From a naturalistic point of view, all talk of good and bad spirits might be characterized as nonsense. Yet thinking about the explanatory value of spirits reveals that there is a significant difference between the idea of good spirits and bad spirits, and this difference is rather interesting.
As a form of explanation, naturalism provides highly creditable explanations for all the things that people once explained as caused by bad spirits – natural disasters, disease, and even our propensity to act badly. As for this last item, Darwinian evolution provides a comprehensive explanation for our sexual and gluttonous proclivities, selfishness, violence and aggression, and other “sins.” Indeed, the way our so-called “reptile brain” can thwart our best intentions, can seem very much like a kind of inner Satin leading us astray. There are some examples of human goodness that can be tied to Darwinian evolution, such as the mother’s care of the child. For the most part, though, these examples of goodness end at the boundary of the extended family.
On the other hand, that we do have “best intentions,” that we do have higher aspirations for our self and for our society, is not in any significant way explained by Darwinian evolution or by biology. These are largely cultural accomplishments. As just one example, we can follow the history of how humans have treated strangers. In many so-called primitive societies, a stranger could be killed without any kind of moral disturbance, and often were, unless they could provide something of value to the would be killers. In early civilization, we find moral injunctions to treat strangers with some kindness. Confucius taught that we should give our leftovers to the stranger. In Homer, there are even stronger ideas of how the stranger should be treated – which Odysseus often relies upon. And, there is Jesus’ parable of the Good Samaritan which suggests an even stronger moral obligation to the stranger. Cultures still struggle with treating the stranger or outsider well, but there has been improvement.
The idea of God as a moral and ethical ideal can help people both formulate their aspirations and inspire people to actualize them. As such, the idea of God can become a causative factor in the world. (Of course, the idea of God can also motivate people in destructive ways, particularly when the idea is used to serve in power struggles. The drive for power, though, is at base a biological motivation. )
Can naturalism inspire people to goodness? It is an interesting question, and much too complex to go into here. But I will conclude that while naturalism gives us good reason to get rid of the notion of negative spirits, it is not so clear that there are not negative repercussions in getting rid of the idea of positive spirits. We may need such “ethical muses” to inspire and energize our best intentions.