 The first law, the lex veritatis, or law of truth, stated that every theorem in an art must be general and indispensable. For example, a theorem stating that the angle of a triangle is a right angle would not be a false statement since there are indeed triangles with right angles. But since it is not true in relation to all triangles, such a theorem would violate the law of truth. A theorem which states that the sum of the degrees of the three angles of a triangle is 180 would, however, be totally correct and generally true.