Vastness of the field of painting: All that is visible is included in the science of painting.
Defence of Painting
4.
With due lamentation Painting complains that it has been expelled from the liberal arts, because it is the true daughter of nature and is practised by means of the most worthy of the senses. Whence wrongly, O writers, you have excluded painting from the liberal arts, since it not only includes in its range the works of nature, but also infinite things which nature never created.
5.
Because writers have had no knowledge of the science of painting, they have not been able to describe its gradations and parts, and since painting itself does not reveal itself nor its artistic work in words, it has remained, owing to ignorance, behind the sciences mentioned above, but it has thereby lost nothing of its divinity. And truly it is not without reason that men have failed to honour it, because it does honour to itself without the aid of the speech of others, just as do the excellent works of nature. And if the painters have not described the art of painting, and reduced it to a science, the fault must not be imputed to painting and it is no less noble on that account, since few painters profess a knowledge of letters, as their life would not be long enough for them to acquire such knowledge. Therefore we ask, Is the virtue of herbs, stones and plants non-existent because men have been ignorant of it? Certainly not; but we will say that these herbs remained noble in themselves without the aid of human tongues or letters.
Painting
6.
A science is more useful in proportion as its fruits are more widely understood, and thus, on the other hand, it is less useful in proportion as it is less widely understood. The fruits of painting can be apprehended by all the populations of the universe because its results are subject to the power of sight, and it does not pass by the ear to the brain, but by the same channel by which sight passes. Therefore it needs no interpreters of diverse tongues, as letters do, and it has instantly satisfied the human race in the same manner as the works of nature have done. And not only the human race, but other animals; as was shown in a picture representing the father of a family to whom little children still in the cradle gave caresses, as did the dog and the cat in the same house; and it was a wonderful thing to see such a sight.
7.