Accordingly while the study of metaphysics and the explanation of the allegories of Scripture are thus shown to be a necessity of intelligent belief, it is not proper to begin with these difficult subjects. One must first be mature intellectually and possessed of the preliminary sciences. Otherwise the study of metaphysics is likely not merely to confuse the mind in its belief, but to destroy belief entirely. It is like feeding an infant on wheat bread and meat and wine. These are not bad in themselves, but the infant is not prepared to digest them. That is why these matters are given in the Bible in the form of allegories, because the Bible is intended for all--men, women and children--not because metaphysical ideas are injurious in themselves, as some fools imagine, who believe they are wise men. For beginners it is sufficient that they have the right view by tradition and know the existence of certain beings, without being able to prove the opinions they hold, or to understand the essence of the being in the existence of which they believe. This they will acquire gradually if they are capable.[258] There are five causes preventing the study of metaphysics on the part of the general masses. First, the difficulty of the subject itself. Second, the limitations of all people's minds at the beginning. Third, the great amount of preparatory training that is necessary, and which everybody is not ready to undertake, however eager he may be to know the results. And to study metaphysics without preliminary training is worse than not to study it at all. For there is nothing in existence except God and his creation. To know God's existence and what is and is not proper to ascribe to him we must examine his creation; and thus arithmetic, the nature of number, and the properties of geometrical figures help us a great deal in determining what attributes are inapplicable to God. Even much more important for metaphysics is the study of spherical astronomy and physics, which throw light on the relation of God to the world. Then there are some theoretical topics which, while not directly of help in metaphysics, are useful in training the mind and enabling it to know what is true demonstration. One who wishes therefore to undertake the study of metaphysics, must first study logic, then the mathematical sciences in order, then physics, and not until he has mastered all these introductory branches should he take up metaphysics. This is too much for most people, who would die in the midst of their preparatory studies, and if not for tradition would never know whether there is a God or not, not to speak of knowing what attributes are applicable to him and what are not.