Even though farther and further seem interchangeable, there’s actually a subtle difference.
The Short Story
If you can measure the distance, use “farther.”
You just need to walk a little farther.
How much farther until we get to Piama’s house?
If you can’t measure the distance, use “further.”
If I stretch myself a little further, I can master this technique.
She furthered their relationship by talking about her past.
The Novel
Both “farther” and “further” refer to distances. The subtle distinction here is that we use “farther” for physical distances and “further” for figurative distances.
If we can take a measuring tape and measure between two physical points, use “farther.” Now, don’t take that too literally. Of course, we don’t have a measuring tape that’s long enough to measure the distance between the earth and the moon, but it physically can be measured. If it can be measured in inches or miles or kilometers, use “farther.”
So what is a figurative distance? When would we use “further?” A figurative distance is something that we can’t measure with a measuring tape. Think of how far you have come in a relationship or how much you have left to complete a goal. We can’t use a measuring tape to determine how much your relationship with a new friend has grown. And we can’t quantify how many inches you have left to complete a goal. These are figurative distances. We can also use “further” to talk about nonphysical entities, like emotions. “I was further enlightened after listening to the discourse on nuclear physics.” Some other common sayings are “without further ado” or “look no further.”
Although both words are used interchangeably in speech, there is an actual difference between “farther” and further.” And now you know when to use each one!
The Examples
“The shy, sickly boy Yoseb had left eleven years ago had grown into a tall gentleman, his gaunt body depleted further by his recent illness.”
(Lee, Min Jin. Pachinko. United States: Grand Central Publishing, 2017.)
The state of the sickly boy’s body can’t be measured with a measuring tape. It is a figurative measurement, so we use “further.”
“But sometimes the fifolet play tricks, leading people farther and farther from safety until they’re lost forever deep in the swamp.”
(Sain, Ginny Myers. Dark and Shallow Lies. United States: Penguin Young Readers Group, 2021.)
This one is a little tricky because “safety” isn’t a physical object. But in this case, there is a physical place where people are considered to be safe compared to a physical place where they are in danger. We could use a measuring tape to measure the point from where the people were safe to where the fifolet (swamp spirits) are leading them.
“But now, they were wearing full—on floor—length black robes made of velvet, taking it way further than those other women had.”
(Hankin, Laura. A Special Place for Women. United States: Penguin Publishing Group, 2021.)
In this sentence, Jillian, the main character, has just found women dressed like witches. Before, she had just heard women referring to themselves as witches. Dressing up as a witch has taken this reference further than just talking about it. Because we can’t literally measure the phases between referring to one’s self as a witch and dressing up as one, we know this is a figurative distance. That means we should use “further.”