Irony in On Evolution

I thought it was ironic when Darwin admitted " This Abstract, which I now publish, must necessarily be imperfect. I cannot give references and authorities for my several statements; and I must trust to the reader reposing some confidence in my accuracy." His theory is claimed by many to disprove the existence of a god or divine being that people have no proof of but have faith in. Ironically, He is asking the reader to have faith that his calculations and theories are true. Science is supposed to be absolute and be precise. We don't have faith in laws and theories; they are proven by trial and error to be true.