Recent progress in neurotechnology is providing redemptive hope for many people who suffer from the limitations of physical disabilities, promising that one day soon the “blind will see, the lame will walk, and the deaf will hear.” But technological progress has also led to eschatological prophecies which envision technology as profoundly impacting the nature of embodied human existence. How are we to understand and evaluate such proposals? In our pluralistic culture, discourse in the public square over biotechnological issues is acceptable only if publicly accessible secular arguments are utilized--and so we strive to remove religious language—and teleology--from our discourse, but such elimination is not always desirable. Transhumanists have sought to eliminate teleology from human nature only to replace it with a teleology of their own choosing; and teleological propositions can only effectively be countered by alternative teleological perspectives. This paper explores four perspectives on the nature of human existence (substance dualism, emergent dualism, non-reductive physicalism, and material constitutionalism) with attention to their ability to set moral limits on biotechnological enhancement. Only a Christian teleological perspective can provide the necessary moral boundaries.