Most Christians have always thought that at the Fall we fell comprehensively, though many don’t like the category of “total depravity.” But, as Cornelius Plantinga put it in his brilliant Not the Way It’s Supposed to Be, is there any doctrine more demonstrable by experience? Isn’t our messed-upness clear to each of us?
Maybe this will help us think of it anew: death itself shows that our bodies are broken and decaying and fallen; WW2 and Vietnam and international strife and international terrorism and family abuse and petty jealousies show that there is something cracked in the heart of humans; and does not the postmodernist push that even our knowledge is limited by who we are and where we are and what we ask evidence that even the mind is fallen?
Death reveals us our mortality, wars our distorted yearnings, and postmodernism our mental limitations.