An omen is nature favoring us with a remarkable event, the glow from which makes our life different for a while. The fact that a mechanical explanation can be found does not mean its the only one, nor does it cease to be the work of some larger and more encompassing form simply because the tools it uses can be understood.To me this holds a bit of the answer to the tension between the spiritual world an science. I tend to favor the scientist, but am keenly aware that a scientist leans heavily on what they feel they already know. This can turn into persecution and ridicule when something accepted as fact is challenged. It also pulls weight for the spiritual side saying there is no reason the super natural can't use tools that are known (or mechanical). Also interesting is the temporary glow from an omen. I think this temporary-ness is why Christians are encouraged to not trust emotions, though more often I interpret it as not wanting us to think to much about it and not trust what our minds and bodies tell us is right, what feels right.
Passing unobserved is indistinguishable in practical terms from being invisible.
We practiced every technique, but it was not until we learned to blend in mentally with the woods that we became as good as invisible.Only when we are mentally in tune with nature and the world around us do we blend in. This says a lot about the power of our mind. If we don't let our minds truly engage with what we are focusing on we aren't at full capacity. It kind of goes along with
What ever you find to do, do it with all your heart.