And here I must needs observe, that as reason is the substance and origin of the mathematics, so by stating and squaring everything by reason, and by making the most rational judgment of things, every man may be, in time, master of every mechanic art.

这里我必须说明：正如理性是数学的本质与源头，只要依理性来分析、衡量一切，并对事物作出尽可能合理的判断，任何人经过时间的磨炼，都可以掌握各种实用技艺。