Read it through once

The misguided imaginations of men have rendered the ascertaining of what IS NOT TRUE, the principal direct service which metaphysical science can bestow upon moral science. Moral science itself is the doctrine of the voluntary actions of man, as a sentient and social being. These actions depend on the thoughts in his mind. But there is a mass of popular opinion, from which the most enlightened persons are seldom wholly free, into the truth or falsehood of which it is incumbent on us to inquire, before we can arrive at any firm conclusions as to the conduct which we ought to pursue in the regulation of our own minds, or towards our fellow beings; or before we can ascertain the elementary laws, according to which these thoughts, from which these actions flow, are originally combined.