What role does Mercerism play in the life of a bountyhunter?

Mercerism is the novel's main religion; a religion in which humanity fuses with the suffering character of Mercer in order to gain a greater sense of collective empathy. Dick seems to say, the values of Mercerism - namely, shared empathy and the collective will to survive - have transcended any notion of whether the religion's symbols are false or not. This speaks to humanity's deep need for the spiritual. This need, and the manifestation of this need, has made Mercer real in a way that the androids and Buster Friendly cannot truly understand. Rick's fusion with Mercer in the novel's closing chapters shows how the values of religion can become important for the collective of humanity.