Further or farther? Which one do you use in which situation? As a general rule… they’re pretty interchangeable, but many people use the following rule: Further refers to metaphorical distance, whereas farther refers to physical distance.
Over at The New Yorker, they have a theory about further versus farther, and it’s a nice quick read. They talk about the etymologies of the words, how it’s been used, and they provide several examples of how to use the words… and how it doesn’t particularly matter which one you use. Onwards!