Conceptual Sequences

It is impossible to read a summary like the one in the previous post without getting the impression that several works by different sf writers form a single, continuous series. In fact they are not a linear series but they are a conceptual sequence:

The Time Machine implied but did not address temporal paradoxes;

Lest Darkness Fall and Bring The Jubilee implicitly raised the question - if time travelers can change the past, then might some organize to preserve it?;

Poul Anderson did write a series in which he developed this idea and later refined it further.

Similarly with future histories: Anderson modeled his Psychotechnic History on Heinlein's Future History, then joined two originally unconnected futuristic series into the unplanned Technic History, which follows a pattern similar to that of the Future History but on a vaster scale. Thus, these three future histories are not one series but are a conceptual sequence.

James Blish observed that sf writers borrow and copy each others' ideas to an extent that would be called plagiarism in any other genre. If one writer asks and answers a question, this challenges others to answer the same question differently. Blish described the exploration of Jupiter but was unable to imagine anyone becoming comfortable there...