Conversations best had over beer

Remember my question about how well you could recreate your job ca. 300 years ago? I was discussing this in great and philosophical detail (after having drank about a bottle and a half of Three Philosophers brew between us), when my friend J pointed out,

As useless as what you know today would be 500 years ago, imagine how useless what you know will be 500 years from now. At best, you're a caveman.

It seemed a very insightful comment, and so I recreate it here. I suppose it's best just to be grateful we weren't born in a time where your life expectancy could be counted on one hand, in which iPods have been invented, and the danger of uncontrolled time travel is very small. Though, I'd keep an eye out for Blue Boxes all the same.