In the first chapter of his De Christiana Religione, Ficino uses various arguments to prove that the worship of God is what sets man apart from the other animals. Worth noting here, again, is the fact that Ficino does not appeal to any Medieval authorities to make his claims. Also interesting is Ficino’s appeal to a sort of religious “common sense” rather than producing a deductive proof for the existence of God.
Ficino makes quite a few arguments in defense of his thesis but I will summarize some of the most pertinent ones:
Religion is profoundly and rightly unique to man.
We see that the individual qualities of human kind sometimes appear in certain animals, at least according to a certain likeness [to humans], with the exception of religion. The fact that no animal exhibits the evidence of religion is in accordance with the fact that the upward intension of the mind toward God the King of heaven is unique to us, just as a body standing upward toward heaven is unique to us. Therefore, divinely inspired worship is completely natural to man in the same way that neighing is unique to a horse and barking is unique to a dog.
If some more curious individual, however, asserts that some animals sometimes venerate the heavens above them, which I do not believe in the least, the Platonists shall respond to them that animals of this kind, whether they are doing something entirely different at the moment when they appear to be worshipping, or if they pay honor to the heavens by chance, nevertheless they do not know what they are doing, or if they do know, then they also share in intelligence and immortality. But, to return to the topic at hand, that is man the most perfect animal, that very peculiar quality by which he is most perfect – on the one hand he has great power and on the other hand he is different from lower creatures because of this perfection – is this, that he is united to the divine.
Again, if man is the most perfect of the mortal animals, inasmuch as he is man, then he is the most perfect of all especially because of the quality which is unique to him and not common to other animals, which is religion. Therefore, man is the most perfect [of the mortal animals] by means of religion. If religion were useless, then on the other hand man would be the most flawed of all because he would be completely insane [dementissimus] and unhappy [miserrimus] as a result of it. Accordingly, it is very much the case that human beings truly discard many things that are suitable and assume many things that are unsuitable for temporal life either because of their love for God or fear of him. But, no other animal abstains from present goods for the sake of worshipping God and the expectation of future [goods]. In addition, it is unique to us that the sting of knowledge constantly pricks us and the fear of both divine vengeance and inferior things most bitterly vexes us.
If, as we have said, religion is useless then no animal is more insane [dementius] and unhappy than man. If this were the case, man would be the most flawed of all the animals because of religion though just a little while ago he appeared to be more perfect than all of them. Man cannot, however, suffer contraries to exist throughout one of his parts so that, in relation to that part he might be at the same time both very perfect and very much flawed. Therefore, religion is true especially because man cannot lose his intellect and raison d’être as a result of it, 1 just as fire cannot even come close to becoming very cold, because religion clings to the most wise and blessed God alone. Neither is God, who is the highest Truth and Goodness, able to deceive humanity, his own offspring. The natural and common opinion concerning God was inserted in us by God at the general production and beginning of the natural world.
Besides, we ought to remember that any prophecy is true which somehow is produced by the whole species of animals because it is produced by the instigation [instinctu] of both the universal and particular nature. Many reptiles slithering out of the bowels of the earth foretell of fog. Many flocks of crows in the evening flying from a certain region of the sky forecast the wind. There are also many other events of this kind. The prophecy [vaticinium] that is common to man also shows that religion is true, for everyone everywhere worships God for the sake of the future life. So it is true that God is going to provide another life for us if only the most perfect of the animal species holds that the truest judgment for it is the judgment that is the most natural of all. But such an assertion regarding religion appears to be true not only by the fact that it is man’s alone but also that all the opinions, feelings, and customs of men change while religion does not. 2 If anyone, therefore, is found inwardly lacking all religion, since he is contrary to the nature of the human species, either he had a monstrous beginning or he was polluted by contact with another monstrous occurrence. 3