Take care to get information 

We live by information, not by sight. We exist by faith in others. The ear is the rear-gate of truth but the front-door of lies. The truth is generally seen, rarely heard; seldom she comes in elemental purity, especially from afar; there is always some admixture of the moods of those through whom she has passed. The passons tinge her with their colours wherever they touch her, sometimes favourably, sometimes the reverse. She always brings out the disposition, therefore receive her with caution from him that praises, with more caution form him that blames. Pay attention to the intention of the speaker; you should know beforehand on what footing he comes. Let reflection assay falsity and exaggeration.

Gracian, The Oracle, a Manual of the Art of Discretion