One of the biggest aspects of my mental awakening has been my realisation that as the capabilities of science has increased so the need for essentially "woo" explainations for things not understood has decreased.
The inability of science to currently reanimate dead things does not mean there has to be a supernatural force at work keeping things alive. It simply means that science cannot monitor and control the sub-atomic bio-chemical processes that are taking place. I am sure that at some point these processes shall be measurable.
There are many things that are beyond the ability of scientists to measure or observe at the current time. What they are able to do however, is predict what the nature of these things may be. There will be things that they know nothing about right now and cannot even predict the existence of but, as science advances, so too will the realisation that these aspects of the universe exist.
My personal opinion is that the "spirit" world does not exist so there is little sense trying to define what the nature of a spirit being is.
For the sake of argument, however, I am sure that if there were such a thing then it's nature could be, at some point in time, measured and observed. At the very least, it's nature could be predicted and explained using mathematics, physics, chemisty and biology.
Any other conclusion is simply a variation on the "it wos God wot dun it" theme.
