The Ultimate Defeat Of Enemies Both Within And Without?

I wrote here that psychological conflicts destroyed the Solar Union and that cosmic complexity destroyed the Stellar Union. However, Poul Anderson's "The Chapter Ends" describes a later era when both of these problems have been solved.

A man can:

will negative feelings out of his trained nervous system;

mentally control the most basic cosmic forces with only a small expenditure of energy by using an artificially mutated section of his brain.

Thus, he can fly not only through the air (see image) but also through interstellar space at trans-light speeds.

Superheroes are a distinct genre, incorporating elements of fantasy, sf and action-adventure. However, they originated as sf: Superman's powers are extraterrestrial, not magical or supernatural, in origin. Over the decades, his powers went up and down the scale:

able to leap tall buildings at a single bound;
able to fly;
able to survive in vacuum and to fly across interstellar distances in seconds.

Script writers sensibly scaled his powers back down again. Thus, John Byrne's Superman could fly to the Moon and back but was not able to remain conscious indefinitely in vacuum. However, Poul Anderson presents future human beings with the power of interstellar flight.

Although "The Chapter Ends" does not seem to fit with the Psychotechnic History in terms of historical details, it nevertheless presents an interesting scenario where the apparently insuperable problems of this future history have eventually been solved.