If Beethoven indeed wrote dynamics last, that is where as performers we must start thinking : for these are the basic building blocks of listening, of the experience of music (before harmony and melody), that is truly where the shape takes form in the mind’s eye : dynamics are the key to understanding the formal and therefore expressive innovations that Beethoven pushes around within the very distinct parameters of the material of his works. The dilemmas in Beethoven’s works all lie in the relationship from form to dynamics, from motivic transformation to dynamics, from tempo to dynamics (and in that sense only, for sound production is at the heart of all stages of the experience of music). And that remains true, even if he didn’t write them last.
As an answer to the research question (how can we, as performers, perceive new spectrum of dynamics and writing implied in those works, whether that is on a formal, instrumental, emotional level?), the way a performer may perceive the new spectrum of musical meaning in Beethoven's work is through a clear examination of the place and shape of a written sign on the score (if it goes over a note, beyond, etc) and link this to the form and shape of the work - and all the signs on a score, as for example, the first movement of the Kreutzer Sonata, combine and oppose each other in such a way as to generate motion and reflection in the hierarchy of parameters in a work: the written dynamics, as we've seen, could almost seen as a secondary ingredient in the preparation for the performance of a work, for the internal (harmonic, textural, cuntrapuntic) elements of the music are the more elusive and prone to change parts of the score. Dynamics operate on a higher level than the grammatical qualities of the former categories, for they are what provides and induces drama in a work: it is in this way (dynamics) that Beethoven is able to change the coordinates of his own aesthetic from work to work. We, as performers, must realize what these dynamics signs mean, especially with the new theory of 'special' dynamics, which bring a new level of 'pure music', a pure relationship between form and contents, shading the vocal and instrumental qualities of each performer according to the music's own will, qualities sometimes required to be present, sometimes absent, leaving music by itself and its own emotional power.
There is an inherent antagonism in the concerto, because the difference between the two parties of soloist and orchestra existed even before the material was chosen, and therefore a strange phenomenon happens, a sort of symbological representation of the musical world of the work through the hierarchy of subjects/themes, of that out of which form exists, and the case of musical form is all the more pregnant in this impossibility : musical form cannot be expressed through sound, but its form can take the shape and content of its own coming to being.
Some composers are obsessed with sound itself, but must yet retain a logic so as to be able to write down a score. Other composers are taken away by the abstract form, the ideal abstract work that is universal, unbeatable, inalterable (a good example might be Bach’s cuntrapunctal summits). Beethoven realized quickly, and with a fair share of luck and deception, that indeed, as a composer, matter – sound as "photons of pitch" – is both an illusion, and the very ‘thing’ we desire as creators. Its existence as a poetic object threatens form as a constructive being-in-time. Through this poetics of creation, we may be drawn into the inertia of sculpting sound and entering its seemingly infinite sphere, or be drawn into the fury of a dense form ; or on the contrary, the inertia of a previsible form or the unbelieved black butterfly of fantasy.
After these examples, we can understand that the complex set of parameters to be taken into account in a musical work does not allow us to have a classical approach to classical form, especially in this kind of musical ethos, given the complex relationship between the soloist writing and the instrument’s possibilities, whether they be reduced compared to the orchestra or idiosyncratic to itself.
Beethoven’s unending quest for formal innovations pushed outward and inward the need for exploration and decisiveness/direction in his works. That is why I think he devised this new tool for writing down dynamics : so as to ensure and give confidence to the performer’s own understanding of the music.