From the time of Charles Darwin (1809-1882), there has been a noticeable amount of scientists who have argued that ethics can be completely explained in terms of evolutionary ideas alone.  As E.O. Wilson urges, “scientists and humanists should consider the possibility that the time has come for ethics to be removed  . . . from the hands of the philosophers and biologicized.”[1]  According to them, evolution demands that we should overthrow the currently prevailing Judeo-Christian paradigm of ethics. 

In contrast to this view, I will argue that these anti-Christian sentiments have nothing to do with evolution, but with an atheistic interpretation of the theory.  It is not within the province of scientific discourse to prescribe moral actions. Conversely, I will show that natural law morality is complementary with biological evolution and must be preferred over naturalistic interpretations of the theory.  I will then turn to a practical case to show that evolutionary ethics does not necessitate the overthrow of Judeo-Christian ethics, but reinforces the pro-life view in the surrounding abortion debate.  

Evolutionary Ethics as Inherently Atheistic?

According to Darwin, random mutations within the genetic codes of an organism will result in either beneficial mutations or unfavorable ones.  Mutations that are favorable to an organism’s life—a process known as "natural selection"—are subsequently passed on to the organism’s offspring, making it easier for them to survive.  These mutations accumulate over time, eventually culminating in a completely different set of organisms that are substantially different in nature from the original set of parents.[2]  As of today, evolution is one of the most well established theories in all of the biological sciences.  As Richard Dawkins, famously known as “Darwin’s Rottweiler”  puts it: “it is absolutely safe to say that if you meet somebody who claims not to believe in evolution, that person is ignorant, stupid, or insane (or wicked, but I’d rather not consider that).”[3]

Since the time of Darwin, some have concluded that evolution is intrinsically atheistic.  In Dawkins’ words: "Although atheism might have been logically tenable before Darwin, Darwin made it possible to be an intellectually fulfilled atheist."[4]  Controversial statements like these are well known in contemporary American culture.  It is not in dispute that many Christians have overreacted to the scientific validity of evolution in light of the theory’s atheistic endorsements.  Nevertheless, there has always been a significant amount of theologians, philosophers, and scientists who have argued that evolution has no bearing on the question of God’s existence.[5]  There are many atheists would agree with this contention.[6]  Of those Christians who accept the validity of the theory of evolution, relatively few of them have seriously taken the time to incorporate it within their ethical theories.[7]  Perhaps one of the reasons why Christians have not utilized the theory is due to the outspoken claims made by the atheists. 

“We now know,” says Michael Ruse, “that despite an evolutionary process, centring on a struggle for existence, organisms are not necessarily perpetually at conflict with weapons of attack and defence.  In particular, co-operation can be a good biological strategy.”[8]  Although it is rationally conceivable within an evolutionary schema that “might makes right” and that nature is “red in tooth and claw,” human nature has not predisposed us to make utterly selfish actions.  Ruse presses the issue: “I emphasize, in connection with this last point, that the claim is not that humans are hypocritically consciously scheming to get as much out of each other as they possibly can whilst perhaps pretending to be nice, but rather that humans do have a genuinely moral sense and awareness of right and wrong.  It is this which motivates them.”[9] 

Ruse explains the reason why we have this moral sense: “The simple fact of the matter is that, although winning outright in the struggle for existence is the best of all possible results, such success is often not possible—especially given that every other organism is likewise trying to win.  Consequently, one is frequently much better off if one decides to accept a cake shared rather than gambling on the possibility of a whole cake but one which might be lost entirely.”[10]  One cannot escape the disposition to think that morality is objective and that we are obliged to follow what are commonly thought of as moral norms.  “It is important, therefore, that biology should not simply put moral beliefs in place but should also put in place a way of keeping them up.  It must make us believe in them.”[11]  In light of these important truths, Ruse has argued that the primary tenet of the Judeo-Christian ethics are illusory: 

“The position of the modern evolutionist . . . is that humans have an awareness of morality . . . because such an awareness is of biological worth. Morality is a biological adaptation no less than are hands and feet and teeth . . . . Considered as a rationally justifiable set of claims about an objective something, ethics is illusory. I appreciate that when somebody says 'Love they neighbor as thyself,' they think they are referring above and beyond themselves . . . . Nevertheless, . . . such reference is truly without foundation. Morality is just an aid to survival and reproduction, . . . and any deeper meaning is illusory . . . .”[12]

Another example is the bioethicist Peter Singer.  He has used evolution to emphasize the strict continuity between animals and humanity.  In so doing, he has argued that humans do not deserve different treatment from animals.  Since humans are the product of blind chance instead of divine decree, there is no good reason to invoke the Christian system of morality that once reigned supreme.  “Quality of life” principles are to be endorsed over “sanctity of life” principles.  Abortion, euthanasia, and infanticide are not only permissible, but in some cases should be endorsed.[13]  In certain cases, animals have more value than human fetuses.  Thus, Singer: “Now it must be admitted that these arguments [in favor of abortion or infanticide] apply to the newborn animals whose rationality, self-consciousness, awareness, capacity to feel, and so on, exceed that of a human being a week, a month, or even a year old.  If the fetus does not have the same claim to life as a person, it appears that the newborn baby is of less value than the life of a pig, a dog, or a chimpanzee.”[14]    

Stephen Pinker maintains that the logic of evolution enables mothers to kill their newborn children, even after they are out of the womb.[15]  He wrote a well known article in the New York Times in response to some disturbing reports about a few teenage girls who killed their newborns by dumping them in the trash.  Reassuring the American public from the lecture halls of Harvard University, Pinker says that “if a “newborn is sickly or if its survival is not promising,” we should “cut their losses and favor the healthiest in the litter or try again later on.”  “The problem of Homo Sapiens,” says Pinker, “may not be that we have too little morality.”  Rather, “The problem may be that we have too much.”[16] 

In summary, all human behavior can be described and justified by referring to the way in which our genes have developed.  According to these atheists, the only thing humans should do is cooperate with their genes.  Since there is no teleology in the atheist’s evolutionary account, the chance processes of natural selection haphazardly dictate which behaviors and traits will prevail.  Humans must adapt themselves to the changing conditions of their environment in order to survive.  Through the blind process of natural selection (a process that is dysteleological), nature chooses which patterns of behavior are conducive for the human species to exist.  These patterns are known as moral behavior.  No divine law is necessary for humans to adjudicate right and wrong.  To include a supernatural basis for the moral law would make things complex.  Simpler explanations will do just fine.  Evolution, and, by extension, evolutionary ethics, is therefore atheistic.

Riposte to Atheistic Evolutionary Ethicists

I believe that there are many problems with an atheistic interpretation of evolution, as applied to ethics.  The first objection is that evolution can only describe human conduct, not prescribe morality.[17]  Certainly, the evolutionist cannot assess the most important moral question of them all: why be moral in the future?  One cannot move from the way things have been to determine what persons should do tomorrow.  What the atheistic evolutionist forgets is that in order to make a genuine ethical pronouncement, they must go beyond the scientific and enter the realm of philosophy. 

Second, it is well known that evolution cannot account for the highest forms of altruism.  On a Darwinian account, all organisms will act in accordance with their strongest passions.  But clearly we do not see this happening in society (martyrdom and celibacy would count as two perfect examples where high altruism prevails over merely biological considerations).  Although Darwinian analysis confines itself to lower forms of altruism, it cannot explain the highest forms of altruism.  Higher forms of altruism may be defined as those moral behaviors that do not bestow any genetic value at all.  Atheist Richard Dawkins, for instance, says he cannot explain “pure disinterested altruism” on an evolutionary account.[18]  Given these two reasons, why have the atheistic evolutionists continued to prescribe morality?    

Aside from the first two objections, which are noteworthy in and of themselves, the primary reason why these thinkers insist on believing that evolution can account for morality is that they think science is the only way to discover ethical truth (or, in some cases, the best way to know truth).  But in either case we are dealing with a form of scientism.  Scientism says “that the analytical and reductionist techniques of the . . . sciences provide the whole truth about every aspect of the real world, in a value free and completely objective, impersonal way.”[19]  Stated as such, science is different from scientism; the scientific is different from the scientistic.  Whereas science is concerned with the natural world, scientism circumscribes all valid knowledge to the scientific, assuming that the natural world is the only realm worth studying (obviously this would include morality).  But there are many problems with scientism. 

First, scientism is self-defeating.  Scientism is not scientific, but is a philosophical position about science (that is, the claim that scientific claims can be considered true and/or rational is a philosophical statement, not a scientific one).  Hence, the biggest and most immediate problem with scientism is that science is incapable of showing that scientism is true.  The scientistic thinker must borrow from non-scientific rationality to make the claims that he or she does.                      

Second, scientism does not allow for the task of stating and defending the necessary preconditions of scientific investigation.[20]  This would lead proponents of scientism to conclude that scientific truths are rationally superior to the presuppositions that undergird and justify those conclusions.  But that is, of course, absurd.  For example, scientists proceed on the assumption that they must be honest when gathering and collecting data.  But this cannot be justified scientifically.  Hence, there are many things that are true and extra-scientific, which scientism does not allow for (e.g., that torturing babies is wrong).  Similarly, scientism as a philosophy cannot account for ethical prescriptions.[21]  Just because something can be studied scientifically does not mean that it should be studied scientifically.  For instance, should science be used to research of weapons of mass destruction and/or how to clone human beings?  Scientists cannot answer this question, let alone proponents of scientism.  Only those with moral vision can answer this question.  The issue is not whether science can study how powerfully destructive weapons of mass destruction are, but whether or not this research ought to be done.  “When confronted with the moral law or with the moral significance of human life in situations of tragedy or of supreme goodness or radical evil,” Hebblethwaite says, proponents of scientism are “. . . unable to subscribe to a naturalistic philosophy of value as no more than intersubjective preference.”[22] 

Similarly, on a scientistic premise, there is no need to trust the rational faculties of persons, or even rationality itself (including the rationality involved in ethics). [23]  As theologian Keith Ward poignantly remarks: “They inevitably appeal to reason and truth, and to our ability to apprehend such things and adjust our beliefs accordingly.  Thus they transcend their own theories, for the adjustment of belief as a result of conscious apprehension and rational reflection is something that cannot be explained in terms of purely causal mechanisms or general laws, which can only deal with repetitive regularities and measurable, publicly observable data.”[24]    

Further, in hailing the “truth” of scientism, Dawkins, Ruse, Singer and others maintain that others ought to accept scientism, which implicitly recognizes that others can accept it.  Therefore, they assume that people have free will, which is the basis upon which others can accept their views.  Consequently, scientistic academicians do not, and indeed can not, believe in free will (because the materialistic worldview that undergirds their methodology does not allow for the existence of unobservable entities). [25]  Hence, it does not make sense for them to promote scientism because it takes human free will in order to accept scientism.  So if scientism is true, then it is false, and if scientism is false, then it is false as well!  According to Brian Hebblethwaite: “The implausibility of scientific reductionism at this point is particularly striking.  This goes for Hume’s give-away reference to ‘this little agitation of the brain which we call thought.’. . . . The very processes of rational argument and scientific research themselves presuppose our freedom.”[26]                      

Those who build their ethical approaches on a scientistic premise will eventually lose the right to decide what is moral.  The materialism undergirding their scientism logically allows for any moral action without justification: all must be reduced to the status of an object, and all must be explained in terms of general laws and causal mechanisms alone (notice that freedom and accountability are out of the picture in their views).[27]  No wonder that Ruse, Pinker, and Singer make the frightening claims that they do about persons.  In a scientistic universe, humans are merely “. . . objects for scientific manipulation; and the world they will come to inhabit, if it continues to exist at all, will be a world beyond morality, dignity, and freedom. . .”  Hence, it is “. . . a world of the manipulation of truth, of morality and of ideology, in the name of whatever powers come to replace the God whom science has killed.”[28]  In the name of making the world a more human place, advocates of scientism must uphold reductive views of the human person.                                

Fourth, scientific investigation depends upon faith in order to make the claims that it does, which makes scientism a self-stultifying approach to knowledge[29]  As of right now, advocates of scientism have been unable to solve all of the problems in the universe (by definition, scientism says that science will be able to “figure it all out”).  Not only does it seem impossible to solve all the problems in our world (according to any methodology), but scientistic philosophers must have some sort of faith to assert that science will be able to solve every relevant problem, including problems involving morality.  “Science,” says Ted Peters, “every bit as much as theology, rests upon faith.  Science must appeal to some foundational assumptions regarding the nature of reality and our apprehension of it, assumptions which themselves cannot be proved within the scope of scientific reasoning.  In its own disguised fashion, science is religious, mythical.”[30]    

Fifth, it is impossible to get around the human bias involved in science, and therefore it is nearly impossible to obtain the univocal, objective certainty that scientism strives to obtain.[31]  Scientific theories are provisional in nature; and they cannot exhaust the truth.  As J. M. Templeton argues, “Terms like significant period, some reason, and something like are the essential elements of a valid approach to scientific truth in the new scientific era.”  Templeton goes on to note: “This cautious approach, now accepted by a majority of working scientists, ought to instill in all of us a greater openness to the more philosophical and theological questions of meaning and purpose in our universe.  There simply are no exclusive pathways to truth!”[32]     

In summary, the idea that evolution can account for morality suffers from three major defects.  First, evolution can only describe conduct, not prescribe moral action.[33]  The scientific evolutionist cannot explain why we should be moral (because morality presupposes the validity of final causes; and science, it must be noted, is only concerned with the notion of efficient causes).  One simply cannot derive an “ought” from an “is.”[34]  There is a difference between mores and morals.  Genetic predispositions do not equate with moral predeterminations.  Peter Woodcock states, “It seems, then, that all we need at the biological level is ensure that people will act as if morality were objective is that there be a genetic disposition to believe privately what we offer as the public reasons for our actions.  In effect, that is a disposition to socialization.”  Notice that biological dispositions do not necessitate that people should do something, only that they are inclined to act in certain ways.  On a strictly atheistic interpretation of evolution, one cannot rationally justify any one moral action over and against another.  Woodcock pulls no punches: “Does this mean, then, that the worst tendencies of human nature will run rampant?  It certainly means that the egoist and the malevolent individual are no more irrational per se than are moral or altruistic individuals, that they must undermine their most fundamental goals in a way not true of the moral person.”[35]  The second major objection is that Darwinism cannot account for the highest forms of moral altruism.  The Christian notion of “Love your enemies,” which has been played out in countless forms across the ages, cannot be explained on a Darwinian account.  Simple altruistic acts, such as sacrificing one’s seat for an old lady on a bus, does not make sense on an evolutionary account alone.  The third reason is that it rests on a scientistic premise.  There are at least four or five defects with this methodology. 

Evolutionary Ethics and Natural Law Ethics

Since Darwinism cannot account for morality on its own terms, we must turn to philosophical considerations.  William Lane Craig explains one of the ways in which evolution is thought to be compatible with Judeo-Christian forms of natural law thinking:  “The reasoning of Ruse is at worst a text-book example of the genetic fallacy and at best only proves that our subjective perception of objective moral values has evolved.  But if moral values are gradually discovered, not invented, then such a gradual and fallible apprehension of the moral realm no more undermines the objective reality of that realm than our gradual, fallible perception of the physical world undermines the objectivity of that realm (emphasis mine).”[36]  At the very most, then, evolution can only show that we have evolved to the point so that we can know the existence of moral norms.  The question of how we know moral values has nothing to do with the existence of these norms.  These principles exist in a way that is independent of our conscientious recognition of them. 

Now if St. Thomas Aquinas were alive today, he would probably agree with the evolutionary depiction created by Ruse, Dawkins, etc..  Notice that in Ruse’s depiction of evolutionary ethics that he presupposes the same behavior for all human beings—a point the natural lawyer would gladly welcome.  Indeed, not only does Ruse presuppose a universal human nature, but he implicitly contends that these behaviors are shared by all normally functioning human beings—the desire to reproduce, pass on our genes, and safely raise children.  Even though we may expect slight variations across cultures, humans share the same concerns everywhere they live.[37]  In a crucial passage in the Summa Theologiae, Aquinas stresses that:

“The order of the precepts of the natural moral law is according to the order of natural inclinations.  For there is in humans, first, an inclination to the good in accordance with the nature which they share in common with all substances, inasmuch as every substance seeks the preservation of its own being . . . and by reason of this inclination, whatever is a means of preserving human life, and of warding off its obstacles, belongs to the natural law.  Second, there is in humans an inclination to things that pertains to them . . . according to that nature which they share in common with other animals; an in virtue of this inclination, those things are said to belong to the natural law which nature has taught all animals, such as sexual intercourse, the education of the offspring, and so forth.  Third, there is in humans an inclination to the good according to the nature of their reason, which is proper to humans.  Thus, humans have a natural inclination to know the truth about God, and to live in society; and in this respect, whatever pertains to this inclination belongs to the natural law: e.g., to shun ignorance, to avoid offending those among whom one has to live, and so on.”[38]            

Thus, according to Aquinas, there is an organic and biological basis for our inclinations toward morality.  Although Aquinas was ignorant of scientific evolution, the scientific evolutionist’s contention that our genes are responsible for guiding our moral activity smoothly parallels Aquinas’s emphasis on the vegetative powers of the human soul.  The vegetative powers of the soul, per Aquinas, are concerned with preserving organisms in being.  The functioning of the immunity system serves as a perfect example of the vegetative powers at work.  Aquinas goes further, however.  He would argue that human rationality complements and goes beyond the biological to determine which biological desires should prevail over others (thus, Aquinas’s theory of the virtues).  Sometimes biological desires conflict.  Reason determines which impulse should be allowed to prevail.  Human reason corresponds to a Good that is itself spiritual (human reason is a spiritual faculty).  As Aquinas says, “By the intellectual appetite we may desire the immaterial good, which is not apprehended by sense such as knowledge, virtue, and the like.”[39]  Human nature is a necessary component to morality, but it is by no means a sufficient component.[40]  Indeed, what is needed in conjunction with human nature is God’s moral law.  “Aquinas,” Boyd says, “maintains that we pursue the goods of the sensual appetite not as the good qua good but as fulfilling some aspect of our sensual nature.  As a result, the attainment of our sensual desires can never satisfy us as rational beings.  The rational desire for truth, especially truth about God, propels us beyond the merely biological.”  What is more, “A closely related point is that although the sensual inclinations are part of our nature, they themselves are not moral.  It is the existence of reason that enables humans to make moral judgments that differentiate them form nonhuman animals who share the same sensual appetites.”[41]  Aquinas’s anthropology provides a philosophical depiction showing the continuity and discontinuity between animals and humans.  But the principles of rational life are distinctive to human persons alone.        

Now in response to this synthesis atheists have been notorious for noting that chance—a staple of the blind processes of natural selection—is in opposition to the teleology presupposed in Aquinas’s anthropology.[42]  Chance, they say, is in opposition to design.  But this wholly is mistaken.  As Benedict Ashley explains: “The reality of chance does not contradict natural law, since by chance we mean that one thing acting lawfully according to it nature interferes with the behavior of another thing acting lawfully according to its nature.”[43]  Although chance is often seen as contrary to purpose (human nature is pointed toward an end and so has purpose in Aquinas’s view), it is impossible for the nonpurposive cause known as chance to give rise to another set of beings (and all beings are, by definition, purposive; beings have ends, namely, to be).[44]  All beings are “fighters for ends,” as William James once put it.  To put this in other terms, there is no causal power in chance—it is merely the intersection of certain lines of causality.  “Of course,” says Ashley, “it is possible that there may be still a third law that regulates the interference of the two other agencies in a uniform manner.  If this is the case we have a complex system of causes.”[45]  

Chance, then, is a merely word to cover up our ignorance.  Simply because we do not know what the cause is would not mean that there is no cause at all.  Keith Ward adds: “. . . we cannot rule out the existence of causal influences that are undetectable by us, and which may be non-computable.  We can never be sure that we have specified all causally relevant properties exhaustively.”[46]  R.J. Russell concurs: “We speak of this kind of chance when we do not know, or prefer to ignore, the underlying causal factors—while believing they are there in principle.  We could in principle give a complete causal—i.e., deterministic—description of natural processes from the cells to galaxies; we chose a statistical description merely out of convenience.”[47]  On the level of scientific investigation we can say that organisms have certainly evolved through a chance process.  What we are dealing with in chance is human uncertainty, not indeterminism.  Moreover, there is much more to explaining reality than just science.[48]  As I mentioned earlier, one can appeal to final causes which are outside of the province of science.  This is wholly in line with Aquinas’s thought.

In conclusion, Thomistic natural law thinking is completely compatible with sociobiology—that field of science that seeks to understand morality from the biological perspective.  “Unlike other philosophical theories,” Craig Boyd states, “especially those that appeal to divine commands or linguistic analysis, natural law morality stresses that any account of morality must recognize the importance of the biological.”[49]  Hence, the Thomistic concept of natural law is compatible with modern day conceptions of evolutionary ethics.  The pertinent science stresses the organism’s need to survive, reproduce, and cooperate with other members of the species to further human flourishing.  Natural lawyers would agree with this contention and push the issue further: humans have the faculty of reason and therefore must refer to God to determine which biological drive should be allowed to prevail over the others.  Some components of the natural law position transcend purely sociobiological considerations.  Some sociobiologists recognize that sociobiology cannot sufficiently account for all of morality.  As Harry Plotkin, an evolutionary psychologist, writes: “Underlying all the biological and social sciences, the reason for it all, is the ‘need’ (how else to express it, perhaps ‘drive’ would be better) for genes to perpetuate themselves.  This is a metaphysical claim, and the reductionism that it entails is . . . best labeled as metaphysical reductionism.  Because it is metaphysical it is neither right nor wrong nor empirically testable.  It is simply a statement of belief that genes count above all else.”[50]          

A Practical Test Case: Evolutionary Ethics In Support of Pro-Life Positions

The time is ripe for Christian bioethicists to listen to scientists in order to have scientifically informed moral explanations.[51]  It is unfortunate that so many bioethicists have not only refused to consider how evolutionary ethics is compatible with natural law thinking, but also with how it applies to real life ethical debates.  There are at least three relevant scientific truths that are relevant to our inquiry.  First, evolutionists, whether they are atheists or not, insist that one of the primary impulses in all of human life is to find a mate, reproduce with them, and pass on their genes (this holds true whether persons conscientiously realize this or not).  Second, evolution ensures that parents will naturally seek to protect their offspring so that they will eventually grow up and flourish later on in life to pass on their genes as well.  Similarly, relatives to the parent and child (or those who are genetically close to the parents and his or her offspring) will genuinely seek to protect these children from harm, helping them to mature.  With this evolutionary picture in mind (which is applicable to all human beings), it is strange that atheistic evolutionists would argue that abortion should be allowed and even legalized.  On the face of it, abortions are anti-evolutionary.  Why, then, do they insist that abortions should be permitted? 

Atheists conclude that aberrant behaviors, such as abortion, are to be expected from time to time.  Given these exceptions, which are sheer biological givens, we cannot endorse and uphold a pro-life stance.  According to them, exceptional cases cannot be shown to be objectively wrong.  Descriptions of behavior are subtly transcribed into moral prescriptions to fit a pro-choice stance.  Natural lawyer J. Daryl Charles sees the implications: “Without binding moral principles, eventually anything and everything becomes negotiable—from abortion and fetal tissue research to mechanical reproduction and eugenics to euthanasia.  All forms of bioethical discrimination and manipulation can be justified, not merely for the sake of quality of life principles but also against life itself.”[52] 

Throughout this essay I have shown in at least three ways that atheistic interpreters of evolution are exalting “quality of life” principles at the expense of “sanctity of life” principles.  Human beings, in the atheistic evolutionary view, differ from animals in degree and not in kind.  As Craig Boyd puts it, “Since there is no teleology operative in evolution, evolutionary processes simply conform to the principle of natural selection.  As this applies to all human beings, we see that human nature is not constant over time but simply a temporary phase in a continually evolving process.”[53]  For reasons we have already discussed, we cannot resort to strictly utilitarian and/or egoistic ethical views (like the atheists have done, excluding final causes and free will). 

Rather, there are some acts that are intrinsically worthwhile to perform even if they do not lead to anything of value.  The foundation of moral norms is a set of axiomatic necessary moral truths.  Although one does not have to believe in the Christian God in order for someone to recognize their moral duties, we cannot make sense of them unless there is a God who grounds them.  There is a difference between moral epistemology and moral ontology (the latter being of interest to us).  Consequently, not only can all normally functioning persons recognize that objective moral truths exist without believing in God, but everyone should be able to know and abide by them even if nobody else recognizes them as such.  Through the providential workings of natural selection, human beings are able to know and abide by objective moral norms.  Certainly, evolution has made us fit to reproduce, enjoining us to be moral at the same time in order for this process to endure.  In the words of ethicist Mikhael Stenmark:

“A better explanation of much moral belief and behavior is therefore that gradually, as we evolved from our pre-human ancestors, our brain grew and we began to reason to a degree no other animals had achieved, and it is the possession of this ability that make possible not only science, but also morality and our questions about which curse of action are for the best.  These ideas about which courses of action are then spread non-genetically through cultural transmission or communication, and people have become convinced that slavery is morally wrong, that women ought to be given equal opportunities and responsibilities to men, that other living things besides humans have moral standing and so forth.”[54]  

Seen in this way, the natural moral law is not just the effect of practical reason, but includes the preconditions that make informed moral decisions possible to begin with.  Humans must be a certain type of creature to discern and act in response to the demands of the natural moral law.  Coupled with a theory of the virtues, persons will be able to determine which biological desires should be suppressed and/or appeased.   

That evolution propels us to reproduce and protect our offspring is not in dispute.  Now we must turn to the ways in which the natural moral law, which is complementary with evolutionary ethics, is thought to impel persons to embrace the pro-life position.  For one thing, natural moral law theorists maintain that all normally functioning individuals can know what is right from what is wrong.  We cannot not know these basic moral truths.  One of these truths, it may be added, is that pro-life is to be preferred.  

In the case of abortion, it must be admitted that most women who consider having an abortion at least think that they are pregnant with a baby and not an impersonal thing.  Secondly, no matter what culture or time people have live in, the consensus of humanity has upheld the idea that all persons have inherent dignity, sanctity, and worth.  The same principles apply to persons in the womb.  In point of fact, the mere probability that a person is involved in the womb suffices to impel ethicists to not use any means of intervention aimed at aborting the embryo.  Given the belief in a universal human nature, the zygote is an actual human person (and not just a potential person) in the same way that an infant or a toddler is a person with the potential to become a mature as a person.  Thus, the crucial question is “Are we different in kind from animals or not?”  If we are different in kind from animals, then the pro-life view follows as the preferred view.  As J. Daryl Charles points out, most of our culture’s ethical and bioethical disputes are first determined by the way we view the nature of humanity.[55]  If one seeks to uphold the existence and knowability of natural moral principles alone, then they can know that abortion is wrong.  As Professor Charles rightly claims:

“Affirming objective moral truth—as witnessed to by the natural moral law—yields the common moral judgment to protect and dignify human life, and particularly vulnerable human life.  Given our commitment to the intrinsic dignity of the human person, we are forbidden categorically form eliminating it.  There is a moral line that connects the human embryo, fetal destruction, euthanasia, slavery, genocide, and totalitarian rule.  If it is agreed that we never take the life of an innocent human, at any developmental stage and regardless of its functionality, then intentionally taking life at any point along the life spectrum for any reason will always be wrong.  It is wrong not merely because the Christian church or the Bible teaches that it is wrong but because the moral law ‘written on the heart’ of every human, witnesses to its wrongness.”[56]      

Furthermore, the precepts of the natural moral law are complemented and brought to fulfillment by authoritative, divine revelation.  Although one can know that abortion is wrong apart from this revelation, natural lawyers argue that reason can lead persons to conclude that God is the type of God who would reveal himself in human history to clarify and reinforce the precepts of the natural moral law.  According to St. Thomas Aquinas, there are four reasons to think that God would reveal himself in history:

“Besides the natural law and the human law it was necessary for the directing of human conduct to have a Divine law.  And this for four reasons. 

First, , . . . since man is ordained to an end of eternal happiness which is inproportionate to man’s natural faculty . . . therefore it was necessary that, besides the natural and the human law, man should be directed to his end by a law given by God.

Secondly, because, on account of the uncertainty of human judgment, especially on contingent and particular matters, different people from different judgments on human acts; whence also different and contrary laws result.  In order, therefore, that man may know without any doubt what he ought to do and what he ought to avoid, it was necessary for man to be directed in his proper acts by a law given by God, for it is certain that such a law cannot err. 

Thirdly, because man can make laws of those matters of which he is competent to judge.  But man is not competent to judge of interior movements, that are hidden, but only of exterior acts which appear: and yet for the perfection of virtue it is necessary for man to conduct himself aright in both kinds of acts.  Consequently human law could not sufficiently curb and direct interior acts; and it was necessary for this purpose that a Divine law should supervene. 

Fourthly, because . . . human law cannot punish or forbid all evil deeds: since while aiming at doing away with all evils, it would do away with many goods, and would hinder the advance of the common good, which is necessary for human intercourse.  In order therefore, that no evil might remain unforbidden and unpunished, it was necessary for the divine law to supervene, whereby all sins are forbidden. “[57]     

Aquinas’s first prong in the argument for God’s intervention in history consists of those reasons that can be utilized apart from the influence of divine revelation to show that God is the type of God who would want to become a human and do certain types of things that God would do in human history.  These are a priori reasons arise from God’s nature and from the general condition of the human race.  Elsewhere, Aquinas affirms the necessity of divine revelation with respect to the precepts of the natural moral law:  

“It is necessary for man to accept by faith not only things which are above reason, but also those which can be known by reason: and this involves three motives.  First, in order that man may arrive more quickly at the knowledge of Divine truth. . . . Second, . . . in order that the knowledge of God may be more general.  For many are unable to make progress in the study of science, either through dullness of mind, or through having a number of occupations and temporal needs, or even through laziness in learning, all of whom would be altogether deprived of the knowledge of God, unless divine things were brought to their knowledge under the guise of faith.  The third reason is for the sake of certitude.  For human reason is very deficient in things concerning God.  A sign of this is that philosophers in their researches, by natural investigation, into human affairs, have fallen into many errors, and have disagreed among themselves.  And consequently, in order that men, might have knowledge of God, free of doubt and uncertainty, it was necessary for divine matters, to be delivered to them by way of faith, being told to them, as it were, by God Himself Who cannot lie.”[58]

The need for a revelation is a recurrent theme for Aquinas.  He opens up the Summa, asking himself whether there is any further revelation that is required for morality and thus for salvation.[59]  The main reason why human beings need revelation is to know the precepts of the natural law clearly and with certainty. 

The biblical teaching, according to Charles, indicates that abortion is wrong: “At the core of Judeo-Christian moral tradition is the proscription against taking innocent life (Gen. 9:5-6; Exod. 20:13; Deut. 5:17; Matt. 5:21; Rom. 13:9; James 2:11)—a proscription that undergirds civilized society.  The reason for this is that life is inherently sacred (Gen. 1:26-27; 9:5-6).”[60]  Indeed, “As borne out by Hebrew grammar, the sixth commandment is an absolute proscription not against all killing but against the taking of innocent life.  Excluded from the command are the killing of animals, war that is justified, the execution of criminals, and killing in self-defense.”[61]  The Magisterium, which is considered by Catholics as the authentic interpreter of the biblical revelation, has always taught that direct abortion is wrong at every stage in the embryo’s life.  The Fathers of Vatican II, in the Pastoral Constitution in the Modern World, maintain that “life must be protected with the utmost care from the moment of conception: abortion and infanticide are abominable crimes.”[62]  The Instruction on Bioethics in 1987 declares that the “human being is to be respected and treated as a person from the moment of conception; and therefore from the same moment his rights as a person must be recognized, among which in the first place is the inviolable right of every innocent human being to life.”[63]  Pope John Paul II condemned abortion in Evangelium Vitae: “I confirm that the direct and voluntary killing of an innocent human being is always gravely immoral.  This doctrine, based upon that unwritten law which man, in the light of reason, finds in his own heart (cf. Rom. 2:14-15), is reaffirmed by Sacred Scripture, transmitted by the Tradition of the Church and taught by the ordinary and universal Magisterium.”  Further, “Nothing and no one can in any way permit the killing of an innocent human being, whether a fetus or an embryo, an infant or an adult, an old person, or one suffering from an incurable disease, or a person who is dying.”[64]  Many more citations could be given.  The point is that the Magisterium continues to affirm the sanctity of life, making the precepts of the natural moral law clear and binding.

Not only is evolutionary theory able to be reconciled with the dictates of the natural moral law, it is actually complementary with the pro-life view.  Certainly, evolution tells us that the human desire to reproduce and pass on our genes to subsequent generations offers a glimpse as to what position should be preferred: pro-life.   Even if one did not consider these conclusions, which are purely scientific, we would be able to recognize that natural moral law enables us to know that abortion is wrong.  Lastly, revelation teaches that direct abortions are wrong as well.  Thus, the pro-life position should be preferred.  This final conclusion is warranted by evolution, natural law, and divine revelation, all of which, as I have shown, are compatible with one another.       

Conclusion                           

Although some scientists and philosophers have affirmed that ethics can be completely explained in terms of the theory of evolution, there are many problems that attend to this view.  Moreover, natural law morality is consistent with biological evolution and must be preferred over naturalistic interpretations of the theory.  After this much was accomplished in this essay, I turned to a practical case to show that evolution does not necessitate the overthrow the framework of Judeo-Christian paradigm of ethics.  Despite the protests to the contrary, evolutionary ethics is not only consistent with natural law thinking, but is actually complementary with the pro-life view in the abortion debate.