“Nothing is so useless as a general maxim.”
“Nothing so comforts the military mind as the maxim of a great but dead general.”
“Nothing so precious as memory, nothing so useless.”
“act as if the maxim of your action were to become by your will a general law of nature.”
“Nothing made you feel so useless as another person's grief.”
“There is nothing so useless as doing efficiently that which should not be done at all.”