A theist could easily say there is a biochemical and theistic foundation for spiritual experience. They are not mutually exclusive.
Pixel42 said:
True, but the former makes the latter unnecessary.
Not really. There are two questions that arise when dealing with subjective spiritual experience:
how the experiences happen, and
why the experiences happen. A theist could be quite comfortable with the "how" explanation (neurological processes, etc.), but prefer the theistic explantion for "why" such experiences exist at all.
This also applies to cosmology. We have some idea now of
how the universe formed, but not
why there should be something rather than nothing. Or why a
highly improbable universe with life exists, rather than a much more probable lifeless universe consisting of just, say, hydrogren atoms. Again, theism could rationally be the preferred theory.
Finally, a theist could be completely satisfied with the scientific explanation for religious experience and still believe in a god because religion and science occupy two different domains. Or, as the National Academy of Sciences put it:
Science is not the only way of acquiring knowledge about ourselves and the world around us. Humans gain understanding in many other ways, such as through literature, the arts, philosophical reflection, and religious experience. Scientific knowledge may enrich aesthetic and moral perceptions, but these subjects extend beyond science's realm, which is to obtain a better understanding of the natural world.
Scientists, like many others, are touched with awe at the order and complexity of nature. Indeed, many scientists are deeply religious. But science and religion occupy two separate realms of human experience. Demanding that they be combined detracts from the glory of each.
Many religious persons, including many scientists, hold that God created the universe and the various processes driving physical and biological evolution and that these processes then resulted in the creation of galaxies, our solar system, and life on Earth. This belief, which sometimes is termed 'theistic evolution,' is not in disagreement with scientific explanations of evolution. Indeed, it reflects the remarkable and inspiring character of the physical universe revealed by cosmology, paleontology, molecular biology, and many other scientific disciplines."
http://map.gsfc.nasa.gov/site/faq.html
You arbitrarily favor materialism over immaterialism without any evidence for the former.
Pixel42 said:
Given the choice between
1. an explanation which fully explains a phenomenon without neeeding to postulate an entity for which there is no physical evidence, and
2. an explanation which offers no extra explanatory power but which does require such an entity
I favour (1), yes. That is not an arbitrary choice because (1) is the most parsimonious, and therefore the most rational, explanation.
No phenomena will ever be fully explained because we can never know what phenomena actually are. Is
seeing a result of photons striking our retina or a bit of code in a matrix or a part of an elaborate dream we're all sharing?
Again here, you assume a materialistic view of reality. What is this assumption based on? Evidence from your senses. What other evidence do you have? However, this sensory evidence is equally compatible with an infinite number of models of reality. To assume one model over another is simply a leap of faith. A theist could just as easily (rationally, you may say) assume her sensory evidence corresponds to an
idealisic reality. If reality is idealistic (everything is a projection of God's mind), then theism has is the more explanatory theory.
The assumption that reality is materialistic is so embedded in people here, many can't step back and see how it underpins their whole belief system about the world, and so they can't question it. It's like the old "here there be dragons" part of a map.
Pixel42 said:
For example, I do not believe that volcanic eruptions are caused by volcano gods but by hot magma being forced up from deep below the earth's surface by purely physical processes. You could point out that this and the volcano god explanation are not mutually exclusive because those physical processes could be the way the volcano god expresses his displeasure, and you would be right. But I do not consider that possibility sufficiently likely for it to be worth continuing to sacrifice the odd virgin to keep him sweet.
Do you believe volcanoes would continue to exist if all consciousness in the universe disappeared? If so, what is your evidence for this belief?