A book review of an interesting approach to consciousness:-"Consciousness, then, is "integrated information"—"the information generated by the whole above and beyond its parts." Drawing on the area of mathematics known as information theory, Mr. Tononi has devised a set of equations that capture an organism's levels of differentiation (the ability to distinguish many states) and integration (communication across the system). His final measure for the degree of consciousness—a single number—is denoted by the Greek letter phi. Whether the theory is correct remains to be seen, but it is the first of its kind to rigorously define a metric for such an elusive quality."-http://online.wsj.com/article/SB10000872396390443816804578004260864176392.html?KEYWORDS=David+Eagleman-Still 'elusive' to me