What are the differences between until now and so far? [closed]

What is the difference between Until now and So far?

Please explain to me what the difference is between them.

Solution 1:

The difference, as usual, is between the metaphor involved, if there is one.

Until is one of the very few words in English that actually refers to time duration
(others include when, while, now, then, during, duration, and endure). All the other ways we refer to time, like spend time, are metaphorical.

The metaphor involved in so far (as in up to now and up to the present moment)
is the Time Passing Is Motion metaphor theme.

There are two versions of this, depending on viewpoint. As Kövecses labels them,

1. TIME PASSING IS AN OBSERVER'S MOTION OVER A LANDSCAPE:
   i.e, the observer is in motion along a path while passing stationary temporal events
   (Up to now is licensed by this version)
2. TIME PASSING IS MOTION OF AN OBJECT
   i.e, the observer is stationary while moving temporal events pass by

Both are cognitive nonsense, of course, and they're even contradictory,
but that's normal for metaphors, which are theories invented by four-year-olds;
they all start out as nonsense in the first place, and continue by violating
the first premise of logic:

A proposition cannot be both true and false.

In using up to now, the speaker is conjuring up the image of observing temporal events while moving up (i.e, along) a path in a landscape, and is positing some proposition of all the events that have been observed along the path (from some indefinite starting point). Time is strictly metaphoric here.

With until now, however, no metaphor is used; this is a direct reference to perceived duration.

Solution 2:

I would say that "until now" suggests that the condition you are about to describe is at an end, "So far" suggests that the condition is still ongoing.

"Until now, no all-woman team has won the tournament", means that an all-woman tournament just won for the first time ever.

"So far, no all-woman team has won the tournament" suggests that that event (the all-woman team winning) has not happened.