The concept of "youth culture," even when it referred to the culture of actually existing youths, has always been the result of adults looking back on their own pasts. It is, in other words, a back formation transposed forward, predicated on the assumption that to have been a youth once is all that it is required to understand a youth in the present. That mode of identification through recollection is the sine qua non of pedagogical theory as well. The threat posed by technological innovation is that it guarantees that successive generations grow up with a set of experiences and aptitudes different from their forebears. Shoring up the breach demands the presumption of further equivalences, such as that learning to write on a typewriter is more or less the same as learning to write on a computer or that learning to use a rotary phone is more or less the same as learning to use a mobile phone. But that "more or less" opens up a margin for error that must be wished away with the help of that first equation, itself imprecise: one generation's youth is more or less the same as another. The result is a loop bound to introduce distortion with each repetition. The concept of "youth culture," in other words, is motivated by the desire to stop the very process of development it supposedly seeks to trace.