“[T]his progress of the physical sciences, which the passions and interest do not interfere to disturb; wherein it is not thought that birth, profession, or appointment have given a right to judge what the individual is not in a situation to understand; this more certain progress cannot be observed, unless enlightened men shall search in the other sciences to bring them continually together. This progress at every step exhibits the model they ought to follow; according to which they may form a judgment of their own efforts, ascertain the false steps they may have taken, preserve themselves from pyrrhonism as well as credulity, and from a blind mistrust or too extensive submission to the authorities even of men of reputation and knowledge.”