I've just had another conversation with my friend, Zoe, who has solved the riddle of travelling backwards through time. She's just returned from the year 2050: her memories of the future are hazy but fascinating.
In fact she's been to not one future but two - it turns out that all the speculation among physicists about multi-verses is spot on - there are billions of universes, each representing a possible future for us, and she's been to two of them. The rules of travel through time, and between universes, mean that she is unable to remember much detail, but one fascinating point from first of the two universes she went to is that the accepted paradigm in fundamental physics is the "God with a sense of humour hypothesis." Apparently this is the only hypothesis which fits all the known facts, in particular the apparent arbitrary oddness of the laws of nature.
About 20 years ago - talking now from the first 2050 future - two principles from physics migrated to mainstream culture with far-reaching effects. The first was the idea of an absolute limit to the complexity of ideas that the human brain could deal with. The second was the principle that exact laws of nature were unobtainable in the sense that they necessarily needed ideas more complex than this limit. Together these yielded a third principle that knowledge should be designed so as to reduce "cognitive strain" as much as possible. This last principle then led to dramatic changes in the framework of human knowledge. Instead blaming children who found their school work too difficult, extensive research was undertaken to reduce the cognitive strain (or to make it easier). Similar efforts were made with more advanced ideas: for example, Schroedinger's equation - the basic equation of quantum physics that describes how things change through time - was transformed to a user-friendly bit of software with a sensible name that even young children could use and understand. The new version was formally equivalent to the original equation, but far more accessible
This change had a number of far reaching effects. Universities stopped providing degree courses for the masses because the content of old-style degree courses was just too easy and commonplace. A lot of it, like Schroedinger's equation, had entered mainstream culture, and some of it was accessed on a just-in-time basis when needed.
Progress at the frontier of most disciplines had accelerated sharply when these changes came through. The fact that the basics were so much easier meant that there were many more people working at the cutting edge, and the fact that they got there quicker meant that there was more time to work on problems. The old idea that experts spend ten years acquiring their expertise was still true, but the amount of useful expertise you could acquire in your ten years was much, much more.
Cancers, heart disease, and unplanned death in general, were largely conquered, and Zoe was impressed with the solution to the problem of over-population that this would cause, but unfortunately she couldn't remember what this solution was. (Infuriatingly, the rules of time travel and universe hopping set by the God with a sense of humour means that Zoe could only remember a few details of this future.)
The second future had much more in common with the present. The school curriculum was virtually unchanged, university degrees now lasted for ten years, cutting edge research was even more dominated than it is now by professional researchers using language and concepts almost completely inaccessible to laypeople. Cancer and heart disease rates had improved but only marginally.
Zoe much preferred the first future. Unfortunately the God with a sense of humour, while allowing her to go and have a look, and absorb some of the atmosphere, blocked details like how the user-friendly version of Schroedinger's question worked, and the nature of the advances that had largely eliminated common diseases.