Edit: Note that this is not about whether scientists can or do believe in God in some form, nor whether the supernatural actually exists.

The scientific method is an empirical and measurable body of techniques for investigating natural phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.

Its methodology relies on the fact that all phenomena in our universe originate from natural forces. That is to say, they follow certain rules or laws that categorize the structure of everything we see, such as the various laws of physics. Some laws and theories about the natural universe are underdeveloped, and we still have much to learn or discover, but nonetheless we are still here positing that everything that can be discovered will arise from the natural laws of the universe.

Supernatural intervention, such as a God or spiritual entity who can affect the course of life (notably for humans) runs contrary to the belief that everything occurs due to natural forces, the belief that distinguishes the scientific method. If events or phenomena can arise from a source that is not a natural law of the universe or does not follow these natural laws - in short, if miracles can occur (especially miracles that directly contradict known laws of physics) - then the premise of scientific inquiry is flawed. But, if the premise of scientific inquiry is not flawed, then there can be no supernatural forces.

This is not to say that no spiritual figure, such as a God, is compatible with science. One could posit that such a being began the universe or set the event known as the Big Bang in motion, and has since been dormant or cannot intervene in the natural universe. This is only to ask if there is any way an intervening God, particularly one who "watches over us" can co-exist in the mind of someone who also believes in the accuracy and trustworthiness of scientific pursuits at large.