 The second law was called the lex justitiae, or law of justice. Ramus regarded this as the most important of the three laws. It ensured that justice was done to all the arts. No theorem belonging to one art should be allowed to trespass into the subject matter of another, since that would be unjust. This law also demanded that all parts of an art should be homogeneous. It was on the basis of this law that Ramus objected to Copernicus’ planetary hypothesis (see  §1.4  above). He held that Copernicus was not allowed to put forward theories as to how the planets really moved in the heavens, which belonged to the art astrophysics, while at the same time using mathematical hypotheses, which belonged to the art of mathematics. To Ramus, this law was fundamental for the purpose of organizing a new curriculum and was also, as we shall see, an important aspect of his method (Hooykaas 1958: 65).