"How do you do?"
The comedian replied, "How do I do what?"
Which came first? Historically the violin came first. But the piano changed everything about the acoustical world in which string intonation ruled supreme.
With the piano came a previously-unimagined fog. It might be compared to the difference in sound between a solo violin and a violin section. Notice the difference next time you have occasion to hear what I am talking about. It is not unlike the difference between a single bass note and one doubled at the octave on the piano.
Except that every pitch on the piano resembles the string section sound, for the simple reason that every pitch is made by three vibrating strings inevitably vibrating slightly out of sync with one another, therefore with fuzz around the edges of their frequency.
Can a violin make peace with such an arrangement or does it always have to project like the concerto soloist? That depends on the ear of each player, and that depends on the desire of each player to produce a new sound. It involves a sort of acoustical magic that fuses the two players in one element that neither one can produce alone.
The current Tonal Refraction work is a return to Beethoven's Op. 24 Sonata in F for Piano and Violin, the "Spring." It is very much concerned with frequent intersections of the two sounds, made more evident by their wide separation. What a splendid demonstration of what happens when this magic is allowed to happen.
Have you ever heard it performed in such a way that you feel that you are beholding that level of meeting?