In 1806 Pfuel had been one of those responsible, for the plan of campaign that ended in Jena and Auerstädt, but he did not see the least proof of the fallibility of his theory in the disasters of that war. On the contrary, the deviations made from his theory were, in his opinion, the sole cause of the whole disaster, and with characteristically gleeful sarcasm he would remark, “There, I said the whole affair would go to the devil!” Pfuel was one of those theoreticians who so love their theory that they lose sight of the theory’s object⁠—its practical application. His love of theory made him hate everything practical, and he would not listen to it. He was even pleased by failures, for failures resulting from deviations in practice from the theory only proved to him the accuracy of his theory.

He said a few words to Prince Andréy and Chernýshev about the present war, with the air of a man who knows beforehand that all will go wrong, and who is not displeased that it should be so. The unbrushed tufts of hair sticking up behind and the hastily brushed hair on his temples expressed this most eloquently.