain is said to have developed during early mammalian life. Mammals have more emotional capacity than do reptiles.

The neocortex or forebrain is distinctly human, a species specific later addition to the older mammalian and reptile brains. It capacitates humans for rational and linguistic operations. Geographic areas of this neocortex are mapped for their specific functions, such as abstraction and speech, for motor control of foot, body, hand, face, eye, and areas which process vision, hearing and other functions. Yet none of these neocortex areas operate as isolated performers. Whenever they operate they do so in vital connection with the entire brain.

As Philip Lieberman notes: "Although some brain mechanisms may be language specific, we cannot assume that all brain mechanisms involved in human language constitute an isolated organ." And although human language and thought probably are the "newest" attributes of Homo Sapiens, their brain bases are not restricted to only the phylogenetically newest parts of the brain. Though we undoubtedly have specialized neural organs, mechanisms that evolved to facilitate cognitive and linguistic activities, these in turn developed from simpler and earlier organs which had supported less complicated functions. And the more newly developed areas "usually continue to participate in the older, simpler patterns of behavior as well as in the newer, derived cognitive activity" (Uniquely Human, 1991, p. 15).

The thinking brain, mainly our neocortex, operates in biological conjunction with the emotive midbrain, as well as with the basic life ganglia of the stembrain. It cannot operate by itself, without the combined assistance of the midbrain as a working partner, and of the stembrain as the supplier of life energy. The entire brain family must be present and willing if the forebrain is to do any thinking and willing.

But the midbrain is different. It can operate without the neo-cortex. We can emote without thinking. However, the midbrain cannot operate without input from the stembrain. We cannot emote with the midbrain unless the basic ganglia keep us alive by operating the vital functions.

The stembrain can keep us alive by itself, even when the two higher brain compartments are asleep or out of action. We have, therefore, three brain compartments, the rational forebrain, the emotive midbrain, and the vital stembrain.

The Sex Drive, Gateway to All Emotions

Jerome Lejeune notes that the forebrain projection of the genital organs is at the upper extremity of the Rolando fissure in the interhemispheric surface, very close to the midbrain. It is therefore the one and only cortical representation to be in contact with the limbic locale of emotions; this is the crossroads of the drives needed for the preservation of life (hunger, thirst, aggression) and the drives needed for the preservation of the species (reproduction, protection of the young, love). It follows that we are so constituted that whatever concerns genital activity involves also moral activity, neurologically speaking. This points to the impossibility of mastering emotional behavior if we do not first master conscious and deliberate genital behavior (cf. Lejeune, "Is there a natural morality?" in Linacre Quarterly, 1989).

Professor Lejeune here makes the significant observation that voluntary sexual discipline is the gateway through which we must pass to take control of emotional life. The very important conclusion follows that one who governs his sexual appetite reasonably well is thereby in the key position to control all the emotions. He will likely also control fairly well greed, envy, anger, love, hatred, sadness. Boys achieve virtuous manhood, girls develop well--behaved womanhood first and foremost by disciplining themselves in proper sexual behavior on the way to adulthood.

The intense struggle to control the emerging sex drive which every boy and girl experiences during the process of growing to maturity is a moral necessity imposed by God and nature. Temptations are strong, keen, lasting, sometimes unexpected, utterly flattering to heart and mind. Years of struggle does not tame them. Yet by mastering them with firm and constant resolve - and by rising again and again after a fall - we acquire the bonus reward of tempering all our other natural drives in tandem with the sex drive. This indicates how very beneficial it is for adolescents to be educated in chastity and encouraged to practice it with unbending resolve. It also indicates how great is the evil of those who scandalize youth by imparting sex education in a manner which arouses passions and inculcates no values. Without disciplining the sex drive, youths fail to form strong moral characters, and society as whole deteriorates. The human community enjoys distinct advantages when its members act reliably and responsibly: when airline pilots practice sobriety and study to remain competent, when bankers are honest, when laborers do their job well. By stirring up unruly sex habits in youth, faulty sex educators tend to collapse individual and social reliability in the entire population of the next generation. We are all losers if a generation of juveniles is influenced against disciplined sexual mores. Youths who do not keep a tight rein on their sex drive lose much control over other areas of character development.

Adolescents who surrender their neo-cortical freedom by yielding to sexual abandon, thereby stunt growth toward emotional maturity. The body may grow into adulthood, while emotional childishness persists. The sex playboy may also be a thief because of greed, a drug addict because of low self-image, a cheater in games, a copycat in examinations, a liar who will not admit that it was he who "cut down the cherry tree." Even though the body grows big into adulthood, the character remains a cretin, a playboy in a grown body.

Lejeune draws this implication about behavior from the fact that neurologically the projection of the genital organs in the extremity of the Rolando fissure of the neocortex is situated as a gateway into the limbic system which is the theater of concupiscence, of the emotions. In other words, he who controls this gateway of genital activity gains the upper hand in dominating all the restive emotional drives and powers. He controls the strategic gateway between rational life and animal life.

Motor Control of Emotions?

Augustine spoke of an alleged ability by innocent Adam to call the emotions into action when reason and free will want them to go into operation. He postulated likewise that reason can stop their action on command. That concept translated into brain functions would indicate that the forebrain overrides the midbrain when it issues a command. But that is not the way our brain functions today.

Today the emotive midbrain operates antecedently to the forebrain. It capacitates the forebrain for action. The forebrain does not simply control midbrain and stembrain at will. Quite the opposite, unless the midbrain takes an initiative, the forebrain is paralyzed. Only after the midbrain capacitates the forebrain for action can this forebrain begin to influence the midbrain. Once capacitated, the forebrain can inhibit activities of the midbrain. It can tone down some activities directly to a certain extent. It can also divert attention away from its exciting object to thus shut down the midbrain's heated activities indirectly. The higher cortex, the seat of reason and will, is more effective in inhibiting the free flow of the emotional functions than in initiating them, explains Msgr. Timothy Gannon, following Paul Maclean:

The cortical centers are much more effective in inhibiting the free flow of these functions than in initiating them... It is as if the commands of reason are too harsh and too abstract to be translated directly into behavior (Gannon 28; 30).

The degree of autonomy exercised by the brainstem over the ongoing functions of life, such as heart beat and regulation of the blood sugar, makes direct control of its functions by the cortex impossible. The stembrain does all this without need of conscious direction by the forebrain. This allows the forebrain freedom to pursue intellectual activities without need of overseeing breathing and heartbeat and basic vital activities.

Between the life functions controlled by the stem, and the thinking functions seated in the cortex, is the midbrain area which processes emotions. It is to this area that our attention is drawn in our discourse about concupiscence. If today our neocortex cannot exercise complete motor control over the neurological activity of the limbic midbrain, nor of the brainstem, then how did Adam do so unless his brain was structured differently than ours is? That is, unless his forebrain could override the midbrain and stembrain.

If Adam had our kind of brain, but could draw directly on spiritual powers to activate or deactivate the limbic midbrain and the brainstem, he would be a "miracle man." He could at will simply by-pass normal biological processes by means of powers of the spirit. We might call it "mind-over-matter" or angelic powers.

The other alternative is that he would use not spiritual powers but biological operations to govern his emotions with instant motor control. His neocortex would then use neurological pathways to overrule the limbic system. If Adam could do that, then his brain structure would have been essentially different from our own. That would necessitate an entire restructuring of all other bodily functions. Even so, it wouldn't function. Such an Adam would be a piece of biological junk.

Gannon explains how the limbic midbrain mediates to make the neocortex aware. In subsequent response, it adapts the commands of the neocortex to the biological capacities of the body's organs. We might imagine that Adam's neocortex could take command of the midbrain to override its mediatory functions, in order to evoke obedient action from it. But that would require more than natural powers. Gannon writes:

And this is precisely how we experience emotions; as an awareness intervening between the clear dictates of reason and the appetites controlled by lower centers... To speak of sexual functions as if they could be turned on or off by a simple directive of reason ... is a grave error...The whole triune brain functions as a unit with the three levels completely integrated (Gannon, 30;31.).

The Augustinian concept would have the reason (neocortex) take the initiative of calling emotions into action, or shutting off their activities. But our brain functions exactly in the opposite sequence. It is the feelings housed in the midbrain which serve up to the reason housed in the neocortex an awareness of what is going on. This arranges the stage upon which the mind can then make choices. The intermediary limbic lobe is, in turn, closely connected with the stembrain below it, constantly initiating or mediating orders to the stem, and in turn receiving stimuli from it. As Gannon explains:

As the feelings and emotions arise in consciousness they bring with them an awareness of the self, the awareness of how we feel about the activity in question, and an incipient movement toward or away from it. This pattern of the manner in which the brain functions also goes a long way in helping us to accept the paradox ... that it is the feelings and emotions that make the brain work, rather than the other way around (Gannon, 30.).

Emotions cannot function in the brain alone but are in vital dependence upon the physical teamwork of the entire body. Thus the emotion of anger, agitating the nerves in the midbrain, stimulates the stem brain to send a message to the adrenal glands to produce and pour into the blood stream a series of hormonal stimuli which are targeted for the receptors in different organs of the body. Anger is not a mere "tempest in a teapot" of the brain, but involves myriads of supporting systems and operations in the body. To support the anger and to make it physically effective, the body then ups the tempo of the heart-beat, increases the concentration of sugar in the blood to fuel the muscle fibers, tenses the muscles, increases alertness of eyes and ears, flushes the face, perhaps erects hairs in their follicles and flashes lightning from the eyes.

To illustrate the magnitude of the operation -- comparable on a mini-scale with initiating and maintaining the logistics of the D-Day Invasion of the Normandy Coast -- we draw attention to only one of the many items involved, the sugar content in the blood. To do battle when angry, the blood sugar is consumed at a higher rate than when the body is at emotional rest. The level of sugar in the blood is critical to total bodily health. We pay a great price if the sugar level gets even slightly off balance: "Sugar is one of the body's energy producing substances and we must have just the right amount, no more and no less. We walk a biological tightrope between coma [insufficient sugar] and convulsion [excess of sugar], the possible results of relatively light changes in blood-sugar levels (John Edward Pfeiffer, M.D., "Introducing the Brain" p. 47). The brain keeps us alive by monitoring the systems continuously and keeping them in balance.

If Adam had been capable of giving direct orders to his body to be angry, or to stop anger instantly, he would likely have made impossible demands upon his biological system. Our system functions best when the commands of the neocortex are filtered through and seconded by the limbic midbrain, which in turn excites the reactions in the stembrain which then makes the body cooperate in accordance with the orders of the remote "commander in chief." As a result, the passions may appear to be "stubborn" or irrationally persistent. But we should recognize that there is a biological reason for this "irrational persistence." Complex and time-consuming biological processes necessarily result in a "fly-wheel" governing modification of the passions. A response cannot be instant, but only gradual; the flywheel goes into motion slowly at its own pace. Neither will the flywheel stop instantly when once in full motion.

The body must provide the biological basis for any and every action which is tinged with emotion. It supports anger with a modification of the organism which equips it for a battle, or for defeat in helpless frustration. The entire body needs to be adjusted to perform a sexual episode, to generate a spasm of envy, to knot the body in hate, to expand the emotion of love. If Adam would suddenly stop the emotion during mid-performance, there would be no combustion of the abnormal amount of blood sugar, the heightened tension of the muscles would remain unrelaxed, the body would go into convulsions, perhaps into shock and a life-threatening situation. He would poison his systems with uncombusted deposits. Contrary to a popular misunderstanding that the passions are in disorder as a result of original sin, we ought to recognize the limitations of our physiological nature. Our biological system is marvelously constructed to serve our emotions, and the emotions are faithful supporters of thinking brain. Adam's sin has not, I believe, disturbed our physiological condition.

If we suppose that Adam had motor control over the emotions and drives and instincts -- over concupiscence -- either his brain and body functioned differently than ours, or he had spiritual powers by which he could override the biological circuits, akin to what we will have after the resurrection. Neither of these explanations satisfies us. If his brain and body functioned differently than ours does, then he was not of our species, and we are not his descendants. If he had spiritual powers like a resurrected body, then he belonged to the angel world, not to our world of mortals. An angel is not our ancestor.

Children Model Their Lives on Parents

Augustine confessed that he had found it exceedingly difficult to break out of his habit of sin. Once he had this habit it became a kind of second nature to him. Its demands were impetuous, taking over a kind of secondary control of his mind and body. His father had not educated him to control his sexual appetite. In fact, his father had noted with pride signs of his sexual prowess, whereas his mother ineffectively warned him against fornication and especially adultery. Had both father and mother educated him effectively by word and example to be chaste, and had his neighbors, his village, his school, his parish, his entire known environment expected him to be chaste, then perhaps he would have chosen to live chastely from the beginning. Solidarity in virtue practiced all around him may have motivated him to be always chaste. That is also the logic of a paradise without sin: if the entire community would practice virtue in complete solidarity, its exercise would become easier for each individual.

If all parents in the world would control concupiscence and educate their children by word and example to do likewise; and if all members of social structures and all administrators of government would converge in solidarity to make the ten commandments dominate in private and public life; and if the entire human family would then adore the Lord their God faithfully, it would be easier for all to say with Paul: "In all things we conquer overwhelmingly through him who loved us" (Rom 8:37). But original sin has shattered this solidarity of the human race in the universal practice of virtue.

When parents educate their children well, especially now when original sin affects social life, they make it easier for the children to practice virtue thereafter. Learning virtue when young is like learning a language during childhood. Whatever language there be, the child is equal to it. It can learn any of the thousands of languages in the world, be it English, Japanese, Chinese, Swahili, or any other listed on the plaque of the Tower of Babel. And it soon speaks in the local dialect.

In much the same way we see children acting like their parents, and take on the behavioral pattern of the extended family and of the surrounding community. Their brains are initially habit-neutral, so to speak, plastic and elastic enough to be molded into habits of good or habits of evil. Children refuse, however, to have virtue imprinted upon them. Outsiders can provide models and motivation, but each child must do its own imprinting.

Behavior Modifies Neural Automatisms

Dr. med. Josef Roetzer quotes the famous dictum that "the mind molds the brain" (see Roetzer, "Humanae Vitae," p. 769). Brain researcher Wilder Penfeld had coined the phrase which calls attention to the fact that the brain is subject to physical alteration by the teaching that parents give to their children, and by the personal efforts which the child and the adult make. For the molding of the brain to facilitate the practice of virtue is a lifetime task, though it is enormously easier to start well, than to make adjustments and corrections later in life.

Nobel prize winner John C. Eccles spoke of a self conscious mind which acts as a liaison brain to then mold the organ of the brain which we possess (cf. Roetzer, 769). We might say that this "liaison brain" is our conscious effort, is the work of a midwife, to facilitate the birth of habits. In other words, the ideal which we set before the brain can be the blue print which guides and stimulates the brain to shape itself accordingly.

To learn the ten commandments from our parents, then, is an advantage which expedites and simplifies the proper formation of the brain of the child. And the child who has initially learned correct conduct from the parents, has the task of on-going formation which it must continue on its own.

Man's appropriate organ for exercising choice is his unique brain. The brain can be regarded as the organ of man's personality. What he has experienced in his life, the considerations he has had to think over, the attitudes he has acquired - all these things accumulate in his brain. The brain must be molded and shaped in the right way if man is to use it as an organ of free will. We have already spoken of the moldable capacity, the plasticity, of the brain. We must consider the formational stages of the brain.

Take, for example, the mother-child relationship in the first years of a child's life. The child must experience mother's love in order to acquire the ability for social communication without fear or hate. You all know about the difficulties arising from disturbed people who perform acts of violence against society because - of course, that is in many cases only a part of the pertinent cause - they have not experienced the love of a mother in the formational period of the brain concerned with this attitude. The older a patient grows, the more difficult becomes therapy for any disturbed behavior, because the brain is successively losing its plasticity (Roetzer, 768-769).

The sin which Adam and Eve committed de-flowered the virginal seal of an inerrant development of virtue within themselves first of all. The molding of their brains to facilitate the practice of virtue was no longer guaranteed by lives of constant obedience to God's commandments. They, in turn, passed on their own deficiency to their offspring, not by the genetic route but by a distortion in the pattern of their education. In turn the community became adversely affected by ripple effects of disturbances, all of which became a part of the "sin of the world" into which we are born.

On the other hand, because we are free and God gives all the help we need, each of us can live virtuously and peacefully. Even the entire human family can rise and shine to create a global solidarity in virtue provided everybody cooperates. God, however, does not imprint such a solidarity upon our race. He offers us the joy of endeavoring to achieve it ourselves.


Parents should normally and routinely rebuild the wall around the Garden of Eden for their children. Within the Garden of the Home parents can shelter the children from the sinful world outside, and form them in virtue. Young children eagerly copy the behavioral model of their parents. Their good behavior in turn helps to mold the brain to facilitate virtue during adulthood.

The alleged mind-over-the-passions control of Adam and Eve which Augustine once taught is probably a biological impossibility. We have no proof that Adam and Eve controlled their emotional life in a manner other than we do. It is only after the resurrection that "the soul will...communicate to the body...impassibility and glory" (Thomas, ST I,97,3).

Until that time comes we can live in victorious tension with concupiscence, in a politically enforced peace, a peace which Christ gives us.

Next Page: Chapter 11: How the Sin is Transmitted
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