I am working on a book where I will propose an alternative to the almost universally accepted concept of total depravity and its relationship to original sin; I do not believe that to be the case at all. I believe when God put Adam out of the garden, Adam lost his right standing with God and every person born shares this plight and so every decision we make falls short of the glory of God and that is the basis of our sin nature. So in this manner it is absolutely true that in Adam all sin because we are all born outside of God’s perpetual presence, which is the essence of His glory and until that right relationship is restored we are enslaved to a sin nature no matter how ethically, morally good our decisions may or may not be.
This is why I believe the incarnation and the indwelling are so vitally important… for oftentimes the remedy says more about the malady than we give it credit. The indwelling restores right standing before God and that is what Jesus went to the cross to accomplish for those who will “look up and live.” (Numbers 21:8-9)
This is the simplicity of soteriology as I see it.