Before Darwin, natural theology both assumed the existence of God and used the appearance of function in nature to argue for the existence of God.[9][10] The English parson-naturalist John Ray stated that his intention was "to illustrate the glory of God in the knowledge of the works of nature or creation".[8] Natural theology presented forms of the teleological argument or argument from design, namely that organs functioned well for their apparent purpose, so they were well-designed, so they must have been designed by a benevolent creator. For example, the eye had the function of seeing, and contained features like the iris and lens that assisted with seeing; therefore, ran the argument, it had been designed for that purpose.[9][10][11]