Part of practicing Beethoven's music involves being deeply curious about the meaning and nature of his dynamic indications. A professor at Western (THE Brett Kingsbury) recently made the comment that in Mozart, if there is no dynamic indicated, one can safely assume that the dynamic is forte. But in Beethoven, if the dynamic is not indicated, one should consider it to be piano. I found this statement to be incredibly interesting. For one, it brings home the point that from composer to composer, you cannot necessarily induce that all markings indicate the same phenomena or even necessarily inform each other, although they may. What an exciting thing to know that each composer is a world unto itself. For two, it tells you something about the ethos of the dynamic worlds.
Beethoven writes "p dolce" at the beginning of the fourth piano concerto. The opening entrance, given to the piano, expresses that "in this place, thing are right and true - they are as they should be". The magic that follows the piano's opening invitation is thrice compounded by the harmonic surprise, the instrumentation, and the dynamic indication. First, Beethoven does that Beethovenian thing where he uses chord III where I should be used - shocking and other-worldly sounding. The sharing of melodic content but shfit in instrumentation from piano to strings indicates the beginning of a dialogue between soloist and orchestra. Both shift to chord III and shift to orchestra would perhaps suggest an increase in dynamic level.
The fact that Beethoven instead writes pp for the orchestra's response tells us something about the nature of this concerto.
This concerto is not the 3rd Concerto. It is not the Emperor. It is not the Waldstein or the Hammerclavier. It is something else.