Psychopaths are fascinating, in a repugnant sort of way. Whether we read about Ted Bundy or Paul Bernardo or see psychopaths depicted in fictional characters such as Hannibal Lecter, we are forced to wonder how a human being could ever do such horrible things. We are also forced to wonder whether we ourselves could ever do those things - whether such darkness possibly exists deep within us all.

As a sensitive human being, I was always baffled by psychopaths until I studied the topic of psychopathy, especially as understood by its foremost expert, Robert Hare, the psychiatrist who developed the Psychopathy Checklist, now the standard tool for diagnosing people with psychopathy. But it was as a philosopher that I experienced a kind of awakening. This is because I not only came to understand what makes psychopaths tick, but I began to see the wider significance of psychopaths - connections with areas of inquiry that experts such as Hare (let alone philosophers) did not seem to see. (I am a "What is x ?" philosopher, the kind who takes science seriously, the kind who believes that it is not wisdom to ignore evidence.)

In this article, I shall focus on three areas of wider significance: postmodernism, morality, and theology. It is perhaps astonishing that the human phenomenon of psychopathy can teach us anything about these three fields, but as we shall see, it actually has a lot to teach us.

First we need to be reasonably clear on what psychopathy is. Following the work of Hare in his must-read Without Conscience (1995), psychopathy is not a form of insanity or even a mental illness, given the clinical meanings of these terms. Nor need psychopaths be lacking in rationality. Conceivably a psychopath could have the genius of an Einstein and function quite well in the world. There is no twisted logic necessarily involved with psychopathy, no warped thinking that is so obvious in the mentally ill and insane, no hallucinations, no depression, no dysfunctionality necessarily.

Psychopaths are defined in terms of something else - a cluster of features, most of which are deficiencies. This means that psychopathy is a matter of degree. Many of us might score relatively high in one or more of these defining characteristics, but that does not necessarily mean that we are psychopaths. On the other hand, there are those who score so high on the Psychopathy Checklist that they are considered full-fledged psychopaths. They are, so to speak, the interesting ones.

And they are more common than one might think. According to Hare, roughly one in every one hundred humans is a full-fledged psychopath. Imagine that. There you are in a lecture hall with a class of roughly 240 students, and in that room there are probably two or three full-fledged psychopaths.

What distinguishes psychopaths from normal people? Principally, it is a total absence of what we typically take to be moral qualities: sympathy, empathy, compassion, guilt, remorse, conscience, loyalty, truth telling, and a sense of fairness. This also shows up in their brains, for example in EEG experiments. When shown the word car and then the word stab, most people have different emotional and physiological responses to these words that register in their brain waves. The limbic system, which is responsible for people's emotions, exhibits an emotional response to the word stab that is missing (or is very different) when responding to the word car. But for psychopaths there is no difference. Their response is the same. And this is not confined to words. They register no emotional response when they see a person bleeding and screaming in pain or a dead body mangled from a car accident. And it is no different if they are the cause of the screaming person or the mangled dead body.

Psychopaths are also highly narcissistic. Not only are they extremely self-centered, but they also think of themselves as being of a higher nature than the rest of us. To them, normal individuals are made weak by sympathy and empathy and refrain from getting the most that they can from life because of conscience, guilt, and remorse. To psychopaths, we are like sheep. They, on the other hand, are like wolves - animals of prey. The sheep exist for the sake of the wolves. The sheep are to be manipulated, used, and even killed if the situation is right. All that matters is that the wolf be gratified.

In The Descent of Man (1871), Darwin called the human who lacks sympathy, empathy, and other moral instincts an "unnatural monster," but there actually is nothing unnatural about psychopaths, any more than congenital blindness or a very high IQ is unnatural. Hare suspects that in addition to environmental causes, psychopathy may also have genetic ones. But in spite of the role of environmental factors in the expression of our moral instincts, I would think that full-blown psychopathy is primarily genetic. This is because family background does not seem to matter, psychopathy shows up very early in life, psychopaths cannot be rehabilitated, and psychopathy is far more common among males. Interestingly, sympathy and empathy are generally greater in females and appear much earlier in female infancy. In addition, males tend to shut off sympathy and empathy in competitive situations (see The Oxford Handbook of Evolutionary Psychology, 2007). What we seem to have with psychopathy, then, is a statistical phenomenon in evolutionary terms.

Still, how is all of this relevant to philosophy? Let us begin with a standard field in philosophy: epistemology, the study (logos) of knowledge (episteme). A modern challenge to those who believe in the existence of knowledge is known as postmodernism. According to postmodernists, there is no real distinction between truth and falsity, objectivity and subjectivity, fact and theory, knowledge and opinion. For postmodernists, what is called "knowledge" is really merely a powerful opinion, a strong point of view, or a social construction - a prevalent point of view conditioned by social, cultural, and political forces, all of which are sea changes.

As far as I can tell, postmodernism began reasonably enough, in the field of abstract art. Throw some shit against the wall and put a frame around it. Is it art? You have your opinion and I have mine. Neither of us is right or wrong. And if we both agree that it is art, then what is the meaning of it? Again, you have your opinion and I have mine and neither of us is right or wrong. What matters is only that we be allowed to express our opinions.

This perfectly reasonable approach to abstract art then spread to literary theory, and it kept spreading - to the humanities, including philosophy, and the social sciences, particularly sociology and anthropology. Reinforced by cultural relativism, multiculturalism, political correctness, and a left-wing hatred of all that is powerful and mighty (and that means primarily the United States, the military and police, and the natural sciences), postmodernism has now become an imposing dogma in the academic world, provoking physicist Alan Sokal in 1996 to write a postmodernist critique of science that was published in the leading journal for postmodernist critiques of science, Social Text. The editors were duped; the article was bullshit, written in the style of postmodernist writings, using postmodernist jargon and references. It was a beautiful piece of gibberish in the service of an exposé (see Jean Bricmont, "Exposing the Emperor's New Clothes," Free Inquiry, Fall 1998).

But still, what has this to do with psychopaths? For a start, psychopaths lack what may be called "moral virtues and values." I have already listed some of these: sympathy, empathy, conscience, guilt, remorse, a sense of fairness. Psychopaths don't have these, and moreover they don't want them. They don't want them because they see nothing wrong with themselves. They look at the moral virtues and values of normal humans as the very features that make those humans weaklings and suckers, ready to be exploited by people like them. Psychopaths are not like Nietzsche's Overman, who goes beyond good and evil into a new synthesis of the master and slave moralities. Psychopaths, instead, are without morality altogether, and they want to stay that way.

There is a strong analogy here with postmodernism. Just as psychopaths lack moral virtues and values and do not want them, postmodernists lack epistemic virtues and values and do not want them. There is a trend in philosophy of science, in trying to distinguish science from pseudoscience and nonscience, which is not to look for any one or few essentialistic features but to find the distinction in a cluster-class of epistemic virtues and values that promote the pursuit of knowledge. Among these are being clear, valuing evidence, exposing theories to testing, not being dogmatic, keeping explanations and explanatory entities as simple as possible, and not letting politics determine good scholarship. This is why no religion or theology is a science and why astrology and homeopathy are not real sciences either. They lack epistemic virtues and values. And postmodernists lack them too. They lack them, and moreover they don't want them. In fact, in analogy with the narcissism of psychopaths, postmodernists view themselves as superior to those who possess epistemic virtues and values. They see themselves as above such things, as superior. "You don't really think that people believe because of arguments, do you?" is a common question put by postmodernists, usually with an arrogant and condescending tone.

The analogy breaks down when it comes to numbers. Psychopaths number roughly 1 percent of the human population, higher in prisons (not all killers are psychopaths, but many are) and also in corporations, where the attributes of psychopaths (ruthless greed without conscience) are highly valued (see Babiak and Hare, Snakes in Suits, 2006). Postmodernists, on the other hand, probably number far less than 1 percent in the general public as a whole but number considerably higher in universities and colleges among faculty, depending on the division - virtually zero in the natural sciences but upwards of 50 percent or more in the humanities, the social sciences, and philosophy, depending on the department.

The bottom line is that there is no point arguing with postmodernists about why they should pursue knowledge. This is because they lack and do not want the very stuff of knowledge, the epistemic virtues and values. In other words, arguing against them is a colossal waste of time. The most one can hope to achieve is detection. I can pretty much tell when I've come across a postmodernist by his or her reaction to the mention of science or the importance of evidence. I don't hate postmodernists. I'm just not going to waste my time arguing with them; there is no point.

Harry Frankfurt seems to miss this implication in his book On Truth (2006), in which he seems to argue against postmodernists. Frankfurt's argument can only hope to work on those who are not postmodernists. Only they will nod in approval. Instead, the most one can hope to do is to expose postmodernists and what postmodernism is, just as Hare exposed the nature of psychopaths. Once we know what postmodernism is, then we can know how to detect postmodernists and how best to deal with them.

This brings us to our next area in philosophy: morality. What can psychopaths possibly teach us about morality? A lot. Once one realizes what psychopaths are, that they are not necessarily mentally ill or insane but do have a complete absence of moral virtues and values, and once one realizes that a psychopath can be the most intelligent and rational human on the planet, then it ought to become evident that one cannot possibly hope to convince a psychopath of why he should be moral, and it is important to see why.

Throughout the history of moral philosophy, a central question has always been, "Why should I be moral?" Plato and Aristotle attempted to answer the question in terms of individual happiness. An immoral soul, said Plato, is a disordered soul, and a disordered soul cannot achieve happiness because it is not in control of itself. But there is no reason a psychopath could not have his reason rule his emotions and together with his emotions (the spirited part) rule his appetites and still be a psychopath, exploiting humans when possible, taking rational steps to avoid being caught, and having no bad conscience about it.

Aristotle claimed that only the virtuous human can possibly be happy, where moral virtue is a kind of excellence, vice is an excess or deficiency in a moral virtue, and the list of moral virtues is species-specific, a matter of human nature. But a psychopath is not going to be convinced by this argument either, since the nature of a psychopath does not conform to what Aristotle thought the essence of the human species to be.

Bentham and Mill thought we should seek the greatest happiness of the greatest number, because we seek our own happiness and avoid our own pain. But there is no logically compelling reason that will convince a rational and logical psychopath that he should pursue the greatest happiness of the greatest number of people or sentient beings. Such a person can be compelled to pursue his own greatest happiness and the happiness of others only as a means to achieving his own happiness.

Kant thought we should be moral - for example, never treating a person merely as a thing - because that is the rational thing to do. Take any personal maxim of action, he said, and universalize it. Ask, "What if everyone did it?," and if the answer involves you in a self-contradiction, then any motive based on that maxim is immoral. But there is no logically compelling reason that a psychopath should universalize any of his personal maxims of action, and hence, there is no logically compelling reason that he should be moral in Kant's sense of the term.

The upshot is that it is impossible to provide a logically compelling argument to a psychopath for why he should be moral because psychopaths lack the very stuff of morality (sympathy, empathy, conscience, and so on). One can give the psychopath a strong argument for why he should pretend to be moral, but that is a very different thing. In line with the primatologist Frans de Waal (for example, in his The Age of Empathy [2009]), morality is not a veneer but something deep in human nature, the building blocks of which are shared with other primates and relatively intelligent social animals. To the question, then, "Why should I be moral?," the only answer can be, "Because I am a human being," or rather, "Because I am a normal human being." It's like asking a bird why it should fly. The answer can only be, "Because I am a bird." If we take evolution seriously, there can be no other answer.

This brings us to theology, because many with a theological bent will take exception to the view that "taking evolution seriously" means thinking in such purely naturalistic terms as random mutation, natural selection, and other physical processes such as genetic drift and environmental change. The mixture of evolutionary biology with theology is known as theistic evolution, of which there are various kinds. What all the kinds share, however, is a problem known as the "problem of evil": If God exists and is all knowing, all powerful, and all loving, then evil should not exist (evil in the sense of man-made evil, such as murder, and natural evil, such as hurricanes and polio). But evil does exist. So either God does not exist or God does exist but is not all knowing, all powerful, or all loving.

Some, following St. Augustine, have tried to avoid the conclusion by arguing that evil does not exist. Imagine someone telling that to a person dying painfully of cancer, or to a person whose child burned to death in a house fire, or to the thousands who died in the Haiti earthquakes, or to the tens of millions who died in Nazi and communist concentration camps.

Others, following St. Irenaeus, accept that evil exists but argue that God allows it for the purpose of "soul making," since evil is needed for genuine moral choice and also because the moral virtues (compassion, charity, courage, forgiveness, and so on) require the existence of evil in order to develop. The problem here is the enormous amount of gratuitous pain, suffering, and killing in the world - gratuitous because (1) much of the pain, suffering, and killing could not possibly serve the purpose of soul making since it does not come under human purview, and (2) there is far too much pain, suffering, and killing for what would be needed for soul making - a general case of far too much when much less would do.

Now add evolutionary time to this scenario: the mind-boggling amount of pain, suffering, and killing on this planet alone (there may be many more planets such as ours) of untold trillions of creatures spread over hundreds of millions of years - the fear and horror of predation, the torture of parasitism and disease, the agony of starvation, the brutality of temperature extremes - almost all of which never came under human purview or even contributed to human evolution in the slightest. God (assuming God exists) would have to be infinitely coldhearted in order to permit all of this.

In response, one might apply the idea of kenosis in Christian theology and suppose that God empties himself into his creation by experiencing the suffering of his creatures along with them - that is, subjectively, from the inside. But if true, that would do absolutely nothing to reduce the suffering of the countless trillions of creatures. There is an even deeper problem, however - one having to do with ends versus means. Quite simply, whatever the goal or purpose we ascribe to reality - the production of morally good humanoids, God-worshipping souls, or whatever else - this end cannot justly be called "good" given the enormous cost in suffering required to attain it.

A perfectly reasonable conclusion, given the problem of evil and the fact of evolution, is to concede the first part of the original conclusion - that there is no God. To my mind, this makes the most sense of everything. It should have to be conceded, however, that evolution and evil are in fact compatible with the existence of a God, just not the God of Western theology. Specifically, evolution and evil are fully compatible with a god that is, at most, omniscient and omnipotent, and that fits the definition of a "psychopath." That too would make a lot of sense. In that case, one might say not that God made man in his image, but that he made every one in a hundred of us in his image - which is precisely what one should expect a religious psychopath to believe.

David N. Stamos teaches philosophy at York University in Toronto, Canada, and is the author of a variety of publications, including Evolution and the Big Questions: Sex, Race, Religion, and Other Matters (Blackwell, 2008).