Book excerpt: Having imagined a machine-like world, scientists now haunt this machine uneasily. Their plight is paradoxical: they have realized their world only through intense mental effort, yet this effort finds no legitimate place in the world it so painstakingly comprehends. It seems "objectivity" only comes at a cost. Why, for example, is science unable to describe a smile? Why is the moral life of a physicist regarded as his or her own private affair? This exclusion of human qualities from science has practical as well as theoretical consequences. If we systematically imagine a world in which human beings don't exist, we will eventually create a world in which they cannot exist. Reclaiming the human sources of scientific insight, the authors of this book restore the scientist to the world given by science and celebrate the joyous marriage of sense and thought.