"Great as Bacon was, he was far from being free from the mistakes and prejudices of those who went before him. Even some of the most wild and absurd opinions of the antients have the sanction of his approbation and authority. He does not hesitate to assent to an opinion... that visual rays proceed from the eye; giving this reason for it, that every thing in nature is qualified to discharge its proper functions by its own powers, in the same manner as the sun, and other celestial bodies. He acknowledges, however, that the presence of light, as well as several other circumstances, is necessary to vision."