With the dawn of the modern era there came a new interest in nature and the human mind. There was a withdrawal of attention from the supernatural to the natural, from the eternal to the temporal, from the divine to the human. This world with its interests came to its own. The secrets of nature were studied; its facts gathered; its laws formulated; its powers utilized; and its beauties appreciated. And the greater secrets of the human mind, too, were eagerly studied. The ideas of the mind were examined to discover whether they were innate or acquired; the relation of the data of the senses to the structure and the function of the mind was noted that the rise of knowledge might be learned; the legitimacy of the use of the categories of thought to interpret nature and the validity of our knowledge was called in question; and aspects of experience and powers of mind other than the distinctively rational came in for new appraisal.