Failed to get "to map onto reality"

Does it mean "to exactly reflect the reality"?

Context:

Even having an immaterial
soul as many suppose, Harris
notes, would not give us free will:
“The unconscious operation of a
soul would grant you no more freedom
than the unconscious physiology
of your brain does.” He thus
concludes: “We are not the authors
of our thoughts and actions in the
way people suppose… The idea
that we, as conscious beings, are
deeply responsible for the character of our mental lives and
subsequent behavior is simply impossible to map onto reality.”

MOre:
http://www.colorado.edu/philosophy/vstenger/FreeWillSkeptic.pdf