Trolleyology and Rawlsian Moral Grammar

 

                                                               Trolley Problem 1: Spur

 

                                                          Trolley Problem 2:  Footbridge


You are walking along the tracks of a trolley in San Francisco.  You notice that there is a runaway trolley that will kill five people who have become somehow bound to the tracks.  You also notice that there is a switch that will turn the trolley onto a side track, a spur, and thus save the lives of the five people.  Unfortunately, however, there is one person bound to the side track, and so if you throw the switch, he will be killed.  Should you throw the switch?

On another day, you are walking on a footbridge over the tracks.  You see another runaway trolley speeding toward five people bound to the track.  This time, there is no possibility of switching the trolley to a side track.  You could jump onto the track to try to stop it, but you are such a small person that you probably could not stop the trolley.  You notice that there's a big fat man on the bridge who is big enough to stop the train if you push him onto the track.  Should you push the fat man?

These stories might seem too cartoonish to be taken seriously as moral dilemmas.  But in recent decades, ever since they were first proposed by philosophers Philippa Foot and Judith Jarvis Thomson, they have become some of the most debated thought experiments among moral philosophers.  They have also been introduced into scientific experimentation conducted by philosophers, psychologists, and neuroscientists to test whether our moral intuitions about the trolley problem manifest an innate and universal moral sense shaped by human evolution and written into the neural circuitry of the brain.  This shows how a fundamental question in moral and political philosophy can be translated into experimentally testable propositions.  This trolleyology (as it has been called) has become a crucial part of the recent movement towards "experimental philosophy."

An engaging survey of this research has recently been published--Would You Kill the Fat Man? by David Edmonds (Princeton University Press, 2014).  The book elaborates an article by Edmonds that is available online.  A book by John Mikhail--Elements of Moral Cognition: Rawls' Linguistic Analogy and the Cognitive Science of Moral and Legal Judgment (Cambridge University Press, 2011)--shows how this research might confirm Rawls's account of moral knowledge as an innate moral sense analogous to what Noam Chomsky in linguistics has identified as the Universal Grammar that is innate in the minds of all normal human beings and allows them to learn any language.  This research has provoked a lot of criticism.  One of the most interesting lines of criticism comes from the Kantian utilitarian Peter Singer--in "Ethics and Intuitions," The Journal of Ethics 9 (2005): 331-52, which is available online.

Of the hundreds of thousands of people all around the world who have participated in formal trolley problem surveys, most people (up to 90% in some studies) would divert the trolley in the Spur case, but they would not push the fat man in the Footbridge case.  What is most striking about this is that most people react differently to the two cases although pulling the switch and pushing the fat man have identical consequences--one person dies to save five.

Joshua Greene and his colleagues have used brain scanning (functional magnetic resonance imaging) to study the brains of people as they think about trolley problems.  He found that there was a kind of neural wrestling between the calculating and emotional parts of the brain.  Responding to the Spur problem, most people decide to pull the switch, and the more calculating areas of the brain are active (the dorsolateral prefrontal cortex and the inferior parietal lobe), suggesting that they are calculating costs and benefits.  But in response to the Footbridge problem, most people decide that they cannot push the fat man, and the more emotional areas of the brain are active (amygdala, posterior cingulate cortex, and medial prefrontal cortex), suggesting that the idea of pushing the fat man is triggering emotional alarms.  For centuries, moral philosophers have argued about the relationship between moral reason and moral emotion in moral judgments.  Now, it seems, we can see that complex interaction between reason and emotion in the human brain.

For a Kantian utilitarian like Singer, the relevant moral principle in the trolley problem--that five deaths are worse than one death--is the same in both cases, and therefore Singer would pull the switch and push the fat man.  For Singer, the 10% of the people who would push the fat man are rightly following pure moral reason, while the other 90% are allowing their emotions to override their reason, because from the viewpoint of pure reason, there is no morally relevant difference between the two cases. 

Singer concedes that the reluctance to push the fat man probably shows a naturally evolved emotional predisposition against intentionally and directly killing an innocent person, even when such killing will save more lives.  But for Singer that only shows that moral reason should overcome the irrationality of our evolved psychology.  The fact that most people would not push the fat man is irrelevant to the normative question of what they ought to do.  Unlike the empirical sciences (such as the evolutionary science and neuroscience of human nature), normative moral and political philosophy belongs to a realm of pure reason that transcends the natural world of observable experience.  For these reasons, Singer rejects Rawls's claim that moral theory must be rooted in a moral psychology of moral intuitions.

In Section 9 ("Some Remarks About Moral Theory")  of A Theory of Justice, Rawls compared moral theory to Chomsky's linguistic theory that acquiring language depends on a Universal Grammar innate in all human beings.  Just as there might be an innate "sense of grammaticalness" that makes language possible, Rawls suggested, there might be an innate "sense of justice" that makes the practice and theory of justice possible (46-47).  And just as scientific linguists like Chomsky judge the truth of their linguistic theories by how well they explain the data of our linguistic practices, likewise moral philosophers can judge the truth of their moral theories by how well they explain the data of our moral judgments.  We must strive for "reflective equilibrium," Rawls argues, in which our general principles and our individual judgments about particular cases are in harmony.  We might have to revise our principles or revise our judgments until we reach some coherence between them, just as scientists revise their theories or reconsider their data until they reach sufficient harmony between theory and data.

Mikhail argues that Rawls was right to assert that moral theory can be rightly modeled on aspects of Chomsky's theory of Universal Grammar, and that the experimental study of how people solve trolley problems can uncover the Universal Moral Grammar that is innate in the minds of all normal human beings.  Just as there are some general principles of grammar innate in the minds of all normal language users making linguistic judgments, there are some general principles of justice innate in the minds of all normal moral agents making moral judgments.

Rawls argues that this moral grammar supports "justice as fairness" as grounded on the two principles of justice, including the difference principle.  Mikhail, however, is completely silent about these Rawlsian principles; and in place of these principles, Mikhail substitutes the legal norms of homicide and battery as manifested in the trolley problems and in legal tradition.

The trolley problems involve both homicide (the killing of one person to save five people) and battery (the pushing of the fat man).  Mikhail claims that the general principle that accounts for how most people solve the trolley problems is the principle of double effect as stated by Thomas Aquinas.  While the killing of innocent people is generally prohibited, killing can be permissible if the deaths are foreseen but not directly intended and if there are good effects from this that outweigh the bad effects.  So, for example, if I kill in self-defense or in defense of the lives of others, and if the death of the victim is only a side-effect of my actions rather than a directly intended end, then the killing might be permissible.  Mikhail generalizes this principle to cover homicide and battery: "the principle holds that an otherwise prohibited action, such as battery or homicide, which has both good and bad effects may be permissible if the prohibited act itself is not directly intended, the good but not the bad effects are directly intended, the good effects outweigh the bad effects, and no morally preferable alternative is available" (149).  To apply this principle, we need to distinguish means, ends, and side-effects.

This allows Mikhail to explain the morally relevant distinction between the Spur case and the Footbridge case.  In the Spur case, the bystander creates a bad effect (the killing of the man on the spur) only as a side effect.  We know this, because we assume that if the man on the spur were able to free himself before he was hit by train, the bystander would prefer this.  The bystander directly intends to save the five people, but he does not directly intend to kill the man on the spur, although this is a foreseeable consequence.  The bystander must also assume that the bad effect of killing the man is outweighed by saving the five, and that there is no morally preferable alternative (such as throwing some object on the tracks to stop the trolley).

By contrast, Mikhail notes, if we suspected that the bystander was looking for a chance to murder the man on the spur, and so he used the runaway train as an excuse for switching the train towards his intended victim, then this might be considered intentional homicide.

The Footbridge case differs from the Spur case in one respect.  The bystander's pushing of the fat man is a directly intended battery and not just a foreseeable side effect, which most people judge to be forbidden.

But what should we say to Singer's objection to all this, which Mikhail calls "the objection from insufficient normativity" (188)?  The descriptive adequacy of Mikhail's account of how people respond to trolley problems says nothing, Singer complains, about the normative adequacy of our principles in deciding how people ought to respond to trolley problems.  Justifying moral principles is not the same as describing moral intuitions.  Normative moral theory is looking for universal and eternal principles of what is morally right or wrong that are true independently of what human individuals or human cultures believe to be right or wrong.  When Rawls appeals to the moral intuitions that are common among people who live in liberal democratic societies, Singer observes, he becomes a cultural relativist, so that liberal principles of justice are regarded as true only because they happen to be accepted in liberal cultures.  When Rawls suggests that there might be a universal moral sense that is expressed in liberal moral intuitions, and when Mikhail provides empirical evidence for this, this might escape the charge of cultural relativism; but this universal moral sense as imprinted in human psychology by human evolution is still only subjective, lacking in any objective truth, because it's a psychological projection of the evolved human mind rather than an objective truth about the universe.

Mikhail's response to Singer's objection is to admit that, yes, the moral grammar of human nature as a product of evolutionary history imprinted on the human brain is a projection of human psychology that has no mind-independent reality outside of the human mind.  If human beings did not exist as the kind of moral animals that they are, then their human morality would not exist.  Thus, there is no sharp distinction between the normative and the empirical, because normative morality is a projection of our empirical psychology.

The evolved rules of morality are more like the rules of baseball than the laws of physics:  the rules of baseball must be created by human beings, but the laws of physics exist independently of human beings.

What alternative is there?  Singer says that we need a cosmic morality--eternal and universal principles of right and wrong that are somehow woven into the frame of the universe and discoverable by human reason just as we discover principles of mathematics as somehow inherent in the structure of the cosmos.  But Singer never gives a clear explanation or proof of how this could be the case.  Notice that in his essay on "Ethics and Intuitions," he says that we need to prove the objective truth of morality as based on "pure reason" without intuition or emotion, but he indicates that no philosopher has ever successfully done this, and he will not do it himself.

In fact, as I have indicated in a previous post, Singer now admits that after many years of trying to prove that morality can be objectively true and rationally based, without any necessary foundation in evolved human psychology, he has failed, and so he doubts his previous arguments for a Kantian utilitarianism.  But, amazingly, after making this admission, he reaffirms "the existence of objective moral truths."  Although his Platonic longing for an eternal Idea of the Good has been frustrated, he still cannot give it up.

I say--better to be a satisfied Darwinian than a dissatisfied Platonist.

Some of these points are elaborated in other posts here, here, and here.

What Do People Really Do in a Realistic Trolley Dilemma Experiment?

You are walking along the tracks of a trolley in San Francisco.  You see a runaway trolley that will kill five people who have become somehow bound to the tracks.  You also see that there is a switch that will turn the trolley onto a side track, a spur, and thus save the lives of the five people.  Unfortunately, however, there is one person bound to the side track, and so if you throw the switch, he will be killed.  Should you throw the switch?

On another day, you are walking on a footbridge over the tracks.  You see another runaway trolley speeding toward five people bound to the track.  This time, there is no possibility of switching the trolley to a side track.  You could jump onto the track to try to stop it, but you are such a small person that you probably could not stop the trolley.  You notice that there's a big fat man on the bridge who is big enough to stop the train if you push him onto the track.  Should you push the fat man?

Oh, I know, this runaway trolley scenario sounds too cartoonish to be taken seriously.  But it does capture the moral dilemma that people can sometimes face--perhaps in war--when it seems that some people must die to save the lives of many more.  Although killing someone is usually wrong, there are circumstances in which killing is justifiable--such as killing in self-defense or in defense of the lives of others.

Of the hundreds of thousands of people all around the world who have participated in formal Trolley Dilemma surveys, most people (80% to 90% in some studies) would divert the trolley in the Switch Case, but most of them (around 75%) would not push the fat man in the Footbridge Case.  As reported by Paul Bloom (in Just Babies, 167-68), even three-year-old children presented with the trolley problem (using Lego people) will tend to say that throwing the switch is right, but pushing the man off the bridge is wrong. What is most striking about this is that most people react differently to the two cases although pulling the switch and pushing the fat man have identical consequences--one person dies to save five.  Why?

Joshua Greene thinks that if you scan the brains of people with fMRI while they are deciding this Trolley Dilemma, you will see the neural activity that explains why people decide this the way they do; and this will reveal the neural correlates of moral judgment.  Previously, I have written about the Trolley Dilemma (here and here) and about Greene (here, here, and here).  Recently, I have been thinking more about this as possibly showing how conscience and guilt arise in the brain.

But right now I am wondering whether what people say they would do in the hypothetical Trolley Dilemma situation shows us what they would actually do in a real Trolley Dilemma situation.

As far as I know, the first realistic Trolley Dilemma experiment was done by Michael Stevens for his "Mind Fields" YouTube video series here  It's about 35 minutes long.  This video is entitled "The Greater Good," and it was Episode 1 of the second season, which first appeared online December 6, 2017.

The experiment is clever.  Seven people were recruited to participate in a focus group for the "California Rail Authority" (a fictitious organization).  They think they will be asked questions about what they would like to see in high-speed rail transportation.  When they arrive for their meeting, at a CRA trailer on a hot day, each individual is told that there is going to be a 15 minute delay, and while they are waiting, they can sit in an air-conditioned remote railway switching station.

Inside the switching station, they meet a switchman who sits before a panel of screens with (apparently) live pictures of a remote railway switching location.  The switchman explains how he switches a train from track 1 to track 2.  A train is coming through, and he has the duped subject actually switch the train onto track 2.  Then the switchman receives a phone call, and he says he has to leave for a short time, but the subject should stay in the switching station.  What the subject does not know is that what he sees on the video screens is all prerecorded, and the switchman is an actor.  The subjects do not know that everything they do is being filmed by hidden cameras.

Sitting alone in the switching station, the subject sees railway workers walking onto the tracks, and hears a loud warning "objects on the tracks."  One worker walks onto track 2, and he appears to be distracted by taking a telephone call.  Five workers walk onto track 1, and they are wearing sound-proofing earphones.  All the workers have their backs turned to the train that is shown approaching, and the subject sees this train coming and the warning "a train is approaching" on track 1.  The workers do not seem to see or hear the approaching train.  So the subject must think that the 5 men on track 1 will be killed unless the train is switched onto track 2, so that 1 man will be killed.  Should the subject pull the switch?

You might think this is an unethical experiment.  Isn't it wrong to trick people into going through such a traumatic experience?  After consulting with psychologists, Stevens decided this would be an ethical experiment as long as they screened the people they recruited and excluded those who showed the personality traits that might predispose them to be excessively traumatized by the experiment.  He also designed the experiment to minimize the traumatic effects.

7 individuals went through the experiment.

The first was Elsa.  When she was left alone in the switching station, and she saw the train approaching the men on the tracks, she became visibly disturbed as she intently stared at the screens.  Just a few seconds before the train would have hit the 5 men on track 1, she switched the train onto track 2, expecting that the one man would then be killed.  But as soon as she pulled the switch, the screens went blank, and this message was flashed on the screen:  "End of test.  Everyone is safe."  She did not actually see the man on track 1 being hit.  And immediately Stevens and a psychologist entered the building and told her that this was all an experiment, and all these people were actors.

They asked Elsa about what she was feeling and thinking.  She was frightened by what she saw on the screens.  "Their lives are in my hands," she thought.  "I must save more lives."  "I didn't know if I made the right decision. . . . But a life is a life."

When people are asked to make a decision about flipping the switch in the hypothetical Trolley Dilemma, most of them agree with Elsa and decide to kill one person to save five.  Surprisingly, however, in this experiment, in which people thought they were really deciding life or death, most of the participants--5 out of 7--refused to flip the switch.  The five people that came after Elsa all froze in fear as they watched the train approaching the men, and so these five refused to flip the switch.

Afterwards, each of the 5 said that they felt terrified, and they froze up so that they could not move their hands to the switch.  "I thought about it, but I couldn't do it," one said.  They all suggested that they had fleeting thoughts that surely the men would somehow escape from being killed.  Surely the workers would notice the train and jump away.  Or maybe the train had sensors that would stop it to avoid hitting them.  Or maybe there are other railway people watching over this scene who can stop the train.  They were looking for some way to escape the tragic inevitability of the choice between one dying and five dying.  One person said: "I didn't know who should live, who should die. . . . Switching or not, someone would be hurt."

The last of 7 in the experiment was Cory, and like Elsa, he flipped the switch.  But we see and hear him talking to himself: "Oh no. . . . They should see this. . . . Oh my God!"

We see the terror in Cory's face, and afterwards he expresses how horrified he felt in taking responsibility for his decision.  "5 people versus 1," he says.

Cory burst into tears once Stevens and the psychologist came into the building.  He was clearly distraught by what he had done.

I know we probably shouldn't draw conclusions from an experiment involving only 7 individuals, but I will go ahead anyway and draw three conclusions.  First, this experiment suggests that for most people, what we think we would do in a moral dilemma like this differs from what we would actually do.  Most of us decide the hypothetical Trolley Dilemma by saying that we would flip the switch, and thus endorse the utilitarian calculation that taking one life to save five is the "greater good."  But if we were in a real tragic situation like this--or one that we thought was real--most of us would freeze, refusing to kill the one man to save five.

If this is so, how do we explain it?  Was there something about Stevens' experiment that made the flipping of the switch feel like a "personal" harming of the one man on track 2--making it feel more like the pushing of a fat man off the footbridge into the path of the train?  If Stevens could have scanned the brains of these 7 people during the experiment, would he have seen that the more emotional parts of the brain (amygdala, posterior cingulate cortex, and medial prefrontal cortex) were active, countering the more calculating parts of the brain (the dorsolateral prefrontal cortex and the inferior parietal lobe), which is what Joshua Greene and his colleagues in 2001 found in the brains of those deciding the Footbridge Dilemma?

Was there something about the circumstances of Stevens' experiment that made at least five of the seven people feel that flipping the switch would violate the instinctive moral principle of double effect because they would be directly targeting the man on track 2 for death?

My second conclusion is that in a tragic dilemma like this, there is no right choice.  That's what makes it tragic!  So both those who pull the switch and those who don't can feel justified.

Here I seem to disagree with Stevens.  In his closing comments, he asks the question, Is it wrong to freeze?  And he implies that the answer is yes, because he says we can learn to overcome our propensity to freeze to serve the "greater good."  Both he and the psychologist appear to praise Elsa and Cory for having made the right choice.  But I don't see that.  And in the meeting of all the participants at the end, they share their experiences in a way that suggests that those who froze need not feel ashamed of their decision not to throw the switch.

My final conclusion from this experiment is how is shows both reason and emotion in moral judgment.  These 7 individuals had only a couple of minutes to decide the shocking moral dilemma they faced.  But in that short time, they all showed deep emotional disturbance, and they all engaged in some reasoning.  They all assessed the situation emotionally and rationally before making their decision.  This teaches us a general truth about human nature--the moral judgment is both rational and emotional.  But it also teaches us about the individuality of moral decisions in which different people will come to different decisions where there is no clearly right answer.

The Incoherence of Evolutionary Psychology's Kantian Transcendentalist Morality: Carlton Patrick and Peter DeScioli

In Consilience: The Unity of Knowledge (1998), Edward O. Wilson recognized that crucial for his unification of all knowledge was a biological account of ethics as rooted in evolved human nature.  He rightly noted that in doing this, he was following in the tradition of naturalistic ethics that stretches from Aristotle to David Hume to Adam Smith and to Charles Darwin.  He was also right to see this naturalistic tradition of ethics as being "empiricist" in contrast to the "transcendentalist" ethics of those thinkers like Immanuel Kant who look to a transcendent realm of moral freedom beyond the natural world of human inclinations and experience.  Since I agree with Wilson about this, it always seems strange to me that so many evolutionary psychologists have rejected Wilson's reasoning in favor of a Kantian transcendentalist view of morality, even though this contradicts any evolutionary explanation of morality as grounded in evolved human nature, which makes their account of morality incoherent.

For example, a few months ago, I wrote about Carlton Patrick's article--"Evolution Is the Source, and the Undoing, of Natural Law"--in which he assumed that John Finnis was correct in his Kantian interpretation of natural law as based on some "supernatural or metaphysical explanations" that transcend human nature.  Patrick then showed how evolutionary psychology explains that "when we talk about morality, we are not talking about a cosmic mandate but rather a set of species-wide psychological instincts that are a part of human nature."  But in thus refuting Finnis's Kantian distortion of natural law, Patrick ignored the fact that the natural law as understood by people like Thomas Aquinas and John Locke is rooted in human biological nature in a way that can be confirmed by evolutionary moral psychology.

I have also pointed out how Patrick and his coauthor Debra Lieberman have supported a Kantian rationalist view of ethics as transcending human biological nature, which denies the naturalist view of ethics defended by Locke, Darwin, and Westermarck.

Peter DeScioli is another example of an evolutionary psychologist who accepts Kant's transcendentalist morality, while still developing an evolutionary account of morality that contradicts that Kantian transcendentalism (DeScioli 2016; DeScioli and Kurzban 2009, 2013, 2018; Kurzban, DeScioli, and Fein 2012).  DeScioli repeatedly refers to Kant's Groundwork for the Metaphysics of Morals as showing how moral judgment must depend on the "categorical imperatives" of a transcendental morality (see, for example, DeScioli and Kurzban 2013, 479-480; and Kurzban et al. 2012).  He also endorses George Jackson Mivart's Kantian critique of Darwin's evolutionary moral psychology in The Descent of Man (DeScioli and Kurzban 2013, 479; Mivart 1893, 1973).  Mivart insisted on a Kantian separation between nature and morality.  Although the human body could be explained as a natural product of biological evolution, Mivart contended, the human soul was a supernatural product of divine creation.  And as an expression of the soul's transcendence of nature, human morality manifested a uniquely human freedom from natural causality.

In the Groundwork, Kant posits a radical dualism that separates reality into two metaphysical realms.  Judging what is the case belongs to the "phenomenal" realm of nature, but judging what ought to be belongs to the "noumenal" realm of freedom (Kant 1959, 3-5, 30, 44-45, 67-74, 80 [Academie edition, 387-89, 413, 426-28, 448-56, 460-62]).  The distinction in English between is and ought corresponds to Kant's distinction in German between sein and sollen.  For Kant, the natural world is governed by causal laws that can be understood by natural science; and in this world there can be no free will, because every event must be determined by a causal mechanism.  By contrast, in our moral experience, we praise and blame people in accordance with a moral law that transcends nature and is thus unknowable by natural science; and in this moral world we must assume free will, because moral judgment would be impossible unless we assumed that people were capable of freely choosing to obey or disobey the moral law.  As moral agents, we obey categorical imperatives of what ought to be, but this ought expresses a moral necessity that has no place in nature.  "When we have the course of nature alone in view, ought has no meaning whatsoever" (Kant 1965, 473).  As moral agents, human beings transcend the empirical realm of nature and enter a transcendent realm of freedom that belongs to them as rational beings not governed by the laws of nature.

Kant's separation of is and ought treats morality as an autonomous realm of experience governed by its own internal logic with no reference to anything in human nature such as natural desires and inclinations and the natural pursuit of happiness.  The human pursuit of happiness is not truly moral because it is governed by the empirical hypothetical imperatives of prudence--if you desire to be happy, then you must cultivate the moral and intellectual virtues--but not by the categorical imperatives of pure moral reason--you must obey the moral law without regard to your natural desires for happiness.

This puts Kant in opposition to the ethical naturalists like Aristotle, Aquinas, Locke, and Hume, who say that the human good is the desirable, that human morality is the pursuit of happiness, and that the natural moral law corresponds to the order of the natural desires of human nature.

When Darwin developed his evolutionary theory of morality, he adopted the ethical naturalist position rather than a Kantian dualism.  When he began his account of the moral sense in The Descent of Man, he quoted a passage from Kant's Critique of Practical Reason about how the word ought is one of the noblest traits of human beings.  But in the immediately following passage of Kant's book, Kant said this experience of the moral ought shows us "man as belonging to two worlds" (Kant 1956, 90).  Darwin, however, denied this Kantian dualism by indicating that he would approach morality "exclusively from the side of natural history," and he identified the power of the word ought as expressing instinctive moral emotion--"the deep feeling of right or duty" (2004, 120-21, 134, 136, 140, 147, 680).

DeScioli says that his evolutionary theory of morality is on the side of Kant rather than Darwin, because he accepts Kant's claim "that morality consists of 'categorical imperatives,' a set of actions that are morally wrong regardless of the goals these actions are intended to achieve," and DeScioli believes that laboratory research "has found that people often show Kantian moral thinking, focusing on specific actions rather than expected consequences" (DeScioli and Kurzban 2013, 479).   

DeScioli claims that the Kantian morality of categorical imperatives is shown clearly in how most people think about the Trolley Dilemma.  Imagine that you see a runaway trolley speeding down a track, and five people who have somehow become bound to the track will be killed.  You see that there is a switch that will turn the trolley onto a sidetrack and save the lives of the five people.  Unfortunately, however, there is one person bound to the sidetrack who will be killed if you throw the switch.  Should you throw the switch--killing one person but saving five?

Now imagine that you are on a footbridge over the tracks.  You see the runaway trolley and the five people who will be killed if the trolley is not stopped.  There is no switch to divert the trolley onto a sidetrack.  You could jump onto the track and try to stop it.  But let's say that you are such a small person that you're unlikely to stop it.  You notice, however, that there is a fat man standing near you, and if you push him onto the tracks, he will probably stop the trolley, but he will be killed.  Should you push the fat man--killing one person but saving five?

Oh sure, as I have indicated in my previous posts on the Trolley Dilemma, this looks like a silly cartoon.  But it does illustrate the kind of dilemma that some people have faced (perhaps in war), where killing one or a few people might save the lives of many. 

When people are asked about these two trolley scenarios, most will say that they would pull the switch but would not push the fat man.  This might seem strange since most are willing to kill one person to save five in the switch case but not in the footbridge case.  What's the difference between the two cases?

(Actually, in one realistic simulation of the switch case, 5 of 7 individuals froze in fear and refused to throw the switch.)

As DeScioli indicates, the most plausible explanation has been offered by John Mikhail (2011), who says that what we see here is an intuitive moral understanding of the Principle of Double Effect.  Thomas Aquinas stated this principle as part of his natural law jurisprudence.  To reconcile the prohibition of intentional killing with the right to kill in self-defense, Aquinas explained: "Nothing prevents one action having two effects, only one of which is intended, and the other of which is unintended. . . . Therefore, one's action in defending oneself can have two effects: saving one's life and slaying the aggressor.  And so such acts of self-defense, as one intends by them to preserve one's life, do not have the character of being unlawful, since it is natural for everything to keep itself in existence as far as possible" (Summa Theologica, II-II, q. 64, a. 7).  Mikhail sees a general principle here: "the principle holds that an otherwise prohibited action, such as battery or homicide, which has both good and bad effects may be permissible if the prohibited act itself is not directly intended, the good but not the bad effects are directly intended, the good effects outweigh the bad effects, and no morally preferable alternative is available" (Mikhail 2011, 148-49).

Mikhail applies this Principle of Double Effect to explain how most people distinguish the switch case from the footbridge case in the Trolley Dilemma.  If there is no morally preferable alternative, most people would pull the switch to intentionally save the five lives, while foreseeing but not directly intending the death of the one person on the sidetrack.  We know that the killing is not intended, because if the person on the sidetrack could escape and save his life, the bystander who pulled the switch would be pleased with this outcome.  By contrast, to push the fat man off the footbridge would be a directly intended killing; and we know that because if the fat man could run off the track to save his life, the intended outcome of the bystander who pushed him would not be achieved.

Mikhail sees this Principle of Double Effect as one manifestation of an "intuitive jurisprudence" rooted in "a common moral nature" and "a common sociobiological instinct" that illustrates the naturally evolved moral sense identified by Darwin in The Descent of Man (Mikhail 2011, 57, 148, 172; Darwin 2004, 132-38).

I don't see how this conforms to Kant's metaphysical morality.  Kant never speaks about the Principle of Double Effect.  And he clearly denies that moral judgment can be rooted in any instinctive moral sense of human nature, because pure moral reasoning belongs to a noumenal realm of pure moral reason that transcends the empirical reality of nature.

And yet, DeScioli insists that how people judge the trolley dilemma manifests the categorical imperatives of Kantian morality.  "Immanuel Kant would argue . . . that when humans face this dilemma, they should not kill one to save five because there is an inviolable moral rule against killing that cannot be broken regardless of the consequences" (Kurzban, DeScioli, and Fein 2012, 323).  In the footbridge version of the trolley dilemma, most people do seem to judge that in that situation, it is wrong to kill one person to save five people.  But in the switch version, most people judge that in that situation, it is right to kill one person to save five.   And so they do not believe in a Kantian categorical imperative that "there is an inviolable moral rule against killing" in all situations, as DeScioli asserts.  Rather, they believe that the rightness or wrongness of killing depends upon the situation.  So that in a situation where one must kill one person to save five people, and that killing is not directly intended, that killing is not wrong.  But in a situation where one directly intends to kill one person to save five people, that killing is wrong.  

Similarly, in a situation where killing an attacker is the only way to save one's life, that killing in self-defense is not wrong, because one is not directly intending the killing, as indicated by the fact that if the attacker were to retreat or surrender, one would not kill him.  A comparable moral principle of the law of just war is that combatants must not directly intend to target innocent people for attack, although innocent people might die as an unintended side-effect of directly attacking military targets.  Combatants may attack and kill enemy combatants who threaten them, but if those enemy combatants surrender, then they may not be killed.  

Here we see that Kant's categorical imperative (never kill) fails, because it does not allow for prudence in recognizing the variability in our moral judgments of right and wrong as applied to variable situations.

In a recent article in Evolution and Human Behavior, DeScioli seems to pull away from his earlier attempts to ground an evolutionary theory of morality and law in Kantian moral philosophy (De Scioli 2023).  He says nothing about Kant.  He argues that moral rules and laws evolved as a strategy for choosing sides in conflicts by impartial rules of action.  And this would seem to be grounded not in Kant's categorical imperatives but in the hypothetical imperatives of Thomistic and Lockean natural law as rooted in evolved human nature.  I will comment on that article in my next post.

REFERENCES

Darwin, Charles. 2004. The Descent of Man.  Penguin Classics.

DeScioli, Peter.  2016.  "The Side-Taking Hypothesis for Moral Judgment."  Current Opinion in Psychology 7:23-27.

DeScioli, Peter. 2023.  "On the Origin of Laws by Natural Selection."  Evolution and Human Behavior 44: 195-209.

DeScioli, Peter, and Robert Kurzban.  2009.  "Mysteries of Morality."  Cognition 112: 281-99.

DeScioli, Peter, and Robert Kurzban.  2013.  "A Solution to the Mysteries of Morality."  Psychological Bulletin 139: 477-496.

DeScioli, Peter, and Robert Kurzan.  2018.  "Morality Is for Choosing Sides."  In K. Gray and J. Graham, eds., Atlas of Moral Psychology, 177-185.  New York: Guildford Press.

Kant, Immanuel.  1956.  Critique of Practical Reason.  Trans. Lewis White Beck.  Indianapolis: Bobbs-Merrill.

Kant, Immanuel.  1959.  Foundations of the Metaphysics of Morals.  Trans. Lewis White Beck.  Indianapolis: Bobbs-Merrill.

Kant, Immanuel.  1965.  Critique of Pure Reason.  Trans. Norman Kemp Smith.  New York: St. Martin's Press.

Kurzban, Robert, Peter DeScioli, and Daniel Fein.  2012.  "Hamilton vs. Kant: Pitting Adaptations for Altruism Against Adaptations for Moral Judgment."  Evolution and Human Nature 33: 323-333.

Mikhail, John.  2011.  Elements of Moral Cognition: Rawls' Linguistic Analogy and the Cognitive Science of Moral and Legal Judgment.  New York: Cambridge University Press.

Mivart, St. George Jackson. 1893.  "Evolution in Professor Huxley."  The Popular Science Monthly 44: 319-33.

Mivart, St. George Jackson.  1973.  "Darwin's Descent of Man."  In David Hull, ed., Darwin and His Critics, 354-84.  Chicago: University of Chicago Press.

Patrick, Carlton.  2023.  "Evolution Is the Source, and the Undoing, of Natural Law."  Evolution and Human Behavior 44: 175-183.

Wilson, Edward O.  1998.  Consilience: The Unity of Knowledge.  New York:  Knopf.

The Humean Regard for Reason in the Moral Mind: Comments on Joshua May

One of the most interesting developments in the intellectual world over the past 30 years has been the cooperation of scientists and philosophers in applying empirical scientific research to philosophical questions.  I have often argued that empirical science can clarify and perhaps even resolve some of the great debates in moral and political philosophy.  In particular, I have contended that empirical research in Darwinian moral psychology proves that Humean empiricist sentimentalism is right, and Kantian transcendentalist rationalism is wrong. Some of my pertinent posts can be found here, here, here, here, here, here, here, here, and here.

Joshua May's new book Regard for Reason in the Moral Mind (Oxford University Press) argues, on the contrary, that the scientific research in moral psychology that I cite actually does not sustain Hume's sentimentalist ethics, because it supports an anti-Humean rationalism in moral philosophy.  Hume is famous for declaring: "Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them" (Treatise of Human Nature, 2.3.3.4).  May claims, however, that there is nothing in the empirical science of moral psychology that refutes the anti-Humean position "that normative beliefs can causally produce a normal, non-pathological action without merely serving or furthering an antecedent desire. On this picture, we can be motivated to act ultimately by recognizing that it's the right thing to do.  Reason is not a slave to such passions" (179).

I agree with May in rejecting pure sentimentalism (like that promoted by Jesse Prinz), because this ignores the fact that while our emotions or desires motivate our actions, those emotions or desires are prompted and directed by our rational judgment, and thus emotion alone cannot explain our moral actions.

I also agree with May in rejecting pure rationalism (like that of Immanuel Kant), because while reason influences our conduct, pure reason alone cannot move us to act without the motivational impetus of emotion or desire.  Although May does not emphasize or elaborate the point, he clearly rejects the Kantian position that "we can arrive at moral judgments by pure reason alone, absent any sentiments or feelings" (5, 19, 97, 186-87).

What we need, then, is a theory that accounts for the experimental research on moral judgment that shows a complex interaction of reason and emotion.  The best statement of such a theory is Hume's rationalist sentimentalism.  As I indicated in my previous post on Jonathan Haidt, Hume is often mistakenly identified as an irrationalist emotivist.  When Hume declared that "reason is, and ought only to be the slave of the passions," he was not denying the power of reason in moral judgment.  As the context of this remark makes clear, he believed that reason can direct action but not motivate it: "The impulse arises not from reason, but is only directed by it" (1888, 414).  When our passions are accompanied by false judgments, reason can properly correct them: "The moment we perceive the falsehood of any supposition, or the insufficiency of any means, our passions yield to our reason" (1888, 416).  "Reason and judgment may, indeed, be the mediate cause of an action, by prompting, or by directing a passion" (1888, 462).  Consequently, "reason and sentiment concur in almost all moral determinations and conclusions" (1902, 172).  For example, reason might instruct us as to how justice could be useful to society, but this alone would not produce any moral approbation for justice unless we felt a sentiment of concern for the happiness of society (1902, 285-87).

Consider, for example, the research by Joshua Greene (2013) and others who have used functional MRI to scan the brains of people as they make decisions about the Trolley Dilemma.  In the Switch Case, most people are willing to pull the switch to save five lives while taking one life.  But in the Footbridge Case, most people are unwilling to push the fat man onto the tracks to save five lives.  In judging the Switch Case, the more calculating parts of the brain are activated (including the dorsolateral prefrontal cortex), while in judging the Footbridge Case, the more emotional areas of the brain are active (including the ventromedial prefrontal cortex).  

Like many of the thought experiments favored by contemporary philosophers, this Trolley Dilemma is a cartoon story that doesn't seem realistic.  But we could also think about some real cases in history--particularly the history of war--that would present essentially the same dilemma, which comes up in the debates over "just war" reasoning.  As I have indicated in a previous post (here), Winston Churchill and the British war leaders faced a real Trolley Dilemma in responding to Germany's flying bomb attacks on London in the summer of 1944.  The British philosopher who first proposed the Trolley Dilemma--Philippa Foot--lived through these attacks.

Here's Jesse Prinz's interpretation of how people judge the Trolley Dilemma:

"In all these moral dilemmas, there are too options: you can save five people (that's good!), or you can do something that results in one person dying (that's bad!).  When you think about doing something good, you may have a positive emotional response; it feels good to help people.  When you think about doing something bad, your response is negative.  These two emotional forces battle it out in the brain and the stronger one wins." (2012, 297)

Prinz is silent, however, about the point made by Greene and his colleagues that there is no absolute separation between reason and emotion in the brain.  For example, the dorsolateral prefrontal cortex and the ventromedial prefrontal cortex are interconnected, and this confirms Hume insight about the interconnectedness of reason and emotion in moral judgment.

Prinz is also silent about the point made by John Mikhail that the emotional responses to the Trolley Dilemma show an intuitive grasp of the rational principle of double effect, which often figures prominently in just war reasoning.  Mikhail generalizes this principle to cover homicide and battery:  "the principle holds that an otherwise prohibited action, such as battery or homicide, which has both good and bad effects may be permissible if the prohibited act itself is not directly intended, the good but not the bad effects are directly intended, the good effects outweigh the bad effects, and no morally preferable alternative is available" (2011, 149).

Most people think pushing the fat man is wrong because their emotional response against this embodies a rational principle by which a directly intended killing of an innocent person is wrong, while an indirect and unintended killing of an innocent person might be justifiable if it achieves a good effect that outweighs the bad effect.

Emotions are judgments about the world, and thus our emotions are shaped by rational judgments.  So, for instance, in the Switch Case, if we discovered that there was some other way to divert the trolley without killing the one innocent person, we would condemn throwing the switch.

Sometimes it is said that when we see the influence of intuitive emotional reactions in the Trolley Dilemma, this debunks our moral judgments in such cases because it shows that our judgments are biased by irrational emotions.  Utilitarians like Greene and Peter Singer say that the abstract utilitarian principle of killing one person to save five is the same in both the Switch case and the Footbridge case, and so the emotional resistance to pushing the man off the footbridge is morally irrelevant. 

But May rightly observes that this is mistaken, because "integral emotions can alert us to morally relevant factors, so it's not problematic in general to base one's belief on them" (99).  Our emotional aversion to pushing the man off the footbridge to stop the trolley from killing the five people is alerting us to "something like greater agential involvement in the generation of a bad outcome."  As opposed to the Switch case, we are here "harming another actively, purposefully, and in a personal way," which is surely a morally relevant factor (100-101).

But if May sees here the necessary combination of reason and emotion or beliefs and desires in explaining moral action, which is necessary because pure thought by itself cannot motivate us to act without emotion or desire, then it seems that May is actually agreeing with the Humeans in embracing a rationalist sentimentalism.  

May nonetheless insists that while he agrees with the Humeans about the need for combining reason and desire, he disagrees about which comes first: the Humean thinks that reason leads to moral action only when it is guided by an antecedent desire, while the anti-Humean thinks that moral reasoning that is not guided by any antecedent desire can produce a desire that motivates the execution of the moral judgment reached by reason alone.  Unlike the Kantian anti-Humean who thinks that moral reason produces moral action without any need for intrinsic desire, May's anti-Humean thinks that moral reason produces the intrinsic desire that then produces the moral action dictated by reason, and thus reason is the ruler of desire, not the slave.  Thus, May can say that "reason is not a slave to unreasoned desire," because moral reason creates its own reasoned desire to motivate moral action (188).

How exactly does this happen?  May explains: "The process involves ordinary causation: an intrinsic desire is causally generated by a normative belief and the relevant disposition," because "it's partly constitutive of being a rational, virtuous, or strong-willed person that one possesses the disposition to desire in accordance with one's normative beliefs." Notice that May has added a reference to "disposition."  He concedes that "Humeans must say something quite similar.  The only difference is that, instead of a disposition, Humeans posit a full-blown desire," because they believe that "actions are generated by intrinsic desires combined with beliefs about how to satisfy them" (190-91).

The Humeans might complain that May's "disposition" is just another word for desire, so we might as well say that reason is the slave of the dispositions!

May writes:

". . . the best anti-Humean theory merely posits a disposition for normative beliefs to generate the corresponding desires.  While a strong-willed person, for example, may lack the antecedent desire to throw her pack of cigarettes away, she may simply have a disposition to do so if she believes it's best to trash them."

"Humeans may be tempted to count such dispositions as desires and declare victory.  However, while we're working with a rather broad conception of desire, we shouldn't broaden it to any mere disposition of a person to do something.  A desire is a goal-directed, conative, motivation-encompassing state with some content, so it's a state whose function is to bring about what's desired.  But desire is not the sole proprietor of dispositions relevant to action.  To adapt an example from Darwall . . ., even if I'm disposed to eat a piece of pie upon seeing one, this disposition alone need not constitute a desire for some pie.  A mere disposition can graduate to a full-fledged desire only if it has the requisite function and content . . . . Of course, Humeans would explain the eating of some pie in terms of an antecedent desire to eat delicious food when it's available.  However, the pie example is not meant to refute Humeanism but rather to show that being disposed toward some action (e.g., eating pie) doesn't entail antecedently desiring it in particular" (189).

Here May's distinction between disposition and desire seems to be a distinction between a general desire (such as a desire for delicious food) and a particular desire (such as a desire for this piece of pie before me that I judge to be delicious food), where the transition from one to the other requires a rational judgment.  This looks like what Aristotle identified as the "practical syllogism" in The Movement of Animals:  the major premise is a desire for something, the minor premise is a judgment that some action will satisfy that desire, and the conclusion is the execution of the action.  So if I desire healthy food, and if I judge that this piece of pie before me is healthy food, then I will eat it.  May's argument seems to be that my desire to eat this piece of pie is not antecedent to my judgment that this is a good piece of pie.  Rather, my rational judgment that this piece of pie is healthy food appeals to my general disposition to eat healthy food in a way that produces the desire to eat this piece of pie.  But, still, the Humean will say that my rational judgment here is serving my general disposition, which might as well be called a desire.

Since May admits that reason must be combined with a motivating disposition to create a new desire, which then motivates action, it's hard to see that this really differs from the Humean claim that all action requires the combination of reason and an antecedent desire.  May even admits the weakness of his argument:

"Now, I don't pretend to have conclusively ruled out Humeanism as a hypothesis about the structure of motivation.  I only aim to show that moral beliefs play an important role in human action and that we lack empirical reason to always posit antecedent desires that they serve or further.  Perhaps our best theory will require always positing such antecedent desires.  As we saw in the previous chapter, construing moral integrity as involving such antecedent desires isn't always incompatible with virtue anyway" (198).

It's not clear to me how any neuroscientific experiments could resolve this dispute between May's "sophisticated anti-Humeanism" and the Humeans.  The scientific research can refute both pure emotivism and pure rationalism by showing that neither emotion alone nor reason alone can explain our moral psychology, because, as May says, "both reasoning and emotion together play important roles in moral psychology."  But it's hard for scientific research to decide whether reason is prior to emotion or emotion is prior to reason, because once one recognizes the cognitive aspects of emotions as resting on judgments about the world, the line between emotion and reason becomes fuzzy.  May says that "the reason/emotion dichotomy, intuitive as it may be, is either spurious or fruitless" (228).  A Humean like Haidt says the same thing in speaking of the "useless dichotomy between cognition and emotion."  "Emotions are not dumb. . . . Emotions are a kind of information processing" (Haidt 2012, 44-48).  I first saw this in my early studies of Aristotle's Rhetoric, teaches rhetoricians to "reason with the passions" of their audience.

Any experimental testing to resolve this dispute between May and the Humeans would require some agreement on possible scenarios that could be studied.  The anti-Humean Stephen Darwall has offered one good example of what he interprets as an illustration of how moral judgment creates a new desire to execute the judgment without any need for an antecedent desire.  The Humean Neil Sinhababu (2009) accepts this as a good example for study, but he points to evidence that there really is an antecedent desire in the story.  Although May accepts Darwall's argument and rejects Sinhababu's argument, May does not speak about this story.

Here's the story:

"Roberta grows up comfortably in a small town.  The newspapers she reads, what she sees on television, what she learns in school, and what she hears in conversation with family and friends present her with a congenial view of the world and her place in it.  She is aware in a vague way that there is poverty and suffering somewhere, but sees no relation between it and her own life.  On going to a university she sees a film that vividly presents the plight of textile workers in the southern United States: the high incidence of brown lung, low wages, and long history of employers undermining attempts of workers to organize a union, both violently and through other extralegal means.  Roberta is shocked and dismayed by the suffering she sees.  After the film there is a discussion of what the students might do to help alleviate the situation.  It is suggested that they might actively work in promoting a boycott of the goods of one company that has been particularly flagrant in its illegal attempts to destroy the union.  She decides to donate a few hours a week to distributing leaflets at local stores." (Darwall 1983, 39; Sinhababu 2009, 483-84)

According to Darwall, this shows that Roberta's decision to support the boycott arose from her moral judgment that the workers were suffering from unjust exploitation, which created the desire that these workers not suffer, and this new desire then motivated her to act in accordance with her moral reasoning.  Contrary to what the Humeans would say, there was no antecedent desire guiding her moral reasoning, but instead her moral reasoning created a new desire to motivate her moral action: her passions were the slave of her reason.

But why, Sinhababu asks, is Roberta "shocked and dismayed by the suffering she sees"?  Aren't those emotions of shock and dismay evidence of an antecedent desire that human beings should not suffer unfairly?  This general desire that people not suffer could then be turned into the particular desire that the workers in the South should be relieved from their suffering once she understood the film's  presentation of the information about their suffering.  So here her moral desires guided her moral reasonng to moral action.  Her desire that humans not suffer was latent in her mind until it was activated by the judgment that people were suffering in the South.

What would be May's alternative explanation?  Would he say that Roberta had an antecedent disposition that human beings not suffer, but this was not an antecedent desire?  Or would he say that Roberta's moral reasoning about the suffering of the Southern workers created a disposition that humans not suffer that could then produce a desire that these Southern workers should not suffer?

Could this be experimentally tested?  We could test some subjects for the desire that people not suffer.  We could then show them the film about the Southern workers.  We could then see if the desire to relieve the suffering of the Southern workers arises in those subjects who had no antecedent desire that people not suffer.  Of course, we might expect that almost everyone would have some general desire that people not suffer.

If we were to scan their brains during the test, I am not sure that we could distinguish reason and desire clearly enough to resolve the debate between May and Sinhababu.


REFERENCES

Darwall, Stephen. 1983. Impartial Reason. Ithaca, NY: Cornell University Press.

Greene, Joshua. 2013. Moral Tribes: Emotion, Reason, and the Gap Between Us and Them.  New York: Penguin Press.

Haidt, Jonathan. 2012. The Righteous Mind: Why Good People Are Divided by Politics and Religion. New York: Pantheon.

Hume, David. 1888. A Treatise of Human Nature. Ed. L. A. Selby-Bigge. Oxford: Oxford University Press.

Hume, David. 1902. Enquiries Concerning the Human Understanding and Concerning the Principles of Morals. 2nd ed. Oxford: Clarendon Press.

May, Joshua. 2018. Regard for Reason in the Moral Mind. Oxford: Oxford University Press.

Mikhail, John. 2011. Elements of Moral Cognition: Rawls' Linguistic Analogy and the Cognitive Science of Moral and Legal Judgment. New York: Cambridge University Press.

Prinz, Jesse. 2012. Beyond Human Nature: How Culture and Experience Shape the Human Mind. New York: Norton.

Sinhababu, Neil. 2009. "The Humean Theory of Motivation Reformulated and Defended." Philosophical Review 118:465-500.

Peter DeScioli's Response: The Kantian Denial of the Thomistic Distinction Between Intended and Unintended Killing

Peter DeScioli has sent me some responses to my previous post.  He has given me permission to quote them here:

I just skimmed your article and have just one clarification for now: We did not intend to draw on Kant as an explanation or theory of moral judgment. We use "Kantian" in a purely descriptive sense to mean that people's judgments resist utilitarian tradeoffs in dilemmas like the footbridge trolley problem. Our use of "Kantian" is synonymous with "absolutist", "non-consequentialist", "deontological", "taboo" in Tetlock's sense of resisting tradeoffs, and other synonyms in the moral psychology literature. So just as describing moral judgment as "absolutist" does not appeal to something transcendental, we did not intend "Kantian" to do so. Kant is simply an iconic example of rigid moral judgment focused on prohibited actions and resistant to tradeoffs, and similarly we refer to "categorical imperatives" as a descriptive label of moral psychology, rather than as an appeal to Kant's theories. 

Let me also point you to the passage below from DeScioli 2016 which you cited. It illustrates how I use Kantian as a descriptive label for categorical judgments in contrast to utilitarian judgments which I here label as Vulcan, using Spock from Star Trek to represent utilitarian judgments. I argue that humans are "hybrid Vulcan-Kantians," meaning we have both forms of judgment, as seen in the footbridge and switch versions of the trolley problem. Our view is that the Vulcan judgments come from cognitive systems designed for altruism, while Kantian judgments come from cognitive systems for choosing sides. 

DeScioli has said that "Immanuel Kant would argue . . . that when humans face this dilemma, they should not kill one to save five because there is an inviolable moral rule against killing that cannot be broken regardless of the consequences" (Kurzban et al. 2012, 323).  So, DeScioli suggests, in the footbridge version of the trolley problem, most people show a Kantian morality in refusing to kill the fat man because they believe there is an "inviolable moral rule against killing" regardless of the good "intended outcome" (saving five lives) of the killing.  But in the switch version of the trolley problem, most people show a utilitarian morality that justifies killing one person when the "intended outcome" is good--saving five lives.

DeScioli sees an unresolvable contradiction between two kinds of moral rules--killing is always wrong versus killing is wrong except when the "intended outcome" is good.

But as DeScioli has indicated, John Mikhail's research offers a plausible way to resolve this contradiction by seeing the Thomistic Principle of Double Effect as part of the evolutionary moral psychology of human beings.  By seeing that one action can have two effects--one that is intended and another that is foreseen but unintended--we can see that the outcomes or consequences in the footbridge and switch cases of the trolly problem are not the same.  In both cases, one person is killed to save five people.  But in the footbridge case, both the saving of the five people and the killing of one person are intended.  While in the switch case, the saving of the five is intended, but the killing of one is not.

DeScioli recognizes this Thomistic distinction between intended and unintended killing when he considers the laws of violence.  "Thou shalt not kill . . . proclaims the most unanimous and iconic of moral laws" (DeScioli 2023, 202).  Here then is the Kantian categorical imperative--no killing regardless of the consequences.  "But there are of course exceptions," DeScioli says.  We allow killing to punish a wrongdoer, killing in self-defense, and the killing of enemy combatants in war.  But doesn't that deny the Kantian categorical imperative of no killing regardless of the consequences and with no exceptions?

As Aquinas indicated, these exceptions to the no killing rule depend on the distinction between intended and unintended killing.  One may kill an aggressor to save one's life or the lives of others, but only as long as the killing is not the directly intended effect.  If the aggressor retreats or surrenders, and thus gives up the threat to life, we cannot rightly kill him.  To kill him in that situation would be an intended killing, which is wrong.  This requires that we judge the circumstances and the consequences of our actions.

This Thomistic principle of double effect in cases of killing is clearly illustrated in the laws of just war.  Combatants may kill enemy combatants in war to remove their threat to life.  But once the enemy combatants surrender, we cannot kill them without being charged with intentional murder.  We may directly target enemy combatants for attack, but we may not directly target noncombatants, even though noncombatants are often killed as an unintended side-effect of attacks directed at combatants.  So, for example, we can condemn the directly intended terror bombing of Germany and Japan in World War II by the allies as unjust.

This illustrates DeScioli's primary argument "on the origin of laws by natural selection"--that moral rules and laws are for choosing sides in conflicts.  So when someone threatens to kill someone, and his threatened victim argues that this is morally wrong, we can take the side of the victim by agreeing to moral rules or laws that prohibit unjustified killing.  But strangely DeScioli denies that people taking the same side in a conflict is a form of cooperation.  Equally strange is that DeScioli does not see how the rule of justified killing--such as killing in self-defense or killing to save the lives of others--denies the Kantian absolute rule of no killing with no exceptions.

Consider this scenario at the opening of one of his articles:

"Imagine you are alone on a desert island when a hulking man says to hand over your food supplies or he will kill you.  You protest that his threats are morally wrong.  How much protection could your moral judgment really provide?  If you had to choose, would you defend yourself with a hand axe or moral arguments?  Now imagine instead that there are fifty people on the island.  In this case, morality might actually be the better weapon: a persuasive moral argument could rally dozens of armed defenders to your side" (DeScioli 2016, 23).

Persuading dozens of people to give you armed defense against the threats of a murderer sounds like cooperation to me!  Indeed, this is exactly how social cooperation emerges in Locke's state of nature when people agree to formulate the law of nature for resolving conflicts and to punish the violators of that natural law.  Moreover, recruiting "armed defenders to your side" must violate the Kantian absolute rule of no killing--not even in self defense.

I will say more about this in another post.