Above us, and all around us is invisible spirit. But how to comprehend it? Here is a train of thought to contemplate.

To make a ferment in a dough one sets the dough out and covers it. And Into it, like magic, comes the ferment. If one leaves it for a number of days, it will be unsavory, but if you take a little of the unsavory dough, and put it in a fresh dough, then the fresh dough is set out after it ferments again, it can then be baked and is a very tasty bread.
This is an invisible process of nature, and so the spirit to is invisible.
One needs to know how special the soul is to nature to begin the same process of transformation.