The disciples of Thales and Pythagoras, with the Stoics, are of opinion that matter is changeable, mutable, convertible, and sliding through all things. The followers of Democritus aver that the vacuum, the atom, and the incorporeal substance are the first beings, and not obnoxious to passions. Aristotle and Plato affirm that matter is of that species which is corporeal, void of any form, species, figure, and quality, but apt to receive all forms, that she may be the nurse, the mother, and origin of all other beings. But they that do say that water, earth, air, and fire are matter do likewise say that matter cannot be without form, but conclude it is a body; but they that say that individual particles and atoms are matter do say that matter is without form. CHAPTER X. OF IDEAS. An idea is a being incorporeal, not subsisting by itself, but gives figure unto shapeless matter, and becomes the cause of its phenomena. Socrates and Plato conjecture that these ideas are beings separate from matter, subsisting in the understanding and imagination of the deity, that is, of mind. Aristotle accepted forms and ideas; but he doth not believe them separated from matter, or patterns of the things God has made. Those Stoics, that are of the school of Zeno, profess that ideas are nothing else but the conceptions of our own mind. CHAPTER XI. OF CAUSES. A cause is that by which anything is produced, or by which anything is effected. Plato gives this triple division of causes,--the material, the efficient, and the final cause; the principal cause he judges to be the efficient, which is the mind and intellect. Pythagoras and Aristotle judge the first causes are incorporeal beings, but those that are causes by accident or participation become corporeal substances; by this means the world is corporeal. The Stoics grant that all causes are corporeal, inasmuch as they are physical. CHAPTER XII. OF BODIES. A body is that being which hath these three dimensions, breadth, depth, and length;--or a bulk which makes a sensible resistance;--or whatsoever of its own nature possesseth a place. Plato saith that it is neither heavy nor light in its own nature, when it exists in its own place; but being in the place where another should be, then it has an inclination by which it tends to gravity or levity. Aristotle saith that, if we simply consider things in their own nature, the earth only is to be judged heavy, and fire light; but air and water are on occasions heavy and at other times light. The Stoics think that of the four elements two are light, fire and air; two ponderous, earth and water; that which is naturally light doth by its own nature, not by any inclination, recede from its own centre; but that which is heavy doth by its own nature tend to its centre; for the centre is not a heavy thing in itself.