After a behavioristic hiatus of over half a century, American psychologists in the 1960s began, at first tentatively, to return consciousness to its former central position of concern. Because of this long period during which the use of the term was not allowed, we lost contact with the historical roots of the several different, but legitimate, definitions of consciousness. Today, we find psychologists of a wide variety of orientations using this word and assuming that its meaning is the same for others as it is for them. As William James pointed out in his Pragmatism (1907), many interminable quarrels continue because a key word in the dispute has two meanings that are incompatible. In most cases this incompatibility is quite real, for, as James says, the "practical consequences' may be entirely different according to which meaning is followed.