When bad weather prevented navigators from seeing the sun,moon or stars, they had to use a method called "dead reckoning" to find the ship's position.

VOA: special.2009.12.23

For reason, he writes in a famous passage, "for reason is nothing but reckoning, that is adding and subtracting the consequences of general names agreed upon."

对理性而言，他在一个著名的段落中写到，“推理就是一种计算，也就是将公认为标示或表明思想的,普通名词所构成的序列相加减“

耶鲁公开课 - 政治哲学导论课程节选

If a ship was sailing in the middle of the ocean, a navigator could make mistakes using dead reckoning and no harm would be done.

VOA: special.2011.07.06