Nicene and Post-Nicene Fathers: Series I/Volume II/On Christian Doctrine/Book II/Chapter 34

Chapter 34.—It is One Thing to Know the Laws of Inference, Another to Know the Truth of Opinions.

52.&#160; Therefore it is one thing to know the laws of inference, and another to know the truth of opinions.&#160; In the former case we learn what is consequent, what is inconsequent, and what is incompatible.&#160; An example of a consequent is, “If he is an orator, he is a man;” of an inconsequent, “If he is a man, he is an orator;” of an incompatible, “If he is a man, he is a quadruped.”&#160; In these instances we judge of the connection.&#160; In regard to the truth of opinions, however, we must consider propositions as they stand by themselves, and not in their connection with one another; but when propositions that we are not sure about are joined by a valid inference to propositions that are true and certain, they themselves, too, necessarily become certain.&#160; Now some, when they have ascertained the validity of the inference, plume themselves as if this involved also the truth of the propositions.&#160; Many, again, who hold the true opinions have an unfounded contempt for themselves, because they are ignorant of the laws of inference; whereas the man who knows that there is a resurrection of the dead is assuredly better than the man who only knows that it follows that if there is no resurrection of the dead, then is Christ not risen.