The central place of beauty in Plato's thought is witnessed in the Dialogues Phaedrus and Symposium. The perception of beauty induces anamnesis, a recollection of previous acquaintance with the universal, the real, or, in a word, the forms. Beauty is capable of higher and higher manifestations, and once apprehended it induces eros, or the passion that drives the soul towards a spiritual ascent, a journey of knowledge combined with love (Symposium, 210A) culminating eventually in a purely intellectual apprehension of beauty, goodness, justice, and wisdom. The connection between physical and intellectual beauty is mediated through the notion of light: there is an intrinsic analogy between the light of reason (or the Good) and the light of the sun, and between physical and intellectual vision. The divinization of light is as old as Zoroastrianism, reappears in Heraclitus' conception of the first principle as fire, and is developed in Neoplatonism, from whence it passes to the medievals. For Plotinus beauty is not confined to the good or the perfect. The entire sensory world is beautiful, because it is via the embodiment of spiritual forms that light infuses the world of matter. In Augustine beauty has the function of manifesting the divine: the non-human part of creation wants to make known (innotescere) the nature of the divine. In beauty fullness of form radiates from an object; a thing is as it should be in the highest degree (Augustine here connects the Latin for form, forma, with beautiful, formosa). All creation radiates in this way, and is a reflection or speculum of the Divine beauty. The medieval celebration of light and colour, culminating in the poetry of Dante, marks the continued power of this idea. In the modern era, beauty has become a contested concept in aesthetics, in the sense that some theorists have seen it as dispensable, and an obstacle to the perception of more detailed aesthetic values such as being sublime, harmonious, graceful, dainty, winsome, elegant. For others it remains the central, unifying concept appropriate to pleasure derived from the senses or from intellectual contemplation. Things of almost any category (persons, elements of nature, and also geometrical figures and mathematical proofs) may be beautiful, and experiencing them as such retains the Platonic associations with value and goodness, and with the ‘revelation’ of something deep, just as much as with the pleasure that is felt. Discovering how there can be a concept subject to these constraints is the topic of Kant's Critique of Judgement.