He points out that the structure of knowledge must be constantly refined. Basic science tells us that you cannot see without using your eyes. If you say that your hands can read, then why can't the blind employ this method to restore their sight?
他指出，知識的建構必須經過千錘百鍊，以科學常識論斷，不用眼睛自然無法看到東西，如果硬說手能識字，那靠著這種方法，盲人是否也可以「復明」？