Bach, a born fighter who exulted in overcoming apparently unsurmountable difficulties, succeeded in doing the nearly impossible: to write four-part fugues and polyphonic variations for an instrument whose very nature seems to exclude such devices. … The sonatas and partitas are … typical not only of Bach’s personality but of the artistic conceptions of the Baroque era. At that time the walls of houses were occasionally decorated with paintings simulating vistas of wide colonnades and formal gardens. Such embellishments require the working of the inner eye, just as the implied polyphony and rich harmonic texture in Bach’s compositions require the co-operations of the inner ear.

Karl Geiringer