You absolutely can measure, to some degree, the internal state of somebody’s brain (what you call “Soul”). Is the person happy or trying to commit suicide? Now

You absolutely can measure, to some degree, the internal state of somebody’s brain (what you call “Soul”). Is the person happy or trying to commit suicide? Now there is one very rough measure of somebody’s internal brain state. Is the person constantly punishing him/herself? Now there is another. Is the person a sociopath? Another one. The last one can even be measure using a brain scanner. No need for human interpretation there. I assume you are religious (using words like “Soul”) so perhaps remember Jesus saying “You will know them by their fruit”. In other words, you can measure their “Soul” by what they do.