BOOK REVIEW - Key to the Science of Theology, Parley Pratt (1981)
Parley P. Pratt’s Key to the Science of Theology remains one of the most important early works articulating the intellectual and spiritual foundations of Latter-day Saint theology. Written in the mid-nineteenth century, the book reflects Pratt’s brilliance as both a preacher and philosopher, and it serves as an inspired attempt to systematize LDS doctrine in a way that harmonizes faith and reason.
At its heart, the book argues that theology is not an abstract or speculative pursuit but rather a true and universal science. For Pratt, religion and revelation are not opposed to reason but form part of the same divine order. He consistently emphasizes that true knowledge—whether gained through study, faith, or revelation—must be consistent with eternal laws established by God. This framing reflects a hallmark of Latter-day Saint thought: that the gospel is not only spiritual but also deeply rational, practical, and grounded in eternal principles, including science.
One of Pratt’s central themes is the universality of truth. He argues that the principles of the gospel encompass all truth, whether found in scripture, in nature, or in human reason. This expansive view allows him to portray Mormon theology as both ancient and modern, timeless and yet adapted to the progress of human understanding. In doing so, he sought to counter the idea that faith and science are opposed, instead presenting them as allies in the pursuit of divine knowledge. Which, to some degree was quite radical, for the period of the post Second Great Awakening when the book was published.
The book also touches on uniquely Latter-day Saint doctrines such as eternal progression, the premortal existence of souls, the potential of humanity to become like God, and the role of modern revelation. Pratt’s bold articulation of these ideas helped shape the confidence and distinctiveness of LDS theology. His message continues to resonate: that the restored gospel brings not only spiritual salvation but also a framework for understanding the cosmos, the destiny of humankind, and the eternal nature of truth.
Pratt’s work continues to inspire because it addresses a timeless concern—how to reconcile faith with intellect, and how to understand theology as a living science rather than a relic of the past. For Latter-day Saints, Key to the Science of Theology affirms that their faith is not irrational but rather a coherent, truth-seeking system that embraces revelation, reason, and moral progress.
Quotes:
“The science of theology is the science of all other sciences and useful arts—being in fact the only true philosophy—the only system of ethics—the only law—religion—and government—for it is founded on eternal truth. It is the fountain of light, of knowledge, of life, of immortality, and of eternal exaltation; while all other sciences combined are but ministers to this, the greatest of all sciences. They may, indeed, serve to adorn, to embellish, to supply temporal convenience, or to minister to the necessities of mortal man. But, without this science of theology, they would be as the body without the spirit, or as a world without a sun to give it light, life, or motion.”
“It is the province of theology to unite all systems of truth in one grand whole; to harmonize all discoveries in the heavens and upon the earth; to cement the creeds of nations into one great system of light and truth, from which will flow knowledge, life, power, glory, and eternal happiness. It is for this cause that God has spoken again in the last days, revealing from heaven those principles of truth, those keys of knowledge, those ordinances of power, and those revelations of eternity, which, gathering up the truths of all ages and all dispensations, will consummate the great system of salvation, and restore to man the dominion, the intelligence, and the immortality which he enjoyed before the fall.”