These two words recognize different senses of distance: the far in farther can help remember that this is actual physical distance, while further is metaphorical; for instance, I can say that with this post I am furthering grammatical awareness. “Farthering,” on the other hand, ought to sound wrong to any English speaker.
- “My house is the farther of the two.” vs “She needs no further introduction.” (DailyWritingTips, below)
Do you have further favorite examples of farther vs further? Feel free to share them in the comments!