Brigham teaches that "Mormonism" embraces all truth from all sources, both from revelation and from secular sources.
Brigham young, "Building the Temple—Mormonism Emrbraces All Truth," April 8, 1867, Journal of Discourses, 26 vols. (Liverpool: B. Young, Jun., 1867), 11:375
“Mormonism,” so-called, embraces every principle pertaining to life and salvation, for time and eternity. No matter who has it. If the infidel has got truth it belongs to “Mormonism.” The truth and sound doctrine possessed by the sectarian world, and they have a great deal, all belong to this Church. As for their morality, many of them are, morally, just as good as we are. All that is good, lovely, and praiseworthy belongs to this Church and Kingdom. “Mormonism” includes all truth. There is no truth but what belongs to the Gospel. It is life, eternal life; it is bliss; it is the fulness of all things in the gods and in the eternities of the gods.