{I}t was really only in the generation or two before hers that the idea had started to traverse the spectrum of likelihood in the popular imagination, beginning at unthinkable, progressing to absurd, then going from possible but unlikely to probable and likely, before eventually arriving – round about the time of her birth – at seemingly inevitable.
The quote describes the evolution of a concept within society's mindset over time. Initially deemed unimaginable, it transitions through various stages of acceptance, from absurdity to the recognition of its possibility and likelihood. This shift reflects a significant change in cultural perception and imagination regarding the idea.
By the time of the protagonist's birth, what once seemed impossible has become almost an unavoidable reality. This progression illustrates how societal beliefs can evolve, showcasing a shift from skepticism to an expectation of acceptance. It highlights the dynamic nature of ideas and the impact of generational change on perceptions of potential outcomes.