Are the Gods real? This is simply not an important question. A horror movie, no matter how fake, can still make your skin crawl.
As a teacher of internal martial arts and qigong I often give instructions to students which they find incredible. For instance I might say, "Move your skin up but your body down." Or I might say, "Spiral the bones inside the tissue." Sometimes I'll describe a feeling outside of the body, as if the we were moving in water or mist. People often ask me, "Should I visualize what you are telling me?" Or, "Should I just try to imagine what you are telling me? because I don't know how to do that."
What will "work" for the student at this point varies a lot from student to student. Sometimes it helps if I have a student put their hands on me while I do the movement. Some students will learn by watching closely. Some students will simply figure it out with time. Some students will require a different exercise, or a different description, or a different metaphor, or a different context, or a different type of pickle in their porridge (yes, I do make these sorts of suggestions). Some may even get it and not realize they have gotten it.
But the answer to the question, "Should I visualize? should I imagine?" is simple. Yes, you should imagine to the exact extent that imagining actually makes your skin crawl. We tend to think, in our "agency driven universe," that imagination is not real. Imagination is real. No movement happens without imagination.
Here are two posts I wrote in 2007 which deal with this question as philosophy and cosmology:
Understanding Chinese Culture (Part 1)
Understanding Chinese Culture (Part 2)