I have now read the second De Quincey essay in my collection; it’s called “On the Knocking At the Gate in Macbeth,” and it tries to explain why De Quincey finds the knocking that takes place after Duncan’s murder so eerie. The essay is about five pages long, and it makes a fairly simple point about Macbeth (the knocking brings us back from the horror of murder to the everyday world — and returning to the everyday world deepens the horror of murder), but along the way it is full of digressions, taking in a philosophical point about the mind, the story of a real-life murder, what it’s like to witness someone fainting, and what it’s like to watch a state funeral procession.
Here is part of the philosophical digression:
Here I pause for one moment to exhort the reader never to pay any attention to his understanding when it stands in opposition to any other faculty of his mind. The mere understanding, however useful and indispensable, is the meanest faculty in the human mind and the most to be distrusted: and yet the great majority of people trust to nothing else; which may do for ordinary life, but not for philosophical purposes.
I love this philosophical digression that warns us against paying too much attention to our understanding! He goes on to illustrate this point with an example: if you were to ask someone to draw a picture of a street, they probably wouldn’t do a very good job, unless they happened to know the rules of perspective. Here is why:
The reason is — that he allows his understanding to overrule his eyes. His understanding, which includes no intuitive knowledge of the laws of vision, can furnish him with no reason why a line which is known and can be proved to be a horizontal line, should not appear a horizontal line …
Even though we can see with our eyes the way a street actually looks, our understanding takes over when we try to draw it and it messes us up. We’d be better off trusting our eyes and getting our mind out of the way.
The purpose of this digression?
But, to return from this digression, — my understanding could furnish no reason why the knocking at the gate in Macbeth should produce any effect direct or reflected: in fact, my understanding said positively that it could not produce any effect. But I knew better: I felt that it did: and I waited and clung to the problem until further knowledge should enable me to solve it.
That’s a long way around to make the point that reason only gets us so far and that the senses, emotion, and intuition can carry us farther, but I do like taking the long way around to get to one’s point, at least when it’s done as De Quincey does it, with something interesting along the way.