A conceptualist argument for a spiritual substantial soul

I advance a type of conceptualist argument for substance dualism - minimally, the view that we are spiritual substances that have bodies - based on the understandability of what it would be for something to be a spirit, e.g. what it would be for God to be a spirit. After presenting the argument formally, I clarify and defend its various premises with a special focus on what I take to be the most controversial one, namely, if thinking (i.e. conscious) matter is metaphysically possible, it is not the case that we have a distinct positive concept of God's being a divine spirit.