I hear about these individuals so frequently, it pains me. It has nothing to do with the fact that someone can actually be both theistic and understand the actual scientific status of evolution. Several very prominant scientists are theistic evolutionists. Ken Miller comes to mind. What does pain me is that such individuals are theistic. As someone who has gone through the transition (at the age of about 10) from being complete theist to a moderately strong atheist, I find it unusual that one can continue to believe in invisible beings. This is not limited to gods, but also includes angels, souls, spirits, and so forth. The idea that our complete conscience is a product of the interactions of millions of cells far surpasses, in terms of splendor, that some magical spirit pulls the strings our body like a puppet master.
Theistic evolution is the compartmentalization of two world views. On the one hand, the individual understands that this god (or gods) was (were) not necessary for the development of life on Earth (through evolution) and yet continues to believe this entity (or entities) are the terminator to the infinite regress. As Thomas Aquinas puts it, the “unmoved mover” of the universe. This is where the problem begins.
There is no reason to assign a terminator to this infinite regress for, as we shall see, it is not warranted, at least in biology. The various models of abiogenesis including the “Genes first” (RNA world) and “Metabolism first” (iron-sulfur world) models provide a gradient by which no terminator is necessary. Whether we can know, beyond any doubt, which model is correct is another matter. There are numerous possible models by which life may have originated on this planet without the intervention of any deity.
Numerous theological loopholes are used such as the “the Bible is inspired by God written in metaphor to fit into human language” or similar arguments. Allow me to explain how vaccuous an argument this is. When the New Testament was written, less than 2,000 years ago, Ovid had already written his Metamorphoses, the Homeric epics were written long before that. Leucippus had written much on atomism. Couldn’t we at least get a decent approximation for pi? (1 Kings 7:23) How about some decent natural history? (Matthew 13:31; Mark 9:44-48) Is it too much to ask for a bit of decent medical advice? (Luke 13:11; 2 Chronicles 16:12) That’s one inspirational omnipotent and omniscient being.
Not only were the passages I mentioned blatantly incorrect, some are actually quite dangerous (2 Chronicles, for example). The fundamental issue is not that “one can believe in god and evolution,” but rather “how can one believe in god at all?” Watering down cosmological, natural, and human history to suit your unfounded religious beliefs takes more away from the splendor of these histories than could ever be gained by theology. Why do I take issue with the blending of theology and biology?
Now that I have every single theistic individual quite upset with me, allow me to mend some of these wounds. While it is my opinion your religion is a flawed worldview which is based upon a great many baseless assumptions, I will not exclude your importance to scientific discourse on these grounds. You may approach many research fields with additional insights. It is also possible (and frequently done) to segregate the theology of one’s religion from the scientific knowledge of one’s field of expertise. What troubles me are the quotations such as “God constructed the universe in such a way that the appearance of life was not only possible, but inevitable.” This puts teleology into evolution. This is where I take issue.
Believe whatever it is you wish to believe, “babies are filled with gold.” I could not care any less. My problem is when one assigns teleology or directionality to non-directional processes. For illustration of the directionless nature of evolution, look at Lenski’s research. Better yet, look at every organism around you. Every organism evolved through a non-teleological process of evolution. These were not designed, nor were they some ultimate product of the evolutionary process. They are evolving and will continue doing so long after the human species has vanished from this planet. Observe the natural splendor on this planet, look closely enough and you shall see, not any deity or spirit, but a hint of yourself, tied into each and every organism.