Augustine also expanded the Roman notion of number in rhythm to beauty more generally by regarding rhythm as the sole source of beauty. According to Augustine, every experience of beauty originates in and is determined by rhythm. Even though he placed heavy emphasis on the beauty of number and therefore equality or balance, he also realised the purpose of contrast or the inequality of parts. For example, he attributed the beauty of the world to the contrast between things and therefore he believed the correct and natural placement of things results in beauty. Pseudo-Dionysius developed the Classical notion that the beautiful is aligned with the good by writing that beauty is the manifestation of goodness. He justified this assumption through his idea that God is the Cause of everything, meaning that beauty and the beautiful are the same because they have the same cause. He asserted that all things have beauty because everything originates in the Cause and that this means nothing can lose its beauty. For Pseudo-Dionysius there exists an Absolute Beauty from which all material beauty is derived through 'emanation'. This results in the earthly encounter with beauty that is divine, even though it may appear imperfect. Such a conception, according to Ananda K. Coomaraswamy, is important because medieval aesthetics were thereafter 'fundamentally based on [his] brief treatment of the Beautiful' in "On the Divine Names". This treatment also involved the important step of using 'Beauty' as a divine name. According to Brendan Thomas Sammon, this approach influenced how St Thomas Aquinas came to treat beauty. St Thomas Aquinas gave two individualised definitions of beauty in the "Summa Theologica." The first asserts that the beautiful is experienced through visual pleasure, while the second states that the beautiful is a pleasurable perception. These amount to a single definition of beauty that accounts for both subjective and objective experiences of beauty where the emphasis on sight and perception creates a holistic groundwork for understanding beauty. His most historically important idea regarding aesthetics was that the beautiful is pleasurable, while not all pleasures are beautiful. Unlike his predecessor Pseudo-Dionysius, who started his aesthetics from the assumption of an absolute and divine beauty, Aquinas took material beauty subject to empiricism as his starting point. In departing from the Platonic transcendent, Aquinas moved towards Aristotelianism which enabled the exploration of the beautiful and the good as independent of each other. This move thus enabled Aquinas to develop an implicit criteria for beauty: actuality, proportion, radiance and wholeness.