Beethoven's fortepiano sonata is for me the most radical, imaginative and inventive music of this gnarled, idiosyncratic genius. The cosmos of a universal free spirit who was overwhelmed by the antimatter of his spiritual brooding is basically written for no instrument at all.
Even the immense first movement, which unabashedly pushes the piano's possibilities to their limits like the sketch of a great symphony, stands there like a classical temple already overlooking the achievements of Romanticism.
And the diabolically scampering Scherzo, which seems to have overtaken Schumann and Mendelssohn, feels like a little witches' sabbath before Beethoven makes us lose all norm, indeed the world, in one of the most poignant, profound and intimate Adagio movements. But the incomprehensible happens in the fourth movement, a maddeningly disturbing, highly virtuosic fugue that throws all the rules of even the most accomplished contrapuntist out of the water, which I consider to be the ultimate in composition and which is a century-old monument of philosophical profundity both in its disregard for the usual contrapuntal rules of the time and in its overwhelming mastery of them. This music is the quintessence of Beethoven's spirit and thus the big bang of musical thought, not because of but despite its proximity to pianistic unplayability.