"In the treatise, De quantitative animae, St. Augustine lists seven stages through which the soul normally passes as it advances to contemplation. The first three stages refer to the vegetative, sensitive and rational levels of human life. But the Christian does not begin to make true progress toward perfection until the fourth stage, which is that of virtue, accompanied by purification. The fifth stage is called tranquility, to denote the peace that follows from control of passions. The sixth stage is called the entrance into the divine light (ingressio in lucem), in which the soul seeks to penetrate the divinity; there, if it succeeds, it passes on to the seventh and final stage which is that of habitual union and indwelling (mansio). That this last stage is truly mystical contemplation and not the philosophical contemplation of a neo-Platonist is evident..."