> I can see that by the time I retire, the knowledge I have spent my adult life acquiring will be useless historical trivia. It's depressing. Is that so bad? I

> I can see that by the time I retire, the knowledge I have spent my adult life acquiring will be useless historical trivia. It's depressing. Is that so bad? I expect the more important thing are the results that the learning allowed you to render. If the knowledge has a half-life but you contributed to or built something meaningful that endures, isn't that what matters? The knowledge and skills are like the scaffolding that allow you to arrive at a certain height or build something of value. And at the end they can be taken away and you're left with the fruits. Unless, of course, your intention is to have knowledge that you can pass on to future generations via writing/training.