On the face of it, there's no reason not to dissect religion with the same tools used to pick apart animal behavior. Why can't we ask how religion evolved? What's wrong with trying to figure out whether cleaving unto God enhanced our ancestors' chances of survival, or whether, on the contrary, religious belief occupied them like a parasite, sickening healthy minds with delusional notions?
And yet this approach to religion has long been perceived as a breach of intellectual protocol. Ever since the 18th century, when Immanuel Kant carved up the world between pure reason (science) and practical reason (morality), science has more or less kept to nature, while religion—the nonfundamentalist kind, anyway—has largely confined itself to ethics and the meaning of life. Raids by one party on the camp of the other have invariably ended in name-calling. "Reductionists! Imperialists!" the theologians cry whenever naturalists start making notes and drawing charts. "Relativists! Anti-rationalists!" the scientists retort upon encountering philosophers who wonder whether science is but one descriptive system among others and not the high road to truth.
In Breaking the Spell: Religion as a Natural Phenomenon, Daniel Dennett promises to break the impasse, or at least to map a course for research that would redraw the traditional boundaries between science and religion. Evolutionary theory, he says, can tell us why religion evolved and what it was meant to achieve, which means it can explain why the religious act the way they do. In an age of growing fanaticism, this seems a claim worth paying attention to. And Dennett seems the man to make good on it. A philosopher of mind—he has written acclaimed books on consciousness and evolutionary theory—Dennett knows how to argue about science and how to argue from within it. A militant atheist, he doesn't promise to keep an open mind about religion. But in theory, at least, his frankness adds value to his opinions.
As Dennett knows full well, the biggest challenge for anyone who wants to put religion under the microscope is figuring out what goes on the slide. What is religion, anyway? How can you tell it apart from ideology or philosophy? How do you distinguish religions, with their quirks and presuppositions, from nationalities or professions, with their quirks and presuppositions? How is being Catholic different from being American, or being a human rights worker?
These may seem like small quibbles, but they have big consequences. We'd be foolish to single out religion for evolutionary investigation if there is nothing about it that is unique. If religions are just cultures, if religious rituals are functionally indistinguishable from other irrational habits, if a religious idea, or meme, Dennett calls it, is just one more way of interpreting the world, then we ought to be asking much broader questions, such as, why do humans have a penchant for peculiar rituals? Trying to explain religion through evolutionary theory would be as frivolous as trying to understand skateboarding by means of physics.
Dennett's definition of religion, however, swats away all such complications with a satisfyingly commonsensical solution. Religions, he says, are "social systems whose participants avow belief in a supernatural agent or agents whose approval is to be sought." Only one part of this statement is actually meaningful. All discernable cultural groups are social systems, and all coherent social systems evince some system of authority—their participants seek approval from somebody or other. What sets religion apart, then, is that its participants avow belief in a supernatural agent or agents. In other words, they aver belief in a God or gods.
Saying that the religious express belief in a deity certainly seems like the obvious way to describe them. But Dennett's definition should give pause to anybody who has ever gone to church or synagogue without being sure why. How does Dennett account for all the people who practice religion without ascertaining whether or not they believe in God?
Dennett has foreseen the objection, which is why he makes "avow" the chief verb in his definition. People don't have to believe what they're saying when they utter prayers in order to be classified as religious. They just have to say the words. But Dennett can't rely on this trick alone, because if everybody avowed belief without meaning it, we'd be back where we started. Religion would be made up of no more than the usual inexplicable cultural activities, like declaiming poetry or shunning dog meat.
So, Dennett has to invent another concept: "belief in belief." He devotes an entire chapter to this troublingly attenuated notion. People who believe in belief, he says, believe that civilization needs myths to live by, so we mustn't examine religious ones too closely. Belief in belief is the compromise formation of those who can't bring themselves to evince a naive belief in a supernatural being but think religion is a useful construct that ought not to be toppled.
You'd have a hard time convincing a true believer that anything as second-order and instrumental as "belief in belief" constitutes belief. Dennett doesn't really think so, either. He sees it more as a falling away from belief, a latter-day apostasy that doesn't recognize itself as such. By the end of his chapter, having dismantled "belief in belief," Dennett excludes from his definition of religion all cosmologies that do not require one to acknowledge the literal truth of the proposition that God exists, or at least gods who are "effective agents in real time." Thus, for instance, he rules out deism, the view that God acts through natural laws, and incidentally Charles Darwin's credo for much of his later life. "If what you hold sacred is not any kind of Person you could pray to, or consider to be an appropriate recipient of gratitude (or anger, when a loved one is senselessly killed), you're an atheist in my book," writes Dennett. "If, for reasons of loyalty to tradition, diplomacy, or self-protective camouflage (very important today, especially for politicians), you want to deny what you are, that's your business, but don't kid yourself."