They can "sense" the supernatural.

Imagine if you always knew which direction was magnetic north. It's just automatic. When you think about it, you just point in its direction. No problem. Or, you kind of have to concentrate on figuring it out but when you do, you totally get it.

That's kind of what it's like for the common gifted. They "sense" that there's essence, they can feel it in their environment. When something like a spirit is nearby, they should have a chance to notice its presence. But it's basically a secondary sense to them. Kind of like how our sense of smell is a joke compared to most animals. We can smell stuff, sure, and can get some ideas or even process in deep brain capacities but we don't gather quite the same kind of information a cat, dog, or vulture would.

Fortunately, in the world of Armageddon and WitchCraft, there are "skills" and specific beings that can sense essence with that degree of precision and accuracy. Imagine a spirit and how it totally senses the entire world around it strictly in terms of how essence moves. It would be kind of like sensing electric fields and their influences on you and the world as well as hearing or smelling it. But a spirit trying to explain that in English would not have the words because, frankly, that's not a thing in the real world. That's why we rely on generic words like "sense" or "feel" even though we don't mean touch.

It's a good topic of exploration, one that is easily written off as "seeing" and "gut feeling." I think I got your question and I might get a chance to elaborate later.

Clarity of purpose. Clarity of conscience.