It was all for power

I've listened to people give massive quantities of erroneous information and say it with such assurance and complete authority, that it not only is believable, it becomes fact of the matter. Of course it's said with the seriousness and gravity of an expert, and sometimes it's shared as an aside, or let me let you in on the real thing, this little secret of why and what for. I know that the people sharing it begin to believe in all earnestness that what they say is true and the recipients are so grateful for the imparting, that the lie becomes as valuable and weighty as the truth could have ever been. It's astonishing, nothing less, and it happens every day, in tons of settings, not just in the library where it would be nice to only hear or see people telling the truth.