In what ways does Piggy prove himself superior to Ralph in Lord of the Flies by William Golding?

More adult in appearance, Piggy represents the more rational aspect of humans in William Golding's allegory, Lord of the Flies. In fact, at one point, Ralph even reflects that "Piggy could think" and rues that he is not as capable as his friend at doing so.  One example of Piggy's clear thinking is after Jack and the hunters steal the fire.  Most disconcerted at the loss of the one thing which can reconnect them to civilization, Ralph becomes anxious that they are not able to climb the mountain to reclaim the signal fire.  But, in Chapter 8 Piggy suggests that Ralph and he and the others with them rebuild the fire on the beach:

The boys began to babble. Only Piggy could have the intellectual daring to suggest moving the fire from the mountain.

Allegorically, however, Piggy's glasses respresent his ability to reason.  So, after these glasses are stolen by Jack, Piggy loses some of his clear-sightedness and becomes emotionally myopic as well as physically.  For instance, he denies the facts about Simon's death.