In the later middle ages, however, philosophy gradually succeeded in emancipating itself so entirely from theology, that when the Renaissance came, and a large body of heathen thought was introduced into the current of European life by means of ancient literature, a third crisis occurred. The independence passed into open revolt, and, fostered by political confusion and material luxury, expressed itself in a literature of unbelief. The mental awakening which had commenced in art and extended to literature paved the way for a spiritual awakening. The Reformation itself, though the product of a deep consciousness of spiritual need, an emancipation of soul as well as mind, is nevertheless a special instance of the same dissolution of mediæval life, and must therefore be regarded as belonging to the same general movement of free thought, though not to that sceptical form of it which comes within the field of our investigation. For Protestantism, though it be scepticism in respect of the authority of the traditional teaching of the Church, yet reposes implicitly on an outward authority revealed in the sacred books of holy Scripture, and restricts the exercise of freedom within the limits prescribed by this authority; whereas scepticism proper is an insurrection against the outward authority or truth of the inspired books, and reposes on the unrevealed, either on consciousness or on science. The one is analogous to a school of art which desires to reform itself by the use of ancient models; the other to one which professes to return to an unassisted study of nature. The spiritual earnestness which characterized the Reformation prevented the changes in religious belief from developing into scepticism proper; and the theology of the Reformation is accordingly an example of defence and reconstruction as well as of revulsion.