What genre best defines John Progress based on this excerpt from the story Now as Christian was walking solitary by himself he espied one afar off come crossing over field to?

Based on the excerpt you provided, it's highly likely that the genre is allegory.

Here's why:

* "Christian": This name immediately suggests a religious or spiritual context, a common element in allegories.

* "walking solitary": This phrase hints at a journey of self-discovery or spiritual growth, another characteristic of allegory.

* "espied one afar off": This phrase suggests a meeting with a significant character, often symbolic, a staple of allegorical narratives.

* "crossing over field": This imagery likely represents a metaphorical passage or transition, a common theme in allegories.

Without further context, it's impossible to be certain. However, the excerpt strongly suggests an allegorical setting, likely exploring themes of faith, morality, or the human condition.