(quote from RealReality.org/Real_Faith_and_Reason_Vol_3_-_Scientia.pdf)

If we don’t have the truth, we’re subsisting in a world of illusion and delusion. Unless reasoning BEGINS with truth, reasoning can’t lead to truth. Sound reasoning must always be based on truth. We can’t base reason on untruth or we deceive ourselves regardless of how well the untruth is presented. The more convincingly a persuader presents an untruth, the more hurtful and dangerous the lie

(end quote)