So we should avoid teaching about black holes, dark energy, anti-matter, and quantum physics? Because these are also things that we can't make useful predictions, test, or independently verify. From a biological standpoint, your imagination can not be proven to physically exist, does that mean it doesn't? e=mc2 doesn't seem to apply to worm holes, does that mean we should stop teaching it?
You're right, the existence of a spiritual being is beyond the capacities of Biology, so there is little you can do with it. However, a biologist has to recognize the results of independently verified tests and predictions. In every species of life we have ever studied, inherent behavior is defined by fundamental purpose, and this does not waiver. No living thing does something inherently, without a fundamental purpose. It's been tested over and over, with millions of living things, it has been verified and confirmed independently by thousands of peer reviews. Human beings have the propensity to worship a supreme power or spiritual entity. They have had this apparent trait for as long as we can find remains of human civilizations. It is something we are inherently drawn to as humans, and while it has taken many forms, it has not diminished over time, as a fundamental human behavior. How can a biologist explain this, without supposing the inherent behavior serves a fundamental purpose in function? To deny that, is to defy everything we understand about the scientific methodology and biology.