 Every theoretical science is composed of principles and problems. The results may be called problems (masa’il). The principles can be concepts (tasawwur) and they are uttered by spoken sounds that are individual in potency or in actions. The principles can be given assent to (tasdiq) and they are uttered by sentences that are statement-making and necessary. There are sciences like geometry where the principles are more general and anterior. By “principles”, I mean these concepts (tasawwurat): the triangle is anterior to the equilateral triangle and to other kinds of triangles. (IB-BA: 65.5–11)