The concept of consciousness is familiar to us all, but it may be the most mysterious feature of our existence. These questions have occupied philosophers and artists ranging from the writings of Kant and Hegel to movies like Arnold Schwarzenegger's Total Recall . Scientists are now finally glimpsing brain activity that they believe is associated with consciousness, yet many people question whether we can ever have real answers.
Consciousness poses probably the greatest challenge to reductionist approaches.
The history of science is littered with problems thought to be insoluble and immune to a reductionist approach. Heat, related to the movement of molecules, is one example of a phenomenon people thought could never be explained. Until people understood what molecules were and that faster-moving molecules caused higher temperatures, they found it inconceivable that temperature could ever be explained. Genes and DNA are a similar example brought up by Dr. Christof Koch, a neuroscientist from the California Institute of Technology who is currently collaborating with DNA structure co-discoverer Francis Crick on some of his work. Koch showed a quote from a book published in 1916 and explained that, back then, people couldn't conceive how chromosomes, seemingly indistinguishable from each other, could convey all the properties of life.