By Richard Hollis (aka Ritchie)

I thought I'd kick off the guest posts with a little philosophical thought experiment (hark, is that the sound of you all clapping your hands in glee?). When I wrote the following, I mean it fairly light-heartedly, but with an eye to the fact that we should perhaps remember we have less reason to be sure of ourselves than we may think.

Despite the insistence of many who champion it, Creationism does not qualify as a scientific theory under any reasonable definition of the term. It makes no testable predictions, invokes a supernatural agent and is supported by no observations of the natural world. But does that really matter? Could the theory of evolution, with all its mountains of empirical evidence, still be as irrational as Creationism?

Perhaps so. To see why, it is necessary to understand the difference between deductive and inductive reasoning. Both are ways of constructing an argument. The conclusions of a deductive argument however, are logically entailed by their premises. The conclusions of an inductive argument are merely supported by them.

Premise 1 – All horses are mammals.
Premise 2 – Mr Kips is a horse.
Conclusion 1 – Mr Kips is a mammal.

This is a deductive argument. The conclusion is logically entailed by the premises. It would be a contradiction to assert that the premises were true, and yet the conclusion was false.

Premise 1 - Horse no.1 is brown.
Premise 2 - Horse no.2 is brown.
Premise 3 - Horse no.3 is brown.
Conclusion 1 – All horses are brown.

This is an inductive argument. Here each premise acts as a single observation which supports the conclusion. Yet it is no contradiction to assert that while the premises are true, the conclusion may be false. Even if we had observed 100,000 horses and all of them were brown, this would still only act as inductive evidence.

Science is based on inductive reasoning. Observations are made, hypotheses are drawn up and tested, then critically challenged and re-tested, all under the assumption that the observations and results of the experiments are the result of static natural laws.

Indeed, it may be argued that inductive reasoning is the foundation for learned behaviour. If we put our hand on an open fire, the sensation will be extremely painful. Even from only one such experience, we will assume that coming into physical contact with fire will always feel the same and will avoid doing it again. Natural selection would punish those who did not learn from earlier mistakes. So it would seem that inductive reasoning is both reasonable and extremely useful for survival.

Yet there is a fundamental problem with inductive reasoning which David Hume outlined in his 1748 book An Enquiry Concerning Human Understanding. In a nutshell his argument states that induction rests on the assumption that natural laws are constant and uniform - and that this assumption is wholly irrational.

Stephen Law, in his book The Philosophy Gym, compares this to an ant sitting on a bedspread:

“The ant can see that its bit of the bedspread is paisley-patterned, So the ant assumes the rest of the bedspread – the bits it can’t see – are paisley-patterned too. But why assume this? The bedspread could just as easily be a patchwork quilt… We are in a similar position to the ant. The universe could also be a huge patchwork with local regularities, such as the ones we have observed – the sun rising every morning, trees growing leaves in the spring, objects falling when released, and so on – but no overall regularity.” (p156)

Such local regularities could have boundaries in time as well as space. Perhaps the natural laws of the universe change suddenly every 100,000 years – and the next change is due tomorrow! What is to say that we will not wake up tomorrow to find the sky is red, or that dropped objects remain suspended in mid air? Note that it is no defense to say, ‘the laws of nature have always stayed constant in the past’, since that is itself a piece of inductive reasoning.

The classic mistake is to misinterpret Hume’s argument. He is not saying that we merely cannot be certain of our inductive conclusions: he is saying that we have no reason at all to believe them. We have no justification for expecting the sky to appear blue rather than red tomorrow. Either is just as rational. And the theory of evolution, based as it is on inductive reasoning, is no more or less rational than Creationism.

In conclusion it seems – according to Hume, at least – that we are always unjustified in drawing conclusions via inductive reasoning. It is as rational to expect a dropped ball to float in mid air as it is to expect it to fall. If you think the first proposition sounds ridiculous compared to the second , then this may tell you far more about human reasoning than it does about logical induction.

But it would be a mistake for Creationists to see Hume’s argument as supporting their ideas. Creationism may be as rational an explanation for the existence of the Earth and life on it as any theory science has yet put forward. But, if so, then so is every other explanation you could possibly make up. To reach a point where Creationism is a rational alternative to the theory of evolution, we have reached a point where the whole of science is meaningless and all certainty we have in any knowledge has been cut loose. We really are as justified in believing in the Flying Spaghetti Monster as we are in believing in God.

According to the vast majority of religious believers (though perhaps not to the tiny minority of elite theologians), God is basically in nature like a larger and more powerful human being. He has plans and desires which he takes actions to fulfill; he likes some people and things and dislikes others; he experiences emotions like anger, jealousy, love, and forgiveness; he can be persuaded to act on another's behalf; and so on.

The most peculiar aspect of this anthropomorphic theology is its claim that God has preferences: he likes and desires certain states of affairs, while he dislikes others and desires that they not come to pass. For example, in the Old Testament, we are told that God desires animal sacrifice; the text repeatedly says that the smell of burning animal flesh is a "sweet savor" to him. Conversely, the worship of idols or gods other than himself is something he strongly dislikes, to the extent of visiting dreadful punishments on people who do it.

Christianity, too, says that God desires to forgive humanity for its sins, but also desires a blood sacrifice before he will consent to do so, thus necessitating the death of Jesus. The Christian god strongly dislikes the vice of pride, and harshly punishes those who seek to attain equality with him. In Islam, God desires that human beings worship him alone, rejecting belief in any partners; and in the nastier strains of Islam, we're told that God desires glorious martyrdom in battle and will reward anyone who does so with eternal glory.

The belief that God wants and desires certain things is a common thread in monotheism. But when you think about it, this is a profoundly strange belief. Most theists don't recognize this, but that's because the analogy between God and human beings masks the strangeness of it.

After all, we all understand how, and why, human beings come to hold certain desires. We have instinctual physiological drives, installed in us by evolution, for basic things like food, sex and companionship. We have more complex desires as a result of culture, upbringing and past experience for things that we think will add to our happiness or help fulfill the more basic desires. Every one of us has gone through a long, complex and contingent process of development that shaped our likes and dislikes.

But God, so we're told, is eternal and unchanging. He is pure reason, pure mind, pure spirit - no physical needs to fulfill, no past history, none of the contingent events that make human nature what it is. So how is it that he has, just like us, a complex nature with specific likes and dislikes? He did not undergo the process by which human beings acquire their preferences, so where does he get them from? Why does he prefer things one way and not another?

Some believers may find this question difficult to comprehend, so as an imagination-stretching exercise, allow me to propose a variety of different preference sets which it seems, a priori, that God could have had. I invite theists to consider these possibilities, and to ask themselves: why is it that God is this way and not one of those ways?

• Self-Sufficient God. This deity knows himself to possess all perfections and sees no reason to create any inferior sentient beings. Therefore, he sits alone in the void for all eternity, contemplating his own perfection, and never creates a world separate from himself.

• Sadistic God. His greatest desire is to see maximal human pain and suffering. He desires no worship, offers no opportunity for salvation, and answers no prayer, but deliberately creates a world as hellish as possible and peoples it with sentient beings just so that he can watch them suffer for all eternity.

• Moral Relativist God. He creates a world and peoples it with sentient beings, but has no motivation to care about what they do to each other, any more than a person who owns an ant farm would care about the morality of the ants. He gives no commandments and sets no rules, but watches us for his own entertainment, regarding both great acts of good and terrible acts of evil with the same bemused detachment.

• Recluse God. His greatest desire is to be left alone. Prayers, acts of devotion and other worship just annoy him, and he has an afterlife of punishment set aside for those devout people who constantly bother him. The people whom he'll reward are the atheists, because at least they let him get some peace and quiet.

• Prankster God. His greatest desire is to do the opposite of what we expect (he finds it hilarious). Whenever people pray for something, he does the opposite. When people seek him, he hides from them; when people ignore him, he reveals himself to them. The people who are most certain they're saved, he'll doom to an afterlife of punishment, and people who don't believe in an afterlife will be admitted to a blissful heavenly realm. He's constantly leaving misleading clues and sending incompatible revelations to the world, just to keep us further confused.

Granted, some of these hypothetical gods sound bizarre. But how are they any more bizarre than a god who prefers one particular race of people above all others, or a god who demands the shedding of innocent blood to forgive sins, or a god who demands five prayers at specific times each day, or a god who desires that we ritually consume his flesh and blood each week? It's only familiarity that makes these seem natural while the ones I've proposed seem strange.

There's an interesting parallel here with the "fine-tuning" argument sometimes used by religious apologists. They ask how likely it is that a universe with physical laws conducive to life could just happen to exist with no prior explanation. But atheists can ask an analogous question in return: Out of all the billions of possible gods, each one with a different highly specific and arbitrary set of desires and preferences, how likely is it that there just happens to be one who's benevolent and kindly disposed toward humans? What prior cause can explain that favorable coincidence?

The story goes that the renowned physicist Richard Feynman was once asked to summarize the most important finding of modern science in a single sentence. Feynman replied, "The universe is made of atoms."

Although there are many other scientific discoveries that are arguably of equal importance, Feynman's choice makes a lot of sense. The discovery of atoms is so familiar to us that it's easy to overlook its breathtaking significance. We know, at the smallest scale where it still makes sense to talk about distinct objects, what are the fundamental building blocks that matter is made of, and we have described their interactions with astounding precision. Our understanding of everything from why the stars shine, to how DNA replicates, to why a table is solid, relies on our knowledge of the way atoms behave.

Atomic theory is now so well-established, and so widely accepted, that it's easy to forget how controversial a notion it originally was. In fact, atomism was once synonymous with atheism, and it was the bête noire of Western religion not just for centuries, but for millennia.

It was in the fifth century BCE that the Greek philosophers Leucippus and Democritus first proposed the idea that matter was composed of indivisible particles called atoms. But these ideas came to their fullest flowering in the mind of their successor, Epicurus, who lived around 300 BCE. In Epicurean philosophy, the world was ultimately comprised of atoms and the void. All that exists and all that occurs - from flowing water to burning fire to human thought - is due to the movement and collision of atoms and the endless, ever-changing array of patterns they arrange themselves in. The ruling principles of the Epicurean cosmos are natural law and random chance, not purpose or plan, and we who live in it and are part of it can find happiness by learning to accept whatever happens with virtue and tranquility. Epicurus did believe that the gods existed - he saw this as the only way to explain the widespread dreams and visions of them - but in his philosophy, they were not supernatural spirits but material beings composed of atoms, just like humans. More importantly, they did not take any interest in human affairs; they were more like images than actual persons.

In scientific terms, it's impressive how much Democritus and Epicurus got right. They correctly anticipated the very discovery that Richard Feynman called the most important element of modern science. Epicurus even believed that atoms sometimes exhibited "random swerves", a startling point of agreement with modern quantum mechanics. If he had claimed that a god told him all this, it would have been by far the most impressive example of theism anticipating later scientific discovery, and genuinely difficult for an atheist to explain.

Yet to the theologians and churchmen who came after him, Epicurus' ideas were the depths of heresy. His materialist notion of the cosmos - no creator deity, no life after death, everything that exists made of patterns of atoms - was anathema to the monotheist conception of an orderly cosmos arranged and guided by God. For centuries, being accused of "Epicureanism" was a very serious charge indeed. For example, the Jewish writings known as the Mishnah, in 200 CE, had this to say:

And these are the people who do not merit the world to come: The ones who say that there is no resurrection from the dead, and those who deny the Torah is from the heavens, and Epicureans.

Indeed, the Jewish word for "heretic" - apikoros - appears to be a Hebrew transliteration of "Epicurean". The Hebrew benediction known as the Amidah, which is recited three times daily by observant Jews, contains a prayer which asks that "may all the apikorsim be destroyed in an instant" (source).

As Christianity became ascendant, it treated Epicureans no less kindly. Acts 17:16-18 records how the first Christians viewed them:

"Now while Paul waited for them at Athens, his spirit was stirred in him, when he saw the city wholly given to idolatry. Therefore disputed he in the synagogue with the Jews, and with the devout persons, and in the market daily with them that met with him. Then certain philosophers of the Epicureans, and of the Stoicks, encountered him. And some said, What will this babbler say? other some, He seemeth to be a setter forth of strange gods."

Early Christian apologists such as Tertullian, Jerome and Augustine reviled Epicurus, calling him a "pig" and an advocate of "depravity and gluttony", and his philosophy a "frigid conceit" (source; see also).

Throughout the Middle Ages, as Christianity gained secular power, the ridicule and persecution grew worse. The Byzantine emperor Justinian I, who actively suppressed non-Christian faiths, closed down the philosophy schools of Athens, including the Epicurean Garden, which had survived for eight hundred years. The twelfth-century philosopher Nicholas of Autrecourt, who taught an atomist doctrine similar to Epicurus', was condemned and forced to recant and burn his writings. In the Divine Comedy, Dante depicts Epicurus and all his followers "who with the body make the spirit die" as imprisoned in flaming tombs for all eternity. As late as the 1600s, Epicurean theories were reviled, as one pamphleteer wrote: "Let that beastly Epicure's mouth be now sealed up in dumb silence."

Yet Epicurus, that sly old Greek, had the last laugh. The church persecuted his followers and sought to stamp out his teachings, but not only did Epicureanism survive, it was vindicated. The universe is made of atoms after all. Natural phenomena like weather, the growth of crystals, even the currents of human motion and thought can be traced back to patterns of atoms and their ceaseless ebb and flow. As in many other areas, this is one where religion arrogantly thought to wade in before science had had its say, and was forced to retreat. We do not live in the medieval church's world, where our bodies are just so much fleshly dust powered by immaterial currents of spirit, and the heavenly bodies move in spheres of celestial ether. We live in a grand cosmic clockwork of atoms and molecules, a vast mesh whose unfolding is determined by random chance and the immutable laws of cause and effect. We live in Epicurus' world.

As any regular reader of Daylight Atheism knows, the topic of morality is a major concern of mine. In essays on Ebon Musings, I've sketched out a secular moral theory I call universal utilitarianism. Here on this site, In the past, I've written about the roots of this morality and the virtues that can be derived from it, as well as musings on what UU has to say about some controversial moral topics. In 2009, I plan on taking these explorations in a new direction.

This year, I intend to write some posts further detailing universal utilitarianism and how it can respond to difficult ethical dilemmas - not the practical dilemmas that we encounter in daily life, but thought experiments specifically dreamed up to stretch moral philosophies to the breaking point. If UU can survive being tested in this way, then I think we'll have greater reason for confidence that it can cope with everyday issues. I've already written about one such problem, the "trolley problem", in "The Doctrine of Double Effect". Today I'll confront a different one.

Today's post concerns the Happiness Machine, a hypothetical invention that produces pure pleasure for the user in unlimited quantities - say, an electrical implant that stimulates the brain's pleasure centers, producing a feeling of bliss at the push of a button. It's undeniable that universal utilitarianism counsels us to seek happiness as the highest good. If we follow UU, then if this machine is invented, should our highest goal be to hook ourselves up to it for the rest of our lives?

Lynet, of Elliptica, has an answer in Challenging the Paramounce of Happiness:

I wouldn't. It would be like dying. Even with heaven included, I don't want to die.

I suspect many of my readers share this intuition, as I do myself. Intuitively, there's something deeply repellent about this scenario, but what is it, and can UU justify this intuition despite its promotion of happiness as the highest good?

The first thing to note is that the Happiness Machine is not an entirely hypothetical scenario. It strongly resembles a real-world phenomenon: the use of narcotic drugs for pleasure. And, if such a machine were ever invented, we can be fairly confident that users would end up in much the same way as addicts of these drugs.

First of all, what would keep users of this machine alive? If the Happiness Machine works as advertised - if it truly replaces all suffering with total contentment - then it will make you oblivious to your need for the necessities of life. We satisfy our bodily needs, in the end, because it causes suffering if we do not. If they cannot feel this suffering, users of the Happiness Machine will soon die of starvation and dehydration and miss out on all the further happiness they might have had in a longer life. Clearly, this is not a good outcome.

But if that problem could be solved, another would rapidly follow. Pure sensory pleasure will soon become insipid and unsatisfying. The human mind habituates: if you constantly experience a high level of pleasure, it does not remain equally pleasurable indefinitely. Rather, it soon becomes the base level against which new experiences are judged. The same stimulus produces a steadily diminishing reward. If you use the Happiness Machine often, soon it won't be a source of bliss, but something you'll need to use constantly just to function, and ordinary activities without it will become unbearable. Like any other drug addict, you'll experience a brief period of pleasure, but it will be followed by a much longer period of misery and dependency. In the long run, it will cause far more suffering than happiness, and might even permanently impair the brain's capacity to take pleasure in anything else.

And what about the potential loss of independence? If someone controls the master switch for all the Happiness Machines, or if they hold the patent and are the only ones who can repair it, they will have a population of slaves. The addiction which such a machine would produce would render its users utterly dependent on whoever can supply that continued jolt of pleasure. To anyone who values freedom and autonomy, the thought of being controlled by another in this way ought to be intolerable, and again, a sure pathway to a life of misery and servitude.

The only way to avoid habituation and dependency is to live a life with not just one source of pleasure, but a variety of meaningful pursuits. The most enduring and fulfilling kind of happiness is the kind that has this rich texture of knowledge and experience, the kind that only comes from interacting with the world. (If nothing else, the more you know about what's out there, the better a position you're in to appreciate the things you really like.) Running a wire into the pleasure neurons of the brain is a poor substitute.

Finally, excessive use of the Happiness Machine undermines the development of empathy that UU holds as the highest moral virtue. After all, UU does not counsel us to only seek pleasure for ourselves, but to live in the world and be the source of happiness for others, to work to defeat suffering and improve the lives of our fellow humans. Someone who is anesthetized by this machine, cocooned in a blissful coma and deaf to the cares of other people, is not acting in accord with the principles of UU but against them. Like a greedy millionaire who hoards his wealth and refuses to give to charity, addicts of the Happiness Machine are not doing good but merely indulging their own selfishness.

In the past, I've written about the origins of religion and how belief in gods likely arises from one of humanity's most common psychological fallacies, the tendency to attribute agency where none exists. (When was the last time you got angry at your computer and felt as if it was trying to balk you? It happens to me much too often - even when I know there's no one inside there.)

There's another, related tendency that often manifests in religious belief, which is that human beings are concrete, categorizing thinkers. Our ability to create abstractions and parse the world into categories is a very successful strategy, one that forms the basis of our science, but it can be taken too far. That point is passed when we lose sight of the fact that our abstractions and categories are just mental conveniences, and begin treating them as if they were real things in their own right. In short, we're susceptible to reification.

One species of reification is the belief that things of this world inherit their nature from cosmic archetypes that exist on another plane. This, of course, is Plato's idea of "eternal forms", and the influence it's had on religion has been enormous. In all the offshoots of Judaism, Christianity and Islam, we find beliefs about how things that exist on Earth are imperfect reflections of perfect processes in Heaven. Thus, in Christianity, we encounter beliefs that the ritual animal sacrifices of Temple Judaism were inferior precursors to Jesus' once-and-for-all sacrifice of himself. In Islam, each earthly copy of the Qur'an is thought to be a mirror of a preexistent heavenly copy.

But more than anything else, the belief in forms has been the underpinning of creationism. To the naive observer - and the most creationists past and present certainly fall under that category - most living species appear to be distinct, and this supports their conclusion that all life can be classified into "created kinds", which are divided from each other by boundaries beyond which evolution cannot go. Of course, if you include all living species and not just a few carefully chosen representatives, many of the seemingly wide gaps shrink by a significant margin; if you include the many more extinct species known to us by fossils and other traces, those gaps contract still more; and if you examine the genetic commonalities that form a nested hierarchy of descent, the gaps disappear entirely.

A similar concept is the idea of the "essence", as if the qualities that define a thing had an objective existence all their own and could be distilled and extracted like a rare liquid. Again, it seems to be natural for us to think in this way. Consider how easily we accept the notion that Cupid's arrows could be coated with the pure essence of love or that a particular stone or plant could be impregnated with good luck, or how many tribes have believed that they would acquire the qualities of animals by consuming those animals. Or consider the classic sci-fi plot, dating back to Robert Louis Stevenson, of splitting a person into their "good side" and "evil side" - as though these were two separate essences mixed together in the same body, and one or the other could be made to precipitate out of solution by the right technique.

But most of all, the idea of essences gave birth to the notion of the soul. It causes people to think erroneously that the information-processing activity of the mind is not just the product of the brain's functioning, but a separate thing in its own right that can exist independently and survive the death of the body. Given what we now know about how the brain works, this makes about as much sense as believing that a computer could continue to process data and display programs after its hard drive and CPU have been melted down. But when our tendency to reification is not checked by evidence, humans are natural dualists, and find little difficulty in believing in ghosts in the machine.

When well-chosen, our mental patterns accurately capture the way the world is organized and may even point to hidden truths. Consider the twin nested hierarchy of evolution, or Mendelev's successful prediction of undiscovered elements based on the gaps in his periodic table. But even in this case, we must take care to resist the trap of reification. Many superstitions have been born in the minds of people who failed to realize that the patterns they saw were descriptive conveniences, artifacts of human perception, and not things in their own right.

Among the band of philosophers who hold that free will is supernatural, one of the reigning ideas is called agent causation. This hypothesis states that volitional acts are a special category of event, one that is caused not by any other event but - in some deeply mysterious way - by the agent itself. Philosopher Roderick Chisholm describes this as follows:

If we are responsible... then we have a prerogative which some would attribute only to God: each of us, when we act, is a prime mover unmoved. In doing what we do, we cause certain events to happen, and nothing—or no one—causes us to cause those events to happen.

The consequence of agent causation is that free will is not a process but some sort of irreducible substance: one that spontaneously originates acts and decisions, unconnected to the causal chain that binds together all other causes and effects. The usual apologetic corollary is that even God cannot intervene in or influence this process short of destroying free will altogether. It's plain that this is just the religious doctrine of the soul, the supernatural "ghost in the machine", portrayed in technical philosophers' language.

Agent causation depicts human free will as a binary state - a quantity which can either be present or not present, but which has no internal structure and cannot be subdivided. However, this is obviously false, which makes this entire view unsustainable. Free will is not a mathematical point; free will is a complex bundle of contingent desires, habits, and predispositions, which can be added to, altered or removed.

You can determine this by empirical studies of human behavior. There are countless things that human beings could do that we do not do and do not feel any desire to do. On the other hand, the vast majority of us do experience desires to have sex with an attractive partner, to consume foods high in fat and sugar, or to form tight emotional bonds with parents and relatives. Human free will, then, is not just an irreducible point source that bubbles up actions at random; it operates within a defined set of parameters, giving rise to a predictable variety of behaviors (anthropologists call them cultural universals).

You can also determine it by the evidence of the human brain: it's well known that certain, specific kinds of brain damage alter desires and behavior in predictable ways. Dementias such as Alzheimer's disease often cause loss of interest in religion, while epileptic seizures in the temporal lobes can induce religious experiences. Damage to the frontal lobes leaves people unable to control their behavior or ignore sudden impulses; injuries localized to the left hemisphere often cause depression, while injuries to the right can leave people constantly and inappropriately euphoric. And of course, drugs and intoxicants also have reliable, predictable effects on behavior.

If free will was an irreducible, nonphysical substance, producing actions free from external causation, then we should not see brain damage affect desires or behavior - much less change them in the predictable ways that neurologists observe. That we do see this shows beyond a reasonable doubt that it is false that "nothing... causes us" to make the decisions we do. Our decisions manifestly are caused.

Of course, there are other varieties of supernatural dualism that are not as clumsy as agent causation. But what these other varieties have in common is that they must give up the line in the sand. They cannot declare, as agent causation does, that we are purely supernatural beings whose decisions ultimately arise from the soul and nowhere else. Instead, these other dualisms must acknowledge that we are, at least in part, material beings, and that changes to the physical composition of body and brain can affect and alter our selves. Whether they realize it or not, advocates of these beliefs are drawing closer to atheism, as they implicitly grant that we are not spirits whose choices arrive from outside the world, but physical beings whose acts are an inextricable part of the fabric of cause and effect.

In last month's post "Down to Earth", I discussed Thomas Jefferson's ideal of rich simplicity, what Buddhism calls the Middle Way. Rather than the vain pursuit of happiness through the acquisition of power or material possessions, the true source of contentment lies in the simple pleasures of life that are available to everyone, regardless of social status.

Some of the comments mentioned Epicurus, a person I should write about more often. Epicurus was an ancient Greek philosopher who taught a system of values that was more like modern secular humanism than any other philosophy of the past (with the possible exception of the Carvakas). Although he believed that the gods existed, he taught that they were material beings who took no interest in human affairs, or in anything besides their own blissful contemplation. He also taught that death was not to be feared, because the person who is dead no longer experiences anything and therefore is not suffering.

Epicureanism put the emphasis on pleasure, not as mindless hedonism but as reasonable indulgence in the good things available in life. Valuing intellectual pleasure more highly than sensual pleasure, it recommends the cultivation of friendship, an ethic of simplicity, and an attitude of tranquility in the face of life's trials. Ironically, "epicure" in popular parlance has come to refer to a connoisseur of food and drink, which Epicurus arguably considered the least important of life's pleasures.

The Epicurean view stands in opposition to the religious idea of imaginary crimes, where certain activities are forbidden not because they cause any harm to human beings, but solely because they're believed to displease God. I consider that, when it comes to attracting people, this is an advantage for atheism: we don't have to teach excessive self-denial, nor demand that people abstain from things they would like to do just because an ancient dogma says not to. Nor do we have to teach, as many religions do, that happiness is frowned upon and that the proper attitude toward life is one of renunciation or constant repentance. We should not promote thoughtless indulgence, but we can teach that people can partake responsibly in the good things of life.

For instance: We do not have to believe, as some religions do, that certain foods are off-limits and may not be consumed no matter what. I respect the opinion of people who abstain from eating meat on ethical grounds, but the arbitrary nature of religious dietary restrictions - demanding that foods be prepared only in certain specific ways, forbidding the mixing of foods that are perfectly allowable individually, or banning the eating of some animals but not others that are equally sentient - is nothing but irrational self-denial. An atheist can be a true gourmet, sampling all the different flavors and cuisines of human culture, and tasting the full palate of sensory experience.

We do not have to believe, as many religions do, that alcohol and other intoxicants are sinful or forbidden. Again, there are people who abstain from these substances for valid reasons. But a mature and rational adult is certainly capable of making responsible use of them, and there is nothing intrinsically wrong with that. The quest to alter one's consciousness for pleasure or ritual is as old as humanity, and in moderation, is a source of harmless relaxation and enjoyment.

We do not have to believe, as nearly all religions do, that sex is a mysterious and dangerous thing that must be practiced according to strictly prescribed rules. Everyone is familiar with the arbitrary and irrational restrictions that religious belief places on sexual expression: that sex should never be simply for the sake of pleasure; that you should only have sex with one person over the course of a lifetime; that women should not exercise sexual autonomy; or that sex is always immoral unless a member of the clergy gives consent. None of these rules are grounded in reason; they spring from ignorance, superstition and fear. Sex has real power to form (or shatter) emotional bonds, and if practiced irresponsibly, to lead to the spread of disease or unintended pregnancy. But sexual expression is enriched by diversity just like every other area of human culture, and an atheist knows that there is more than one way to have a healthy sex life.

In essays such as "Three In One", I've scorned the Christian doctrine of the Trinity:

If a claim is labeled beyond our ability to understand, then how are we supposed to tell if it is true? What assurance do theists have that the Trinity is a true fact about the world that is genuinely beyond our ability to comprehend, as opposed to a false claim invented by people whose illogical nature is protected from scrutiny by labeling it a mystery we aren't intended to understand?

But is this claim too hasty? A Christian site admits the idea seemingly defies logic and reason, but compares it to modern scientific theories that also have highly counterintuitive implications:

It a strict sense, the doctrine of the Trinity does not violate logic at all—at least no more than quantum physics or general relativity.

We can talk about it rather thoroughly. What we can't do is imagine how it could work. But the same is true for quantum physics and relativity.

It's true that the analogies proposed to explain relativity, like depicting spacetime as a rubber sheet, on the surface seem no more or less comprehensible than C.S. Lewis' analogy of the Trinity as a cube:

On the Divine level you still find personalities; but up there you find them combined in new ways which we, who do not live on that level, cannot imagine. In God's dimension, so to speak, you find a being who is three Persons while remaining one Being, just as a cube is six squares while remaining one cube. Of course we cannot fully conceive a Being like that: just as, if we were so made that we perceived only two dimensions in space we could never properly imagine a cube.

But there is a significant point of difference here, which is that in the case of general relativity or quantum mechanics the analogies, are not the whole of the theory. The analogies are just superficial descriptions of an intricate and incredibly precise mathematical framework that allows us to make confident and astonishingly accurate predictions about the natural world. We do not need to be able to fully grasp the principles involved, because we can test and verify in a quantifiable way that the idea is true.

But with doctrines like the Trinity, there is no deeper understanding, no underlying mathematics. The vague and imperfect analogies are not backed by a model of precise predictive power; the vague and imperfect analogies are all there is. From the vantage point of the naive observer, these two might look similar, as I wrote in "The View From the Ground". But it is a false equivalence: though they both have an outer structure of metaphor and analogy, one of these ideas is backed by a solid core of evidence, while the other is built on insubstantial air.

Imagine, in some medieval monarchy or modern-day oligarchy, that the government passed a law which made it a crime to deny that the sun exists.

No country either ancient or modern has ever done this, and it's easy to see why. Who would ever be tempted to deny the existence of the sun? The evidence to the contrary is undeniable. It's large, it's obvious, it's blindingly brilliant - it's just there. There are no rational grounds for claiming the sun does not exist; only a fool or a madman would choose to do so. Even if some sower of discord or false prophet made it part of his mission, the sun's existence is so obvious that he'd stand little chance of persuading others to join him in such a mad quest. No state intervention would be needed to dissuade the populace from following along.

Clearly, there's no need for anti-sun-denying legislation. Why, then, have kings, priests and mullahs through history so often passed similar legislation which makes it a crime to publicly doubt the existence of God?

There are billions of theists around the world who hold a very unusual set of beliefs. On the one hand, they believe that God is the all-powerful Creator of the cosmos and all that is in it, the Sustainer whose moment-to-moment providence is the only thing that keeps the machinery of nature running. Some go so far as to believe that God is the underlying ground of being without whom the very notion of existence is meaningless and void. And yet, on the other hand, many of these same people believe God is hidden, and cannot be found through evidence but only believed in by faith.

What an utterly bizarre conjunction of beliefs this is! Does it make any sense at all to believe that God would hide himself? On the contrary, the only conclusion that I can comprehend is that, if such a being as God existed, his existence would be even more undeniable than the sun that lights the sky. It would be a truth so obvious that the idea of outlawing atheism would never even occur to anyone.

But there have been anti-blasphemy laws throughout history. They have been quite common. We can draw an important conclusion from this. Clearly, God's existence is eminently deniable. If it were otherwise, there would have been no need of such laws in the first place. The only reason such a statute would exist, as Robert Ingersoll said, is so that whatever was lacking in evidence could be made up for with force. The very fact that the authorities sought to enforce conformity shows that it would not come about on its own.

One possible rejoinder is that the sun clearly does not care whether its existence is denied - it continues to shine down regardless - whereas God's favor is fickle, and it may be inviting disaster to doubt him. Thus, the state must enforce uniformity for people's own good. But even if the premise of this argument is true, the conclusion does not follow. The state can regulate people's outward actions, but it cannot control their inmost thoughts. Even if people are required to mouth the correct words of allegiance, privately they may be giving voice to whatever thoughts they please. Since every religious tradition agrees that God can see into our hearts, and presumably would be enraged by private blasphemy as well as public, any attempt to secure his blessing by passing mortal laws would be an exercise in futility.

Inspired by a recent post on Philosophy, et cetera, I want to talk a little about zombies and what they imply for a materialist theory of the mind.

When I say "zombie," I don't mean the shambling, flesh-eating undead of horror films. This thought experiment is about philosophical zombies, which are a different beast altogether. The philosophers' zombie is a hypothetical creature which, to all outward appearances, is indistinguishable from an ordinary human. The difference is that they lack phenomenal consciousness - they lack qualia.

Qualia are the subjective sensory perceptions of our inner mental life. We see colors: the redness of red, the greenness of green. We hear tones, sharp or high-pitched or dull or low. We taste flavors, salty or bitter or sweet. We feel emotions like joy, anger, or sadness. Zombies, by contrast, have none of these experiences. They are not truly conscious of anything, any more than a stone is conscious, but they act exactly as if they were. A zombie can duck a thrown baseball or write a restaurant review. Point a gun at one and it will flinch and act as if it were afraid.

What does such a bizarre idea have to do with atheism? The answer is that some prominent philosophers claim that zombies are a conclusive disproof of any strictly naturalistic theory of how the mind functions. The train of argument usually goes that zombies are not a metaphysically impossible notion; it involves no self-contradiction to imagine their existing. If they are not self-contradictory, then they are possible. If they are possible, then we could hypothetically build one - a sophisticated robot, let's say. Such a being would act with rationality and apparent intelligence, yet lack consciousness. But if it's possible to be an intelligent, rational being without consciousness, the question is, why aren't we zombies? What makes us different from the robot? The answer, they say, is that there must be a supernatural component to the mind, in other words, a soul. This supernatural component is what gives us our consciousness, our qualia, whereas a being lacking that component could never truly be conscious no matter how much mental processing power it might have.

The problem with zombies, as with many philosophical notions, is that they do not truly prove a point but simply play on people's differing intuitions about what is possible. No obvious self-contradiction arises when we imagine a zombie, I grant. It is logically possible for such a thing to exist. But that does not mean that zombies are possible in our world, under the laws of physics that hold sway here. Our ability to imagine them is no disproof of this. We, fallible humans, are not cognizant of all the laws of physics, much less their almost infinitely complex hierarchy of ramifications. An intelligence like Laplace's demon, with perfect knowledge of the universe, might well see some consequence of physical principles which we overlook, and which renders zombies impossible in our world.

Consider a similar example. Just as dualist philosophers claim they can imagine creating a zombie, I claim I can imagine creating a perpetual motion machine. I couldn't tell you exactly how to build it, just as no one can say exactly how to build a zombie, but I can readily imagine some marvelous machine - blinking lights, coils of wire conducting electric arcs, spinning flywheels, a big brass switch - that, once it's powered up, begins producing free energy out of nowhere. No self-contradiction arises when I imagine this. But does that mean we can actually build one? Have I just disproved the laws of thermodynamics without getting out of my armchair?

Obviously not. Though we may think we can imagine a working perpetual motion machine, reality is bound to disappoint. So far, every attempt to build one has ended in utter failure, stymied by some physical principle they failed to take into account. The laws of our universe, it appears, interlock in such a way as to perfectly rule out the possibility of perpetual motion machines. There is no loophole where an inventor, however clever, can slip through. It only seems possible because our imaginations do not take into account the critical details that any practical attempt cannot avoid.

The dualists, I believe, are in the same boat. They may think they can imagine zombies, but that doesn't mean they're actually possible. Indeed, I suspect the opposite is more likely true: any creature complex enough to behave with all the creativity and adaptability of a human being would have to have consciousness and qualia, or something very much like them.

After all, how could a zombie dodge a thrown baseball, unless its eyes (or cameras) conveyed images of nearby objects; unless those images were in some way converted into an internal model of the world; and unless that model contained some data stream or symbol which represented a small, round, rapidly approaching object? How could a zombie write a restaurant review unless its chemical sensors were linked to a sophisticated mapping of what readings correspond to what flavors and the many subtle ways in which various combinations could interact with each other? How could a zombie convincingly simulate fear unless it had a wide-ranging ability to keep track of events in the external world and infer which ones could pose a threat to its continued existence?

It is not at all obvious to me that a being with such a sophisticated repertoire of memory, understanding and perception could fail to be conscious. In fact, I strongly suspect the opposite: any being with this capability would have to be conscious, given the physical laws that hold in our world. Consciousness is not an optional add-on, but an inevitable product of a certain degree of cognitive sophistication. In particular, I believe the ability to explicitly represent one's own self in one's mental catalog of objects, and to introspect one's own internal information processing - which, again, a zombie can do - is a vital building block of true consciousness as humans possess it, if it is not consciousness itself.

The dualists assume that an intelligent being could fail to possess qualia, and therefore conclude that intelligence and consciousness are separable. But this claim is an example of the fallacy of circular argument. If you assert that it's possible to hold everything else about the world constant, but subtract consciousness, then you're not arguing for dualism, you're assuming dualism! The conclusion which you wish to reach is already contained in the starting assumptions you feed into your argument. Whether consciousness is an inevitable outcome of the working-out of physical laws inside intelligent brains, or whether it's an unnecessary epiphenomenal accompaniment, is the very thing at issue. I argue that, contrary to some people's intuition, consciousness and intelligence are in fact not separable. I can't prove it; but neither can the dualists prove that they are.

The only remaining question, which I admit is a vexing one, is: why qualia? Why does consciousness have any subjective character at all? The way in which our minds represent characteristics of the external world as ineffable interior perceptions does seem strange, and not like most other phenomena we encounter. It does indeed seem difficult to imagine that any science, however advanced, could explain precisely how such subjective experiences arise from the collisions of atoms inside the brain.

But our inability to imagine it, at this point in time, is no proof that it's impossible. The existence of life was also once considered to be an impenetrable mystery, inexplicable except by postulating a supernatural "vital force". Yet life has since been shown to have an explanation comprehensible in terms of physical laws. (Overcoming Bias writes about "encapsulating the mystery as a substance" - an apt description of the situation.) I see no reason to believe that qualia will prove to be any different. Though they may seem to be a fundamentally different kind of thing, that's just an artifact of our present ignorance. Most likely, qualia arise from the physical laws of the cosmos no less than any other natural phenomenon. We don't understand precisely how - and maybe the mysterians are right, and we never will - but still, that is no proof that it is impossible.