Posing this question to myself:
What would it do to my theology if I drew a simple equivalence between the religious concepts of Body and Spirit, and the scientific concepts of mass and energy?
Not so much to work out complicated equations, but to admit the descriptive commonalities between the pairs, in the light of contemporary science?
Body and mass are both about substance (thinking of the creation of a clay Earth, and humanity out of that clay, for example), whereas Spirit and energy are about movement and change (thinking of the dynamism of motivated dust, either blown by the spirit 'where it will', or, stepping up a level, descriptive of those attributes of humankind that, in the opinion of biblical writers, separate us from the animals).
The difference between scientific and biblical accounts being that we have now framed the concept of evolution, allowing us to see that the progression from dust to animals, and animals to humanity, is one of complexity, a result of the interaction between mass and energy over the lifetime of the universe, rather than one of fundamental ontology.
My problem with the comparison? I suspect its simplicity, and that, as like as not, is a result of my upbringing in a society where religion and science have been held separate, both by scientists and church people. My fear is, I think, one of category error - a muddying of the waters, the risk of foolishness. Studies of fundamentalism point to disgust as its defining emotion, which is thought to have evolved to enable us to avoid the kind of contamination that results from tainted water and food sources, and might put our survival at risk. It's hard, in this case, to shake the feeling that I'm slipping into an ill-thought-out pseudoscience, neither fishy coelecanth nor trickster coyote in a crow mask.
But the links I've drawn are observational, and in that sense, uncontroversial. They are not making a metaphysical case for an untestable substance (spirit in its popular, separate-from-natural sense, such that one might say there is mass, and energy, and spirit as well), neither discounting the existence of a motivating force behind, or even in the nature of it all (Love as I have understood it/her/him [must return to this!]). All they do is challenge (whilst affirming) a dualism, the way Einstein challenged and affirmed it in his famous equation.
[Written in the wee small hours. There's something to be said about what one experiences in altered states of consciousness - such as dreams - and how these relate to tangible reality. My inclination is to say that describing the 'journeys' one takes in these states as being through the spirit world - as I have sometimes thought - is not absolutely helpful.]