It's a familiar phrase. While driving to the grocery store, Peter will ask,

'"How much further do we have to go?'"

Now if Quinn knows her usage rules she ought to reply,

'"Exsqueeze me?'"

Meaning:

'"What are you talking about? Further denotes degree, farther denotes distance.'"

Farther is a word that has long been synonymous with further. Most people use further for both meanings. But in recent times, the definition of the two has been rightfully split (completely synonymous words would be redundant), and so there are misapplications of the words everywhere including movies and television shows. Even some dictionaries continue to blur the distinction as some will indicate little to no difference between the two (dictionary.com plays down the difference but merriam-webster.com articulates it well). However, since writing is about communicating, if we can make our meanings more clear to the reader, we will. So why all the confusion?

1) Sometimes we mistake degree for distance:

a) Ex:

Wrong:
'"I'm training for a marathon, and I haven't much farther to go.'"

At first, we may be tempted to think it is indeed distance that we're talking about. After all, the subject of the sentence is training to run a great distance. But notice that the sentence does not specify what sort of training the subject is doing. That means that the sentence is instead suggesting how far along the subject is in his or her training, which put another way, is the degree to which the subject is fully trained, thus requiring further.

2) More often we mistake distance for degree.

Most of the confusion between farther and further seems to stem from the fact that it can be fiendishly difficult to determine whether a given idea denotes actual distance. Many people are therefore propelled to use further much more often than farther.

a) Ex:

Wrong:
The video game store is further away from the mall.

At first glance, the meaning doesn't seem entirely clear. We may be led to think that the writer is making a comparison, suggesting the degree to which the video game store is far away from the mall, thus making further the correct choice. The writer could also be referring to the time it takes to get to the mall (temporal matters have no clear winner in the further vs. farther fight). Context may help us decide the answer in many cases, but in the example above, we should assume that distance is the intended connotation, hence further is the incorrect choice. A true comparison should take the form in the Clearer statement.

Clearer:
The video game store is further than the mall.

or

Clearer:
The video game store is further away from the mall than the ice cream parlor.

or the sentence should be written as

Right:
The video game store is farther away from the mall.

b) Ex:

Wrong:
He is much further from an answer.

Right:
He is much farther from an answer.

Example b) confuses many people. Because the distance between the subject and the answer is not physical, people are tempted to choose further. But what we are discussing is not a degree. There is distance between the subject and the answer, just not tangible distance. To help illustrate the point, we can reword the sentence to say,

He is far from an answer.

And in general, when we can use far, we can use farther.

3) The usage is further complicated by the fact that further is also used in a number of situations where neither distance nor degree are the intended meaning.

a) Ex:

I don't want broccoli for dinner, further, I don't want any green vegetables whatsoever.

b) Ex:

We should discuss the topic no further.

In Example a), we use further as a synonym for moreover, and in Example b), we use further as a synonym for more. Many such examples exist, helping to create an atmosphere in which people assume that further is always the correct choice. But we know better, with the help of our new incredibly appearing word.

Do not despair! Correct word usage can be challenging, but the thought process we use to determine our word choice also helps us to get a clearer picture of exactly what we mean to discuss. The more we think about what we write and what we write about, the more lucid and salient our writing will be.