He believed that air was the substance of all things. For example, when air is thinned out, he thought, it turns heated and becomes fire. When air is thickened, it condenses and becomes water and solid matter. | He believed that air was the substance of all things. For example, when air is thinned out, he thought, it turns heated and becomes fire. When air is thickened, it condenses and becomes water and solid matter. |