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.
At the beginning of Chapter 10, Ralph tells Piggy that they murdered Simon. Piggy realizes that they savagely killed Simon, but attempts to repress the memory and not speak about it. Ralph takes responsibility for participating in Simon's murder, while Piggy begins to make excuses for their actions. Piggy mentions that they were scared, and Simon's death was an accident. Piggy tries to end the conversation by telling Ralph that it won't do any good by continuing to talk about it, but Ralph says that he's frightened. Ralph realizes the extent of savagery on the island and is appalled that he partook in Simon's murder. Ralph begins to fear for his own safety while Piggy attempts to forget about the whole ordeal. Both boys feel guilty; however, Ralph acknowledges his participation while Piggy denies his involvement.