Theater of Machines, Part 1

An ornamental initial letter H.Because the principia first principles or initial foundations in every art have no small dignity and advantage, for through them all other matters in such an art may be proven and demonstrated, but they themselves cannot receive any demonstration, therefore they are called by some who are practiced in the mathematical art suppositiones suppositions, that is, certain propositions or conditions. For such are set down as certain and true, and allow for no doubt. Although such principia are also called by others petitiones postulates or conditions, for if we wish to engage with someone who wants to oppose us in the art we have in hand, we must, before we begin the disputation formal debate, learn from him whether he confesses and wishes to allow them, so that we may prove and demonstrate our arguments and intended opinion from them. For where one will not confess or allow such propositions, to which we must agree and unite before such a disputation, we cannot dispute with him, according to the