Summa Theologica

“Endeavoring to avoid these and other like faults, we shall try, with confidence in the help of God, to set forth whatever is included in sacred doctrine as briefly and clearly as the matter itself may allow.” 

A mission statement for the Summa. Aquinas declares that his book will avoid the faults of previous theology manuals, including an arbitrary structure and “frequent repetition” that brings “weariness and confusion” to the reader. The quote underlines the lucid, clarifying intentions of Aquinas’ work, as well as the fact that it is aimed at beginners.

“It was necessary for man’s salvation that there should be a knowledge revealed by God, besides the philosophical sciences built up by human reason.” 

A clear expression of Aquinas’ belief in the complementarity of reason and faith. Faith, or revelation, perfects and builds upon reason and sense knowledge.

“The knowledge of God is naturally implanted in all.”

From Damascene. Aquinas goes on to clarify that we all have a “general and confused” perception of God’s existence, since this is necessary in order to set us on the path to seeking God as our ultimate happiness. However, to gain more clarity on the existence of God we must follow a reasoned argument. Aquinas therefore presents his Five Ways.