Daniel Dennett has written about free will, consciousness, the mind, evolution, and natural selection. In his latest book, Breaking the Spell: Religion as a Natural Phenomenon, he turns his attention to a new topic, the origin and role of religion in the human species. Although Dennett is avowedly an atheist, this book is not about whether God exists per se. Instead, it is more an exploration of how it came about, what purpose it served in the past and what purpose it serves today, and whether belief in it does more good than harm or vice versa. As the title suggests, Dennett's thesis is that religion is a "natural phenomenon", in the sense that it is a phenomenon that obeys the laws of nature, laws that we can study and learn.
There are many religious people who would consider the prospect of scientifically investigating their beliefs, both how they originated and what they are good for, to be impious, even blasphemous. This is the "spell" that Dennett alludes to in the book's title, the spell he argues must be broken for society's sake. As he says, if believers are right that the best way to live a good life is through religion, we should investigate that so that we all have the benefit of knowing it is true. On the other hand, if it is not true, we are better off knowing that as well.
Although Dennett's stated aim is to inspire a properly scientific investigation of religion rather than carry one out himself, he does offer some initial speculations suggested by the work of pioneering anthropologists such as Pascal Boyer and Scott Atran. Religion, he claims, probably has its origin in several interwoven threads of our evolutionary history. One is the problem of recognizing other agents, rooted in the tendency of the human mind to ask, "Who's there?" when we encounter something that startles or frightens us. Another is what he calls the "sweet tooth" hypothesis, that religion is a natural source of hyperstimulation of some module in our brains that originally evolved for a different reason (similar to the human sweet tooth for fat and sugar). He suggests that this module may be susceptibility to hypnosis, a potentially important trait in the ages before modern medicine, as it would help wounded or ill members of the tribe derive benefit from shamanic healing rituals that would encourage the body's own powers of self-healing through the placebo effect. Finally, there is the memetic explanation: some religious beliefs may replicate because doing so is advantageous to the beliefs themselves, not necessarily because they confer any survival advantage on the people in whose heads they reside. (Although they can. Just as with symbiotic relationships in nature, a meme can be a mutualist, benefiting both itself and its host, a commensal benefiting itself without affecting its host, or a parasite benefiting itself to the detriment of its host. Dennett considers all of these possibilities, and others as well.)
All these traits and others combine to initially create what Dennett calls folk religion, the corpus of supernatural beliefs that are widely accepted in a society without being recognized or treated as a religion as such; they are just part of what "everybody knows". He offers some hypotheses on how these folk religions develop over time into the complex and organized canons of true religion, drawing a parallel with the way folk music gave rise to professional, organized music through a process of reflective elaboration.
Finally, Dennett considers the relation between morality and religion. He argues that views backed only by faith and not by reason have no legitimate place in the social discussion of morality, and that a person who relies solely on the authority of their sacred text when debating people who do not accept that text as authoritative has in effect excused themselves from the conversation. Regardless of whether God has actually spoken to them or not, he says, if they cannot support their convictions to others then they should not expect to be taken seriously. He also suggests, following the thesis of other authors such as Sam Harris, that the moderates in each religion should take steps to condemn and curtail the activities of the violent fanatics that give all religion a bad name.
In his closing arguments, Dennett suggests some testable avenues for future research into religion. On the basis of his efforts so far, he does make one definite policy recommendation: we should teach, in schools and other areas, "about all the world's religions, in a matter-of-fact, historically and biologically informed way" (p.327). Doing so, he says, will combat the sort of dogmatism that leads to religious warfare and hatred and enable people everywhere to make a truly informed choice. "[T]he devout of all faiths should face the challenge of making sure their creed is worthy enough, attractive and plausible and meaningful enough, to withstand the temptations of its competitors. If you have to hoodwink - or blindfold - your children to ensure that they confirm their faith when they are adults, your faith ought to go extinct" (p.328).
Although I enjoyed this book, as I enjoy all of Dennett's writing, I got the sense that I was not its target audience. Dennett says as much himself: his major purpose in writing it was not to reach atheists who probably already agree with him, but to reach theists and encourage them to think critically. As I am not a theist, I am not qualified to offer advice on how likely it will be to succeed at this goal. However, I can find no fault in either his reasoning or his conclusions.