 Kant claimed that the main difference between the holistic unity of organisms and the holistic unities of artworks and natural beauties is the difference between a causal or existential unity and what he called a formal unity. In organic life, the reciprocal interdependence between parts and wholes is causal and existential in the sense that it is life-sustaining. Kant thought that in aesthetics, the reciprocal interdependence is formal, rather than causal or existential, in the sense that it does not explain the existence of the objects at stake, but their beauty. While, for example, a painting might continue to exist as a painting even if some of its parts changed (say, if its composition, shapes, or hues changed), the beauty of this painting is unlikely to survive such a change. In this case, it is the beauty of the whole painting that depends on its parts, and it is the beauty of the parts, rather than their existence, that depends on the beauty of the whole: for were the painting as a whole not beautiful, its parts would not be recognized as what they are, namely, beauty-making parts. 