Ralph is badly shaken by Simon's death whilst Piggy is in denial. Piggy is able to be of some comfort to Ralph at this time but only by playing down Simon's death and insisting that they had done nothing wrong.
Ralph views Simon's death in its most sinister form - murder, and the implications of that cause a near nervous breakdown, "I'm frightened. Of us. I want to go home. O God I want to go home" (p. 194). He manages to get past this point by submitting to Piggy's pleas that it was only an accident and they weren't directly involved.
Piggy would clearly have been just as happy to have never talked about Simon's death, but when pushed by Ralph he insists that it was only an accident. He is also determined to shift the blame; firstly it was because of "that bloody dance" (p. 193) and then he claimed Simon it was Simon's fault, "He deserved it. He was batty" (p. 194), and finally by implication it was those boys on the inside of the dance who were responsible.
Simon's death is the shocking climax to the novel, and we see the main characters (including Jack) react in diferent ways to the events of that evening.