Causal influences in the real world occurring on evolutionary, developmental, and functional timescales are characterised by a combination of bottom up and top down effects. Digital computers give very clear examplars of how this happens, and it is crucial to brain functioning. There are five different distinct classes of top down effects, the key one leading to the existence of complex systems being adaptive selection. The case will be made that while bottom-up self-assembly can attain a certain degree of complexity, truly complex systems such as life can only come into being if top-down processes come into play in addition to bottom up processes. They allow genuine emergence to occur, based in multiple realisability at lower levels of higher level structures and functions.
Prof GEORGE ELLIS FRS is Professor Emeritus at the University of Cape Town, specialising in general relativity theory and cosmology, but also working in complexity theory and the way the mind works. His honors include the Star of South Africa medal awarded by President Nelson Mandela, the Order of Mapungubwe awarded by President Thabo Mbeki, honorary degrees from UCT and 3 other universities, and the Templeton Prize. He wrote The Large Scale Structure of Spacetime with Stephen Hawking, and On the Moral Nature of the Universe with Nancey Murphy.