Jack and Simon represent two different human approaches to the natural world. Where can I find evidence from the text?
Look no further than chapter 8. Jack sees nature as his for the taking. He establishes his authority in much the same way, smashing, stealing and manipulating. He treats nature in terms of what he can take from it. The incredibly violent death of the pig is motivated by Jack and Roger's bloodlust, and described in incredibly graphic detail.
"The spear moved forward inch by inch and the terrified squealing became a high-pitched scream. Then Jack found the throat and the hot blood spurted over his hands. The sow collapsed under them and they were heavy and fulfilled upon her."
Essentially, this scene is described not only in terms of killing, but in terms of rape as well. And that is how Jack approaches the natural world: his to own, control, and dominate.
Simon, on the other hand, approaches nature from a spiritual point of view.
Simon had passed through the area of fruit trees but today the littluns had been too busy with the fire on the beach and they had not pursued him there. He went on among the creepers until he reached the great mat that was woven by the open space and crawled inside. Beyond the screen of leaves the sunlight pelted down and the butterflies danced in the middle of their unending dance. He knelt down and the arrow of the sun fell on him. That other time the air had seemed to vibrate with heat; but now it threatened. Soon the sweat was running from his long coarse hair. He shifted restlessly but there was no avoiding the sun. Presently he was thirsty, and then very thirsty.
Simon prefers to enter nature as an individual, rather than with a mob. He sits in silence, contemplating what nature has to offer him as a gift, rather than what he can take. Ironically, Chapter 8 is entitled "Gift For the Darkness", implying that what Simon will find is evil rather than good, and horror rather than peace.