Know that the main requirements are four: Is it a question about existence and what? It is a question about the truth expressed by quiddity and how. It is a question about the state and why. It is a question about cause and cause. People disagreed about which of them is correct to ask about the truth, and they agreed on the word “is,” for it is conceivable that He asked about the truth, and they disagreed about what remained. Some of them forbade it, and some of them allowed it. Those who forbade it were the philosophers and a group of the sect who forbade it rationally, and some of them forbade it legally.