My Kindle highlights from The Moral Landscape by Sam Harris.

Human well-being entirely depends on events in the world and on states of the human brain. Consequently, there must be scientific truths to be known about it.

The fact that we may not be able to resolve specific moral dilemmas does not suggest that all competing responses to them are equally valid. In my experience, mistaking no answers in practice for no answers in principle is a great source of moral confusion.

Just as there is no such thing as Christian physics or Muslim algebra, we will see that there is no such thing as Christian or Muslim morality. Indeed, I will argue that morality should be considered an undeveloped branch of science.

Knowing what the Creator of the Universe believes about right and wrong inspires religious conservatives to enforce this vision in the public sphere at almost any cost; not knowing what is right—or that anything can ever be truly right—often leads secular liberals to surrender their intellectual standards and political freedoms with both hands.

Meaning, values, morality, and the good life must relate to facts about the well-being of conscious creatures—and, in our case, must lawfully depend upon events in the world and upon states of the human brain. Rational, open-ended, honest inquiry has always been the true source of insight into such processes. Faith, if it is ever right about anything, is right by accident.

I’m not suggesting that we will necessarily discover one right answer to every moral question or a single best way for human beings to live. Some questions may admit of many answers, each more or less equivalent.

To see that multiple answers to moral questions need not pose a problem for us, consider how we currently think about food: no one would argue that there must be one right food to eat. And yet there is still an objective difference between healthy food and poison.

The world’s profusion of foods never tempts us to say that there are no facts to be known about human nutrition or that all culinary styles must be equally healthy in principle.

If there are objective truths to be known about human well-being—if kindness, for instance, is generally more conducive to happiness than cruelty is—then science should one day be able to make very precise claims about which of our behaviors and uses of attention are morally good, which are neutral, and which are worth abandoning.

My goal is to convince you that human knowledge and human values can no longer be kept apart. The world of measurement and the world of meaning must eventually be reconciled. And science and religion—being antithetical ways of thinking about the same reality—will never come to terms. As with all matters of fact, differences of opinion on moral questions merely reveal the incompleteness of our knowledge; they do not oblige us to respect a diversity of views indefinitely.

Hume famously argued that no description of the way the world is (facts) can tell us how we ought to behave (morality).

(1) whatever can be known about maximizing the well-being of conscious creatures—which is, I will argue, the only thing we can reasonably value—must at some point translate into facts about brains and their interaction with the world at large; (2) the very idea of “objective” knowledge (i.e., knowledge acquired through honest observation and reasoning) has values built into it, as every effort we make to discuss facts depends upon principles that we must first value (e.g., logical consistency, reliance on evidence, parsimony, etc.); (3) beliefs about facts and beliefs about values seem to arise from similar processes at the level of the brain: it appears that we have a common system for judging truth and falsity in both domains.

Following Hume, the philosopher G. E. Moore declared that any attempt to locate moral truths in the natural world was to commit a “naturalistic fallacy.”

If we define “good” as that which supports well-being, as I will argue we must, the regress initiated by Moore’s “open question argument” really does stop. While I agree with Moore that it is reasonable to wonder whether maximizing pleasure in any given instance is “good,” it makes no sense at all to ask whether maximizing well-being is “good.” It seems clear that what we are really asking when we wonder whether a certain state of pleasure is “good,” is whether it is conducive to, or obstructive of, some deeper form of well-being. This question is perfectly coherent; it surely has an answer (whether or not we are in a position to answer it); and yet, it keeps notions of goodness anchored to the experience of sentient beings.

[T]he concept of well-being is like the concept of physical health: it resists precise definition, and yet it is indispensable. In fact, the meanings of both terms seem likely to remain perpetually open to revision as we make progress in science.

While the possibilities of human experience must be realized in the brains that evolution has built for us, our brains were not designed with a view to our ultimate fulfillment. Evolution could never have foreseen the wisdom or necessity of creating stable democracies, mitigating climate change, saving other species from extinction, containing the spread of nuclear weapons, or of doing much else that is now crucial to our happiness in this century.

For my argument about the moral landscape to hold, I think one need only grant two points: (1) some people have better lives than others, and (2) these differences relate, in some lawful and not entirely arbitrary way, to states of the human brain and to states of the world.

[T]he moment one grants there is a difference between the Bad Life and the Good Life that lawfully relates to states of the human brain, to human behavior, and to states of the world, one has admitted that there are right and wrong answers to questions of morality.

Anyone who doesn’t see that the Good Life is preferable to the Bad Life is unlikely to have anything to contribute to a discussion about human well-being. Must we really argue that beneficence, trust, creativity, etc., enjoyed in the context of a prosperous civil society are better than the horrors of civil war endured in a steaming jungle filled with aggressive insects carrying dangerous pathogens? I don’t think so.

[T]he mere endurance of a belief system or custom does not suggest that it is adaptive, much less wise. It merely suggests that it hasn’t led directly to a society’s collapse or killed its practitioners outright.

Belief also bridges the gap between facts and values. We form beliefs about facts: and belief in this sense constitutes most of what we know about the world—through science, history, journalism, etc. But we also form beliefs about values: judgments about morality, meaning, personal goals, and life’s larger purpose.

Anyone who wants to understand the world should be open to new facts and new arguments, even on subjects where his or her views are very well established. Similarly, anyone truly interested in morality—in the principles of behavior that allow people to flourish—should be open to new evidence and new arguments that bear upon questions of happiness and suffering. Clearly, the chief enemy of open conversation is dogmatism in all its forms.

The obvious difference between genes and memes (e.g., beliefs, ideas, cultural practices) is also important to keep in view. The latter are communicated; they do not travel with the gametes of their human hosts. The survival of memes, therefore, is not dependent on their conferring some actual benefit (reproductive or otherwise) on individuals or groups. It is quite possible for people to traffic in ideas and other cultural products that diminish their well-being for centuries on end.

Because there are no easy remedies for social inequality, many scientists and public intellectuals also believe that the great masses of humanity are best kept sedated by pious delusions. Many assert that, while they can get along just fine without an imaginary friend, most human beings will always need to believe in God. In my experience, people holding this opinion never seem to notice how condescending, unimaginative, and pessimistic a view it is of the rest of humanity—and of generations to come.

Here is our situation: if the basic claims of religion are true, the scientific worldview is so blinkered and susceptible to supernatural modification as to be rendered nearly ridiculous; if the basic claims of religion are false, most people are profoundly confused about the nature of reality, confounded by irrational hopes and fears, and tending to waste precious time and attention—often with tragic results. Is this really a dichotomy about which science can claim to be neutral?

I am arguing that science can, in principle, help us understand what we should do and should want—and, therefore, what other people should do and should want in order to live the best lives possible. My claim is that there are right and wrong answers to moral questions, just as there are right and wrong answers to questions of physics, and such answers may one day fall within reach of the maturing sciences of mind.

Science simply represents our best effort to understand what is going on in this universe, and the boundary between it and the rest of rational thought cannot always be drawn. There are many tools one must get in hand to think scientifically—ideas about cause and effect, respect for evidence and logical coherence, a dash of curiosity and intellectual honesty, the inclination to make falsifiable predictions, etc.—and these must be put to use long before one starts worrying about mathematical models or specific data.

Once we see that a concern for well-being (defined as deeply and as inclusively as possible) is the only intelligible basis for morality and values, we will see that there must be a science of morality, whether or not we ever succeed in developing it: because the well-being of conscious creatures depends upon how the universe is, altogether.

As the philosopher John Searle once pointed out, there are two very different senses of the terms “objective” and “subjective.” The first sense relates to how we know (i.e., epistemology), the second to what there is to know (i.e., ontology). When we say that we are reasoning or speaking “objectively,” we generally mean that we are free of obvious bias, open to counterarguments, cognizant of the relevant facts, and so on. This is to make a claim about how we are thinking. In this sense, there is no impediment to our studying subjective (i.e., first-person) facts “objectively.”

However, many people seem to think that because moral facts relate to our experience (and are, therefore, ontologically “subjective”), all talk of morality must be “subjective” in the epistemological sense (i.e., biased, merely personal, etc.). This is simply untrue. I hope it is clear that when I speak about “objective” moral truths, or about the “objective” causes of human well-being, I am not denying the necessarily subjective (i.e., experiential) component of the facts under discussion. I am certainly not claiming that moral truths exist independent of the experience of conscious beings—like the Platonic Form of the Good—or that certain actions are intrinsically wrong. I am simply saying that, given that there are facts—real facts—to be known about how conscious creatures can experience the worst possible misery and the greatest possible well-being, it is objectively true to say that there are right and wrong answers to moral questions, whether or not we can always answer these questions in practice.

Another thing that makes the idea of moral truth difficult to discuss is that people often employ a double standard when thinking about consensus: most people take scientific consensus to mean that scientific truths exist, and they consider scientific controversy to be merely a sign that further work remains to be done; and yet many of these same people believe that moral controversy proves that there can be no such thing as moral truth, while moral consensus shows only that human beings often harbor the same biases. Clearly, this double standard rigs the game against a universal conception of morality. The deeper issue, however, is that truth has nothing, in principle, to do with consensus: one person can be right, and everyone else can be wrong. Consensus is a guide to discovering what is going on in the world, but that is all that it is. Its presence or absence in no way constrains what may or may not be true.

All other notions of value will bear some relationship to the actual or potential experience of conscious beings. So my claim that consciousness is the basis of human values and morality is not an arbitrary starting point.

In speaking of “moral truth,” I am saying that there must be facts regarding human and animal well-being about which we can also be ignorant or mistaken. In both cases, science—and rational thought generally—is the tool we can use to uncover these facts.

I think our concern for well-being is even less in need of justification than our concern for health is—as health is merely one of its many facets. And once we begin thinking seriously about human well-being, we will find that science can resolve specific questions about morality and human values, even while our conception of “well-being” evolves.

The person who claims that he does not want to be better off is either wrong about what he does, in fact, want (i.e., he doesn’t know what he’s missing), or he is lying, or he is not making sense. The person who insists that he is committed to treating children with kindness for reasons that have nothing to do with anyone’s well-being is also not making sense.

And, as I have said, there may be many different ways for individuals and communities to thrive—many peaks on the moral landscape—so if there is real diversity in how people can be deeply fulfilled in this life, such diversity can be accounted for and honored in the context of science. The concept of “well-being,” like the concept of “health,” is truly open for revision and discovery. Just how fulfilled is it possible for us to be, personally and collectively? What are the conditions—ranging from changes in the genome to changes in economic systems—that will produce such happiness? We simply do not know.

Even if each conscious being has a unique nadir on the moral landscape, we can still conceive of a state of the universe in which everyone suffers as much as he or she (or it) possibly can. If you think we cannot say this would be “bad,” then I don’t know what you could mean by the word “bad” (and I don’t think you know what you mean by it either).

We simply must stand somewhere. I am arguing that, in the moral sphere, it is safe to begin with the premise that it is good to avoid behaving in such a way as to produce the worst possible misery for everyone. I am not claiming that most of us personally care about the experience of all conscious beings; I am saying that a universe in which all conscious beings suffer the worst possible misery is worse than a universe in which they experience well-being. This is all we need to speak about “moral truth” in the context of science.

Once we admit that the extremes of absolute misery and absolute flourishing—whatever these states amount to for each particular being in the end—are different and dependent on facts about the universe, then we have admitted that there are right and wrong answers to questions of morality.

Imagine if there were only two people living on earth: we can call them Adam and Eve. Clearly, we can ask how these two people might maximize their well-being. Are there wrong answers to this question? Of course. (Wrong answer number 1: smash each other in the face with a large rock.)

Even if there are a thousand different ways for these two people to thrive, there will be many ways for them not to thrive—and the differences between luxuriating on a peak of well-being and languishing in a valley of internecine horror will translate into facts that can be scientifically understood. Why would the difference between right and wrong answers suddenly disappear once we add 6.7 billion more people to this experiment?

The moment we admit that consciousness is the context in which any discussion of values makes sense, we must admit that there are facts to be known about how the experience of conscious creatures can change.

Grounding our values in a continuum of conscious states—one that has the worst possible misery for everyone at its depths and differing degrees of well-being at all other points—seems like the only legitimate context in which to conceive of values and moral norms. Of course, anyone who has an alternative set of moral axioms is free to put them forward, just as they are free to define “science” any way they want.

The fact that it might be difficult to decide exactly how to balance individual rights against collective interests, or that there might be a thousand equivalent ways of doing this, does not mean that there aren’t objectively terrible ways of doing this. The difficulty of getting precise answers to certain moral questions does not mean that we must hesitate to condemn the morality of the Taliban—not just personally, but from the point of view of science. The moment we admit that we know anything about human well-being scientifically, we must admit that certain individuals or cultures can be absolutely wrong about it.

Again, in talking about a science of morality, I am not referring to an evolutionary account of all the cognitive and emotional processes that govern what people do when they say they are being “moral”; I am referring to the totality of scientific facts that govern the range of conscious experiences that are possible for us. To say that there are truths about morality and human values is simply to say that there are facts about well-being that await our discovery—regardless of our evolutionary history. While such facts necessarily relate to the experience of conscious beings, they cannot be the mere invention of any person or culture.

Moral relativism is clearly an attempt to pay intellectual reparations for the crimes of Western colonialism, ethnocentrism, and racism. This is, I think, the only charitable thing to be said about it. I hope it is clear that I am not defending the idiosyncrasies of the West as any more enlightened, in principle, than those of any other culture. Rather, I am arguing that the most basic facts about human flourishing must transcend culture, just as most other facts do.

I happen to believe … changing people’s ethical commitments … is the most important task facing humanity in the twenty-first century. Nearly every other important goal—from combating climate change, to fighting terrorism, to curing cancer, to saving the whales—falls within its purview. Of course, moral persuasion is a difficult business, but it strikes me as especially difficult if we haven’t figured out in what sense moral truths exist.

The framework of a moral landscape guarantees that many people will have flawed conceptions of morality, just as many people have flawed conceptions of physics. Some people think “physics” includes (or validates) practices like astrology, voodoo, and homeopathy. These people are, by all appearances, simply wrong about physics.

In the United States, a majority of people (57 percent) believe that preventing homosexuals from marrying is a “moral” imperative. However, if this belief rests on a flawed sense of how we can maximize our well-being, such people may simply be wrong about morality. And the fact that millions of people use the term “morality” as a synonym for religious dogmatism, racism, sexism, or other failures of insight and compassion should not oblige us to merely accept their terminology until the end of time.

As we better understand the brain, we will increasingly understand all of the forces—kindness, reciprocity, trust, openness to argument, respect for evidence, intuitions of fairness, impulse control, the mitigation of aggression, etc.—that allow friends and strangers to collaborate successfully on the common projects of civilization. Understanding ourselves in this way, and using this knowledge to improve human life, will be among the most important challenges to science in the decades to come.

Certain biological traits appear to have been shaped by, and to have further enhanced, the human capacity for cooperation. For instance, unlike the rest of the earth’s creatures, including our fellow primates, the sclera of our eyes (the region surrounding the colored iris) is white and exposed. This makes the direction of the human gaze very easy to detect, allowing us to notice even the subtlest shifts in one another’s visual attention.

The moment one begins thinking about morality in terms of well-being, it becomes remarkably easy to discern a moral hierarchy across human societies.

I believe that we will increasingly understand good and evil, right and wrong, in scientific terms, because moral concerns translate into facts about how our thoughts and behaviors affect the well-being of conscious creatures like ourselves. If there are facts to be known about the well-being of such creatures—and there are—then there must be right and wrong answers to moral questions. Students of philosophy will notice that this commits me to some form of moral realism (viz. moral claims can really be true or false) and some form of consequentialism (viz. the rightness of an act depends on how it impacts the well-being of conscious creatures). While moral realism and consequentialism have both come under pressure in philosophical circles, they have the virtue of corresponding to many of our intuitions about how the world works.

Here is my (consequentialist) starting point: all questions of value (right and wrong, good and evil, etc.) depend upon the possibility of experiencing such value. Without potential consequences at the level of experience—happiness, suffering, joy, despair, etc.—all talk of value is empty. Therefore, to say that an act is morally necessary, or evil, or blameless, is to make (tacit) claims about its consequences in the lives of conscious creatures (whether actual or potential).

Moral view A is truer than moral view B, if A entails a more accurate understanding of the connections between human thoughts/intentions/behavior and human well-being.

Total uniformity in the moral sphere—either interpersonally or intrapersonally—may be hopeless. So what? This is precisely the lack of closure we face in all areas of human knowledge. Full consensus as a scientific goal only exists in the limit, at a hypothetical end of inquiry. Why not tolerate the same open-endedness in our thinking about human well-being?

[T]he moment we accept that there are right and wrong answers to questions of human well-being, we must admit that many people are simply wrong about morality.

Most scientists seem to believe that no matter how maladaptive or masochistic a person’s moral commitments, it is impossible to say that he is ever mistaken about what constitutes a good life.

One of the problems with consequentialism in practice is that we cannot always determine whether the effects of an action will be bad or good. In fact, it can be surprisingly difficult to decide this even in retrospect.

One difficulty we face in determining the moral valence of an event is that it often seems impossible to determine whose well-being should most concern us. People have competing interests, mutually incompatible notions of happiness, and there are many well-known paradoxes that leap into our path the moment we begin thinking about the welfare of whole populations.

Slovic’s experimental work suggests that we intuitively care most about a single, identifiable human life, less about two, and we grow more callous as the body count rises. Slovic believes that this “psychic numbing” explains the widely lamented fact that we are generally more distressed by the suffering of single child (or even a single animal) than by a proper genocide. What Slovic has termed “genocide neglect”—our reliable failure to respond, both practically and emotionally, to the most horrific instances of unnecessary human suffering—represents one of the more perplexing and consequential failures of our moral intuition.

Clearly, this proves that we cannot rely on a simple summation or averaging of welfare as our only metric. And yet, at the extremes, we can see that human welfare must aggregate in some way: it really is better for all of us to be deeply fulfilled than it is for everyone to live in absolute agony.

And what about remaining partial to one’s friends and family? Is it wrong for me to save the life of my only child if, in the process, I neglect to save a stranger’s brood of eight? Wrestling with such questions has convinced many people that morality does not obey the simple laws of arithmetic. However, such puzzles merely suggest that certain moral questions could be difficult or impossible to answer in practice; they do not suggest that morality depends upon something other than the consequences of our actions and intentions.

This is where a science of morality could be indispensable to us: the more we understand the causes and constituents of human fulfillment, and the more we know about the experiences of our fellow human beings, the more we will be able to make intelligent decisions about which social policies to adopt.

[C]onsequentialism is less a method of answering moral questions than it is a claim about the status of moral truth. Our assessment of consequences in the moral domain must proceed as it does in all others: under the shadow of uncertainty, guided by theory, data, and honest conversation. The fact that it may often be difficult, or even impossible, to know what the consequences of our thoughts and actions will be does not mean that there is some other basis for human values that is worth worrying about.

[P]erhaps there are two possible worlds that maximize the well-being of their inhabitants to precisely the same degree: in world X everyone is focused on the welfare of all others without bias, while in world Y everyone shows some degree of moral preference for their friends and family. Perhaps these worlds are equally good, in that their inhabitants enjoy precisely the same level of well-being. These could be thought of as two peaks on the moral landscape. Perhaps there are others. Does this pose a threat to moral realism or to consequentialism? No, because there would still be right and wrong ways to move from our current position on the moral landscape toward one peak or the other,

It seems to me that we already know enough about the human condition to know that killing cartoonists for blasphemy does not lead anywhere worth going on the moral landscape.

[T]o say that there are right answers to questions of how to maximize human well-being is not to say that we will always be in a position to answer such questions. There will be peaks and valleys on the moral landscape, and movement between them is clearly possible, whether or not we always know which way is up.

In his book A Theory of Justice Rawls offered an approach to building a fair society that he considered an alternative to the aim of maximizing human welfare … how reasonable people would structure a society, guided by their self-interest, if they couldn’t know what sort of person they would be in it. Rawls called this novel starting point “the original position,”… In other words, we can design any society we like as long as we do not presume to know, in advance, whether we will be black or white, male or female, young or old, healthy or sick, of high or low intelligence, beautiful or ugly, etc.

While each individual’s search for happiness may not be compatible in every instance with our efforts to build a just society, we should not lose sight of the fact that societies do not suffer; people do. The only thing wrong with injustice is that it is, on some level, actually or potentially bad for people.

While there may be some surprises in store for us down this path, there is every reason to expect that kindness, compassion, fairness, and other classically “good” traits will be vindicated neuroscientifically—which is to say that we will only discover further reasons to believe that they are good for us, in that they generally enhance our lives.

Who ever said that being truly good, or even ethically consistent, must be easy? I have no doubt that I am less good than I could be. Which is to say, I am not living in a way that truly maximizes the well-being of others. I am nearly as sure, however, that I am also failing to live in a way that maximizes my own well-being. This is one of the paradoxes of human psychology: we often fail to do what we ostensibly want to do and what is most in our self-interest to do. We often fail to do what we most want to do—or, at the very least, we fail to do what, at the end of the day (or year, or lifetime) we will most wish we had done.

We cannot perfectly measure or reconcile the competing needs of billions of creatures. We often cannot effectively prioritize our own competing needs. What we can do is try, within practical limits, to follow a path that seems likely to maximize both our own well-being and the well-being of others. This is what it means to live wisely and ethically.

[S]cientists like Joshua Greene and Jonathan Haidt seem to think that the very existence of moral controversy nullifies the possibility of moral truth. In their opinion, all we can do is study what human beings do in the name of “morality.” Thus, if religious conservatives find the prospect of gay marriage abhorrent, and secular liberals find it perfectly acceptable, we are confronted by a mere difference of moral preference—not a difference that relates to any deeper truths about human life.

Haidt is right to notice that the brain’s emotional circuitry often governs our moral intuitions, and the way in which feeling drives judgment is surely worthy of study. But it does not follow that there are no right and wrong answers to questions of morality. Just as people are often less than rational when claiming to be rational, they can be less than moral when claiming to be moral.

What, after all, is the problem with desecrating a copy of the Qur’an? There would be no problem but for the fact that people believe that the Qur’an is a divinely authored text. Such people almost surely believe that some harm could come to them or to their tribe as a result of such sacrileges—if not in this world, then in the next … Whatever interpretation one favors, sacredness and respect for religious authority seem to reduce to a concern about harm just the same.

While anxiety and fear are emotions that most of us would prefer to live without, they serve as anchors to social and moral norms. Without an ability to feel anxious about one’s own transgressions, real or imagined, norms become nothing more than “rules that others make up.” The developmental literature also supports this interpretation: fearful children have been shown to display greater moral understanding. It remains an open question, therefore, just how free of anxiety we can reasonably want to be. Again, this is something that only an empirical science of morality could decide. And as more effective remedies for anxiety appear on the horizon, this is an issue that we will have to confront in some form.

While it may be difficult to accept, the research strongly suggests that some people cannot learn to care about others. Perhaps we will one day develop interventions to change this. For the purposes of this discussion, however, it seems sufficient to point out that we are beginning to understand the kinds of brain pathologies that lead to the most extreme forms of human evil. And just as some people have obvious moral deficits, others must possess moral talent, moral expertise, and even moral genius. As with any human ability, these gradations must be expressed at the level of the brain.

We must continually remind ourselves that there is a difference between what is natural and what is actually good for us. Cancer is perfectly natural, and yet its eradication is a primary goal of modern medicine. Evolution may have selected for territorial violence, rape, and other patently unethical behaviors as strategies to propagate one’s genes—but our collective well-being clearly depends on our opposing such natural tendencies.

[H]uman goodness and human evil are the product of natural events. The great worry is that any honest discussion of the underlying causes of human behavior seems to erode the notion of moral responsibility. If we view people as neuronal weather patterns, how can we coherently speak about morality? And if we remain committed to seeing people as people, some who can be reasoned with and some who cannot, it seems that we must find some notion of personal responsibility that fits the facts.

If a person’s actions seem to have been entirely out of character, this will influence our sense of the risk he now poses to others. If the accused appears unrepentant and anxious to kill again, we need entertain no notions of free will to consider him a danger to society.

The men and women on death row have some combination of bad genes, bad parents, bad ideas, and bad luck—which of these quantities, exactly, were they responsible for? No human being stands as author to his own genes or his upbringing, and yet we have every reason to believe that these factors determine his character throughout life. Our system of justice should reflect our understanding that each of us could have been dealt a very different hand in life. In fact, it seems immoral not to recognize just how much luck is involved in morality itself.

Despite our attachment to notions of free will, most of us know that disorders of the brain can trump the best intentions of the mind. This shift in understanding represents progress toward a deeper, more consistent, and more compassionate view of our common humanity—and we should note that this is progress away from religious metaphysics. It seems to me that few concepts have offered greater scope for human cruelty than the idea of an immortal soul that stands independent of all material influences, ranging from genes to economic systems.

Could thinking about the mind as the product of the physical brain diminish our compassion for one another? While it is reasonable to ask this question, it seems to me that, on balance, soul/body dualism has been the enemy of compassion. For instance, the moral stigma that still surrounds disorders of mood and cognition seems largely the result of viewing the mind as distinct from the brain. When the pancreas fails to produce insulin, there is no shame in taking synthetic insulin to compensate for its lost function. Many people do not feel the same way about regulating mood with antidepressants (for reasons that appear quite distinct from any concern about potential side effects). If this bias has diminished in recent years, it has been because of an increased appreciation of the brain as a physical organ.

While we often make a conventional distinction between “belief” and “knowledge,” these categories are actually quite misleading. Knowing that George Washington was the first president of the United States and believing the statement “George Washington was the first president of the United States” amount to the same thing. When we distinguish between belief and knowledge in ordinary conversation, it is generally for the purpose of drawing attention to degrees of certainty: I’m apt to say “I know it” when I am quite certain that one of my beliefs about the world is true; when I’m less sure, I may say something like “I believe it is probably true.” Most of our knowledge about the world falls between these extremes. The entire spectrum of such convictions—ranging from better-than-a-coin-toss to I-would-bet-my-life-on-it—expresses gradations of “belief.”

[E]verything we know outside of our personal experience is the result of our having encountered specific linguistic propositions—the sun is a star; Julius Caesar was a Roman general; broccoli is good for you—and found no reason (or means) to doubt them.

When we believe a proposition to be true, it is as though we have taken it in hand as part of our extended self: we are saying, in effect, “This is mine. I can use this. This fits my view of the world.” It seems to me that such cognitive acceptance has a distinctly positive emotional valence. We actually like the truth, and we may, in fact, dislike falsehood.

I have argued that there is no gulf between facts and values, because values reduce to a certain type of fact. This is a philosophical claim, and as such, I can make it before ever venturing into the lab. However, my research on belief suggests that the split between facts and values should look suspicious: First, belief appears to be largely mediated by the MPFC, which seems to already constitute an anatomical bridge between reasoning and value. Second, the MPFC appears to be similarly engaged, irrespective of a belief’s content. This finding of content-independence challenges the fact/value distinction very directly: for if, from the point of view of the brain, believing “the sun is a star” is importantly similar to believing “cruelty is wrong,” how can we say that scientific and ethical judgments have nothing in common?

Two people can hold the same belief for very different reasons, and such differences generally matter. In the year 2003, it was one thing to believe that the United States should not invade Iraq because the ongoing war in Afghanistan was more important; it was another to believe it because you think it is an abomination for infidels to trespass on Muslim land. Knowing what a person believes on a specific subject is not identical to knowing how that person thinks.

Reasoning errors aside, we know that people often acquire their beliefs about the world for reasons that are more emotional and social than strictly cognitive. Wishful thinking, self-serving bias, in-group loyalties, and frank self-deception can lead to monstrous departures from the norms of rationality. Most beliefs are evaluated against a background of other beliefs and often in the context of an ideology that a person shares with others. Consequently, people are rarely as open to revising their views as reason would seem to dictate.

In a recent study of moral reasoning, subjects were asked to judge whether it was morally correct to sacrifice the life of one person to save one hundred, while being given subtle clues as to the races of the people involved. Conservatives proved less biased by race than liberals and, therefore, more even-handed. Liberals, as it turns out, were very eager to sacrifice a white person to save one hundred nonwhites, but not the other way around—all the while maintaining that considerations of race had not entered into their thinking.

If believing a mathematical equation (vs. disbelieving another) and believing an ethical proposition (vs. disbelieving another) produce the same changes in neurophysiology, the boundary between scientific dispassion and judgments of value becomes difficult to establish.

Chris Frith, a pioneer in the use of functional neuroimaging, recently wrote: [W]here does conscious reasoning come into the picture? It is an attempt to justify the choice after it has been made. And it is, after all, the only way we have to try to explain to other people why we made a particular decision. But given our lack of access to the brain processes involved, our justification is often spurious: a post-hoc rationalization, or even a confabulation—a “story” born of the confusion between imagination and memory.

The fact that we are unaware of most of what goes on in our brains does not render the distinction between having good reasons for what one believes and having bad ones any less clear or consequential. Nor does it suggest that internal consistency, openness to information, self-criticism, and other cognitive virtues are less valuable than we generally assume.

There is no question that human beings regularly fail to achieve the norms of rationality. But we do not merely fail—we fail reliably. We can, in other words, use reason to understand, quantify, and predict our violations of its norms. This has moral implications. We know, for instance, that the choice to undergo a risky medical procedure will be heavily influenced by whether its possible outcomes are framed in terms of survival rates or mortality rates. We know, in fact, that this framing effect is no less pronounced among doctors than among patients. Given this knowledge, physicians have a moral obligation to handle medical statistics in ways that minimize unconscious bias. Otherwise, they cannot help but inadvertently manipulate both their patients and one another, guaranteeing that some of the most important decisions in life will be unprincipled.

Science has long been in the values business. Despite a widespread belief to the contrary, scientific validity is not the result of scientists abstaining from making value judgments; rather, scientific validity is the result of scientists making their best effort to value principles of reasoning that link their beliefs to reality, through reliable chains of evidence and argument. This is how norms of rational thought are made effective.

To say that judgments of truth and goodness both invoke specific norms seems another way of saying that they are both matters of cognition, as opposed to mere sentiment. That is why one cannot defend one’s factual or moral position by reference to one’s preferences. One cannot say that water is H2O or that lying is wrong simply because one wants to think this way. To defend such propositions, one must invoke a deeper principle. To believe that X is true or that Y is ethical is also to believe others should share these beliefs under similar circumstances.

The answer to the question “What should I believe, and why should I believe it?” is generally a scientific one. Believe a proposition because it is well supported by theory and evidence; believe it because it has been experimentally verified; believe it because a generation of smart people have tried their best to falsify it and failed; believe it because it is true (or seems so). This is a norm of cognition as well as the core of any scientific mission statement. As far as our understanding of the world is concerned—there are no facts without values.

Human beings may be genetically predisposed to superstition: for natural selection should favor rampant belief formation as long as the benefits of the occasional, correct belief are great enough.

We may also be what the psychologist Paul Bloom has called “common sense dualists”—that is, we may be naturally inclined to see the mind as distinct from the body and, therefore, we tend to intuit the existence of disembodied minds at work in the world.

However predisposed the human mind may be to harboring religious beliefs, it remains a fact that each new generation receives a religious worldview, at least in part, in the form of linguistic propositions—far more so in some societies than in others. Whatever the evolutionary underpinnings of religion, it seems extraordinarily unlikely that there is a genetic explanation for the fact that the French, Swedes, and Japanese tend not to believe in God while Americans, Saudis, and Somalis do. Clearly, religion is largely a matter of what people teach their children to believe about the nature of reality.

Despite vast differences in the underlying processing responsible for religious and nonreligious modes of thought, the distinction between believing and disbelieving a proposition appears to transcend content. Our research suggests that these opposing states of mind can be detected by current techniques of neuroimaging and are intimately tied to networks involved in self-representation and reward. These findings may have many areas of application—ranging from the neuropsychology of religion, to the use of “belief detection” as a surrogate for “lie detection,” to understanding how the practice of science itself, and truth claims generally, emerge from the biology of the human brain. And again, results of this kind further suggest that a sharp boundary between facts and values does not exist as a matter of human cognition.

While the ultimate relationship between consciousness and matter has not been settled, any naïve conception of a soul can now be jettisoned on account of the mind’s obvious dependency upon the brain. The idea that there might be an immortal soul capable of reasoning, feeling love, remembering life events, etc., all the while being metaphysically independent of the brain, seems untenable given that damage to the relevant neural circuits obliterates these capacities in a living person.

Does the soul of a person suffering from total aphasia (loss of language ability) still speak and think fluently? This is rather like asking whether the soul of a diabetic produces abundant insulin. The specific character of the mind’s dependency on the brain also suggests that there cannot be a unified self at work in each of us. There are simply too many separable components to the human mind—each susceptible to independent disruption—for there to be a single entity to stand as rider to the horse.

As I have argued throughout this book, understanding human well-being at the level of the brain might very well offer some answers to the most pressing questions of human existence—questions like, Why do we suffer? How can we achieve the deepest forms of happiness? Or, indeed, Is it possible to love one’s neighbor as oneself? And wouldn’t any effort to explain human nature without reference to a soul, and to explain morality without reference to God, constitute “atheistic materialism”? Is it really wise to entrust the future of biomedical research in the United States to a man who believes that understanding ourselves through science is impossible, while our resurrection from death is inevitable?

Despite our perennial bad behavior, our moral progress seems to me unmistakable. Our powers of empathy are clearly growing. Today, we are surely more likely to act for the benefit of humanity as a whole than at any point in the past. Of course, the twentieth century delivered some unprecedented horrors. But those of us who live in the developed world are becoming increasingly disturbed by our capacity to do one another harm. We are less tolerant of “collateral damage” in times of war—undoubtedly because we now see images of it—and we are less comfortable with ideologies that demonize whole populations, justifying their abuse or outright destruction.

We will embarrass our descendants, just as our ancestors embarrass us. This is moral progress.

Most scientists treat facts and values as though they were distinct and irreconcilable in principle. I have argued that they cannot be, as anything of value must be valuable to someone (whether actually or potentially)—and, therefore, its value should be attributable to facts about the well-being of conscious creatures. One could call this a “philosophical” position, but it is one that directly relates to the boundaries of science.

Much of the skepticism I encounter when speaking about these issues comes from people who think “happiness” is a superficial state of mind and that there are far more important things in life than “being happy.” Some readers may think that concepts like “well-being” and “flourishing” are similarly effete. However, I don’t know of any better terms with which to signify the most positive states of being to which we can aspire. One of the virtues of thinking about a moral landscape, the heights of which remain to be discovered, is that it frees us from these semantic difficulties. Generally speaking, we need only worry about what it will mean to move “up” as opposed to “down.”

Some of what psychologists have learned about human well-being confirms what everyone already knows: people tend to be happier if they have good friends, basic control over their lives, and enough money to meet their needs. Loneliness, helplessness, and poverty are not recommended. We did not need science to tell us this.

But the best of this research also reveals that our intuitions about happiness are often quite wrong. For instance, most of us feel that having more choices available to us—when seeking a mate, choosing a career, shopping for a new stove, etc.—is always desirable. But while having some choice is generally good, it seems that having too many options tends to undermine our feelings of satisfaction, no matter which option we choose. Knowing this, it could be rational to strategically limit one’s choices. Anyone who has ever remodeled a home will know the glassy-eyed anguish of having gone to one too many stores in search of the perfect faucet.

Clearly, if there is a more important source of value that has nothing to do with the well-being of conscious creatures (in this life or a life to come), my thesis would be disproved. As I have said, however, I cannot conceive of what such a source of value could be: for if someone claimed to have found it somewhere, it could be of no possible interest to anyone, by definition.

If our well-being depends upon the interaction between events in our brains and events in the world, and there are better and worse ways to secure it, then some cultures will tend to produce lives that are more worth living than others;

Whether or not we ever understand meaning, morality, and values in practice, I have attempted to show that there must be something to know about them in principle. And I am convinced that merely admitting this will transform the way we think about human happiness and the public good.

To summarize my central thesis: Morality and values depend on the existence of conscious minds—and specifically on the fact that such minds can experience various forms of well-being and suffering in this universe. Conscious minds and their states are natural phenomena, of course, fully constrained by the laws of Nature (whatever these turn out to be in the end). Therefore, there must be right and wrong answers to questions of morality and values that potentially fall within the purview of science. On this view, some people and cultures will be right (to a greater or lesser degree), and some will be wrong, with respect to what they deem important in life.

In my view, morality must be viewed in the context of our growing scientific understanding of the mind. If there are truths to be known about the mind, there will be truths to be known about how minds flourish; consequently, there will be truths to be known about good and evil.

The purpose of the book is to show that a science of morality, predicated on the value of well-being, would be on no weaker footing than physics, chemistry, medicine, or any other branch of science that must rely on similar, axiomatic assumptions. By analogy to the rest of science, I have argued that the value of avoiding the worst possible misery for everyone can be presupposed—and upon this axiom we can build a science of morality that can then determine (yes, “determine”) myriad other human values.

Will we ever have a completed science of human flourishing? Probably not. Does this mean that there isn’t a right way to maintain compassion while seeking bureaucratic efficiency (or several right ways)? Does the extraordinary complexity of human life prevent us from seeing, at a glance, that certain societies have got the balance between compassion and efficiency entirely wrong? No. (See: Germany, Nazi).

I’m not simply claiming that morality is “fully determined by an objective reality, independent of people’s actual values and desires.” I am claiming that people’s actual values and desires are fully determined by an objective reality, and that we can conceptually get behind all of this—indeed, we must—in order to talk about what is actually good.