Sorry I forgot you, Klax! I should have written “Nobody else here … except Klax … claims such certitude.”
You want to rescue John - but fail to see your own very self in his words. What everybody else sees in it all is: “I’m finished with learning anything - and have decided that as the smartest one in the room, there is nothing left for me to do but teach everyone else.” That’s what certitude has come to reveal (at least in the U.S. here these days). There must be a place for teachers, of course - and sometimes a person might actually be the needed one with some given audience. But there is something essential about making that discernment freshly for each new context a person enters into. When one comes into each setting mouth first (rather than ears first), all their stated certitudes are rightly doubted, since the source is recognized as unable to have engaged sufficiently as a learner. The actual veracity of such certitudes may or may not be there of course - but even the ones that may happen to be true (any of us can get lucky - or better yet: make wise choices about who we listen to) will probably be more ably demonstrated by others who show signs of actually having engaged with the associated challenges. In other words, one person’s certainty is not necessarily equal (or as valuable as) another’s in regard to public persuasion - even if the proposition itself is, in the end, true.
[If you want to get some initial sense of who the actual one is in any context that you probably ought to be listening to, look for the trademark humility. Not a foolproof plan, of course, but one could do worse. Steve Shaffner would probably have the most claim to being one of the smartest ones here (in this particular area of discussion), and his words tend to have the most caveats, give-and-take, limiting himself to the solid data such as it is … in other words - the attendant humility of a life-long learner. Not afraid to express certitude where he has it, but not exploding with them in all directions beyond what he can support.]