In the west, the ideological war between science and religion grew until Descartes proposed the truce of dualism based on “I think, therefore I am”. Why not have mind and body, the spirituality of religion and the physicality of science? This divided scientists into atheists who believed only in the physical world, theists who believed in a world beyond it as well, and agnostics who couldn’t decide. This marriage of convenience worked for a while but today science and religion barely speak to each other.
The dualism problem is how can two distinct realities co-exist? If mind and body don’t interact they are irrelevant to each other, as what use is a mind that can’t affect the body? Or if they interact, which came first? A mind that emerges from a physical brain is like the whistle of a locomotive that is superfluous to the main action, while if a non-physical mind creates the world, why is it such a mess? Either way, if one is real then the other isn’t, or at best irrelevant. And if the two realities are in conflict, why hasn’t heaven purged earth already or earth corrupted heaven? If mind and body are sides of the same coin, what is the coin?
Facing such challenges, dualism is currently in retreat before the monism that there is only one reality and it is physical. Monism is simpler than dualism and the main monism today is physical realism. While scientists claim the physical world they study is real, theologians claim that a future spiritual world is real, and people in general prefer now to later.