The Nature Of Spirit

I have made an extensive search regarding what others think about the nature of spirit, but I have found absolutely nothing that satisfies me, nothing that answers my question, "What is Spirit?". Of course I don't deny that most definitions given are acceptable, but they are neither conclusive nor complete. They don't include everything. Philosophers might say that spirit is the vital force that keeps us alive. Fine. Religious people say that it is the divine spark inside each of us, in other words the soul created by God. Fine. Most scientists seem not to acknowledge the existence of such possibility. They say that you need "proofs". Rather difficult, isn't it? Others say that all things, even thoughts, are  things. Fine. I accept the definition of thoughts as the building blocks of the way we arrange our lives. (Positive Thinking affirms it). But spirit is something else. Keeping us alive might be one of its "functions" (and it most certainly is), but I believe that there is more to it. You may say spirit includes the idea of feelings as well, and you could be right. As far as I am concerned, all I have been doing, so far, is becoming aware of my eagerness to know and understand more. I acknowledge my desire to make the quantum leap in the hope of  finally reaching a satisfying answer, of guessing what I unconsciously know is there but that I cant't reach with my mind. Oh, yes! The problem is all in this word, mind. In fact our mind (the only tool we have at our disposal) always wonders, asks, reasons, looks for answers, makes hypothesis. But the nature of the spirit is totally beyond its reach. Has this reasoning of mine reached any conclusions? Absolutely not. The only outcome I can come up with is the idea that spirit cannot be grasped, much less understood. Are you disappointed? So am I. Any ideas? Please share. Is this destined to be a never-ending quest? Or, even worse, a question without a reachable  answer?