Dreaming is defined by the following philosophers as: (1) For Plato, the manifestation of numerous irrational impulses that, while awake, would be under rational control. (2) For Aristotle,
the experience of images retained from waking experience. Dreams are usually bizarre because the images experienced during sleep are neither organized by our rational powers nor supported by ongoing sensory experience. That dreams sometimes correspond to future events was, for Aristotle, mere coincidence. However, because bodily processes are exaggerated in dreams, physicians can sometimes use dreams to detect the early signs of disease.