"A good historian will use the fact that he can't divorce himself from his own viewpoint as a reminder to be extremely cautious. A bad one will use it as an excuse to indulge his particular biases."

I'd say this is also true in the broader sense of how a person chooses to live in an inherently muddled world. You can take obstacles and confusion as a call to action and vigilant reflection, or you can use them as an excuse for giving up and accepting mediocrity.