Furhter or Farther up the road to understanding
Farther or Further?
In reality, based on actual usage in normal speech, there is no real difference between further and farther for most Americans. Traditionally, however, farther is considered to apply to physical distances while further applies to metaphorical and figurative distances.
Farther refers to length or distance. It is the comparative form of the word far when referring to distance.
Further means "to a greater degree," "additional," or "additionally." It refers to time or amount. It is the comparative form of the word far when meaning "much."
Correct:
(Refers to distance)
Correct: This plan requires further study.
(Meaning "additional study," refers to amount)
Correct: According to my timetable, we should be further along.
(Refers to time)