At its essence, Mercerism asserts that empathy is the definitive trait distinguishing humans. Pre-recorded emotional experiences, ranging from collective elation to profound sorrow, serve as litmus tests for humanity, drawing a stark line between authentic emotion and artificial mimicry. The protagonist, Rick Deckard, initially resistant to this emotional paradigm. The android Rachael Rosen, with her true-to-life human characteristics, intensifies Deckard's internal conflict, leading to the novel's central question: what truly defines humanity when machines can replicate our most cherished attributes?