The Age of Reason by Thomas Paine - Part 2, Chapter 3

"The study of theology as it stands in Christian churches, is the study of nothing; it is founded on nothing; it rests on no principles; it proceeds by no authorities; it has no data; it can demonstrate nothing; and admits of no conclusion. Not any thing can be studied as a science without our being in possession of the principles upon which it is founded; and as this is not the case with Christian theology, it is therefore the study of nothing." [A harsh rebuke of Christianity]

"[if a] revolution in the system of religion takes place, every preacher ought to be a philosopher. Most certainly, and every house of devotion a school of science." [Replacing religion with philosophy and science]