One could equally retort:
What we're being asked to consider is that if you damage the lenses in your spectacles in one way so as to result in a deterioration of your vision, you damage them in another way resulting in yet further deterioration of one's vision, and yet if the spectacles suddenly disintegrated our vision would be fully restored?? You silly irrational people!
Also see this post and a more expanded version here in my other blog.
