Cicero - The first duty is to distinguish truth from falsity, and to understand the relationship between one phenomenon and another and the causes and consequences of each one

From From A Noble Radiance by Donna Leon. Page 240.

Brunetti, finding himself with nothing to do for the first time in what seemed like weeks, decided to impose upon his books the order he was obviously incapable of imposing upon events and so went into the living room and stood in front of the ceiling-high bookcase. Years ago, there had been some distinction made according to language, but when that fell apart, he had attempted to impose the order of chronology. But the curiosity of the children had soon put an end to that, and so Petronius now stood next to St John Chrysostom, and Abelard sidled up to Emily Dickinson. He studied the ranked bindings, pulled down first one and then two more, and then another pair. But then just as suddenly, he lost all interest in the job, took all five books and jammed them indiscriminately in a space on the bottom shelf.

He pulled down his copy of Cicero's On the Good Life and turned to the section on duties, where Cicero writes of the divisions of moral goodness. 'The first is the ability to distinguish truth from falsity, and to understand the relationship between one phenomenon and another and the causes and consequences of each one. The second category is the ability to restrain the passions. And the third is to behave considerately and understanding in our associations with other people.'

He closed the book and slid it back into the place the vagaries and whims of the Brunetti family had assigned it John Donne to the right, Karl Marx to the left. To understand the relationship between one phenomenon and another and the causes and consequences of each one’ he said aloud, startling himself with the sound of his own voice. He went into the kitchen, wrote a note for Paola, and left the apartment, heading towards the Questura.