Originally Posted by
mikeh375
It's much more nuanced than that. It's fair to say that Bach did frequently let the line override the vertical, resulting in a particular harmonic spice that gives his work immense emotional power, but one can't write counterpoint in his style without harmonic thought and consideration - it's just not possible, the two trains of thought are the two sides of a single coin.
Part of Bach's genius was to expand the reach of the emotional potential in momentary dissonance imv. He did this by allowing the linear to follow it's own logic seemingly unimpeded at times, giving rise to clashes that as a result, seem inevitable but also calculated. However, the individual lines are also cogniscent of their vertical obligations and as such are also determined by the vertical.
Bach, as well as thinking contrapuntally, also had to think harmonically and not just in a "very general sense", but rather from beat to beat, phrase to phrase, cadence to cadence and as a consideration for defining form.
The best way to gain a deep understanding of the synergy between harmonic and contrapuntal thought is to learn to write counterpoint in Bach's style, it then becomes clear that one needs the other in more than a superficial or general way.