Because the true perfection of a practical occupation consists not only in knowing the actual performance of the occupation but also in its explanation, why the work is done a in a particular way, and because the art of calculating is a practical occupation, it is clear that it is pertinent to concern oneself with the theory.

A peace that comes from fear and not from the heart is the opposite of peace.

Because the true perfection of a practical occupation consists not only in knowing the actual performance of the occupation but also in its explanation, why the work is done a in a particular way, and because the art of calculating is a practical occupation, it is clear that it is pertinent to concern oneself with the theory.