Vanini’s philosophy does not go very far; he admires the living energy of Nature; his reasonings were not deep, but were more of the nature of fanciful ideas. He always chose the dialogue form; and it is not evident which of the opinions stated are his own. He wrote commentaries on Aristotle’s works on Physics. We have two other works by Vanini, which are very rare. The one is styled: _Amphitheatrum æternæ providentiæ divino-magicum, christiano-physicum, nec non astrologo-catholicum, adversus veteres philosophos, Atheos, Epicureos, Peripateticos et Stoicos. Auctore Julio Cæsare Vanino, Lugd. 1615_; in this he gives a very eloquent account of all these philosophies and their principles, but the manner in which he refutes them is rather feeble. The second work is entitled “On the Wonderful Secrets of Nature, the Queen and Goddess of Mortals” (_De admirandis Naturæ, reginæ Deæque mortalium, arcanis libr. IV., Lutetiæ 1616_); it was printed “with the approval of the Sorbonne,” which at first found in it nothing “which contradicted and was hostile to the Catholic Apostolic and Roman religion.” It contains scientific investigations into various matters belonging to physics and natural history, and is also in dialogue form, without definite indication being given as to which of the characters is made the mouthpiece of Vanini’s own opinions. What one finds is assurances from him that he would believe this or that doctrine if he had not received Christian teaching. Vanini’s tendency, however, was towards naturalism; he showed that it is Nature that is the Deity, that all things had a mechanical genesis. He therefore explained the whole universe in its connection by efficient causes alone, not by final causes; but the statement of this is made in such a way that the writer does not give it as his own conclusion.[93]