Hey BB, these are excellent questions. and speaking as one who was (and is) fiercely resistant to anything not backed up with experiential data, I have spent a long time trying to reconcile my intellectual understanding of spiritual phenomena, with my direct experiences. I still haven't got a perfect answer yet, but I have a few really good ideas, I have adopted, which help me grasp the idea of "soul", and so far they've stood up fairly well, I think, so I will try to give my interpretations of the phenomena of which you are speaking, in your questions:
(1)Can a soul think without a brain?-- souls don't "think" in the conventional way we do. souls are the divine spark which enable us to think at all, so you could say a soul is the source of thought itself. soul is also, in another way, the individual's link to the Universal Mind, so rather than being a thing that can be measured, its really a dimension of selfhood. Forgetting the soul when considering a person would be like building a house with only width and height. It looks pretty from the front, but there's no room to live inside.
(2)can a soul speak without a mouth? ---souls communicate through intent. I believe the soul is the source for all thought/emotions/drives, etc. so you cannot "hear" a soul speaking to you with your "ears", you can only sense its communicating with you through your own soul. The way I have experienced it, is like that rising feeling you get right before an idea strikes you, when it hasnt formed entirely but you can feel it coming on. that subtle feeling right there is what it feels like when a spirit (or soul) is talking to you. you have to still your mind quite a bit to hear it, but it can be done.
(3)can there be anything at the spot where a soul is?--I think you are asking if the soul has extension, can be measured physically, and the answer is no, not really. if it has any physical aspect at all, its as a subtle vibration, which may be (i believe) smaller that the smallest sub-subatomic particle. Its vibrating so fast though that it has an energetic presence in space, and we can feel it--but only though our own souls. maybe souls all operate in the same frequency range, is why? I dont know, thats just a guess.
(4) is it possible to build a machine to spot a soul?---I dont think so, but you never know. Maybe as string theory starts being better understood, and science starts to examine all the subtle stirrings in space around us, and not just focusing on the big, planet-sized things moving around,..maybe? but who knows! :angel2: