How far into the future can we reasonably plan?

"Language, actually, was developed in response to these tools--writing, too. My point is that the key technology that runs through all of this is communications. Humans, in essence, are a communicating organism. We started as a very dispersed species, became more organized in cities, and then came mass communications. The invention of the printing press brought books to large populations. Then, in this century, radio and television completely changed the psychology and social setting of most of the world's people."