Paracelsus

Seeking for truth, I considered with myself that if there were no teachers of medicine in this world, how would I set to learn the art? No otherwise than in the great book of nature, written with the finger of God ... I am accused and denounced for not having entered in at the right door of art. But which is the right one? Galen, Avicenna, Mesue, Rhasis, or honest nature? I believe, the last! Through this door I entered, and the light of nature, and no apothecary's lamp directed me on my way.