There is nothing original in this position.  It was characteristic of decadent scholasticism, it squared with Luther’s exaggerations about the impotence of reason in fallen man, and Pascal had given his own highly personal twist to it.  Bayle has been hailed as a forerunner of Voltairean scepticism.  It would be truer to say that a Voltairean sceptic could read Bayle’s discussions in his own sense and for his own purposes if he wished.  But Bayle was not a sceptic.  It is hard to say what he was; his whole position as between faith and reason is hopelessly confused.  He was a scholar, a wit, and a philosophical sparring-partner of so perfectly convenient a kind that if we had not evidence of his historical reality, we might have suspected Leibniz of inventing him.

In the first edition of his Dictionary, under the article ‘Rorarius’, Bayle gave a very fair account of Leibniz’s doctrine concerning the souls of animals, as it could be collected from his article in the Journal des Savants, 27 June 1695.  He then proceeded to comment upon it in the following terms: 

’There are some things in Mr. Leibniz’s hypothesis that are liable to some difficulties, though they show the great extent of his genius.  He will have it, for example, that the soul of a dog acts independently of outward bodies; that it stands upon its own bottom, by a perfect spontaneity_ with respect to itself, and yet with a perfect conformity to outward things_....  That its internal perceptions arise from its original constitution, that is to say, the representative constitution (capable of expressing beings outside itself in relation to its organs) which was bestowed upon it from the time of its creation, and makes its individual character (Journal des Savants, 4 July 1695).  From whence it results that it would feel hunger and thirst at such and such an hour, though there were not any one body in the universe, and though nothing should exist but God and that soul.  He has explained (Histoire des Ouvrages des Savants, Feb. 1696) his thought by the example of two pendulums that should perfectly agree:  that is, he supposes that according to the particular laws which put the soul upon action, it must feel hunger at such an hour; [36] and that according to the particular laws which direct the motion of matter, the body which is united to that soul must be modified at that same hour as it is modified when the soul is hungry.  I will forbear preferring this system to that of occasional causes till the learned author has perfected it.  I cannot apprehend the connexion of internal and spontaneous actions which would have this effect, that the soul of a dog would feel pain immediately after having felt joy, though it were alone in the universe.  I understand why a dog passes immediately from pleasure to pain when, being very hungry and eating a piece of bread, he is suddenly struck with a cudgel.  But I cannot apprehend that his soul should be so framed that at the very moment of his being beaten he should feel pain though he were not beaten, and though he should continue to eat bread without any trouble or hindrance.  Nor do I see how the spontaneity of that soul should be consistent with the sense of pain, and in general with any unpleasing perceptions.