Lesson #1:
Further vs Farther: Which do I use?
You might have seen the common answer of "farther is for physical distance and further is for metaphorical distance" but it is not as simple as that as any writer finds when putting the words into practice. To understand each one, we have to break them down.
The issue with these two words that many writers come across is that both words can be adverbs, adjectives, or verbs, and can even have multiple meanings depending on the context. Due to to the English language being the way it is, sometimes it is clear which word you should use, and other times it doesn't really matter. They are usually interchangeable as adverbs, with some usage guides keeping the rule of physical vs metaphorical distance, but it isn't a strict rule and you can use farther in a metaphorical sense as seen in many published papers and studies.
ADVERBS
In this context, further is usually used to mean "moreover" or "additionally" which farther cannot be used for. You don't typically see farther used in this context as it would be awkward to start a sentence with it, but the important thing is that in this context the two words are not only defined in terms of distance. For example, you wouldn't usually say "Farther I'd like to discuss the difference between further and farther."
ADJECTIVES
When used as adjectives, they are still defined as meaning "additionally", but further is almost always used. Some writers have used farther as an adjective, but it is rare and not widely used and accepted. For example, you would say "He began without any further greeting."
VERBS
As a verb, you would use further. For example, you further your career, you don't farther it. You can technically use farther as a verb but it is so rarely used and accepted that most professors and professionals would say you are incorrect for using it.
The takeaway from this lesson is that when deciding between further and farther, you will almost always use further, unless you are talking about a physical distance, in which case you would use farther.
