What they call knowledge is, in effect, an act of faith

During the course of centuries mankind has become inured to a scientific outlook that is related to the phenomenal world and has come to accept the findings of astronomy, botany, zoology and medicine, for example, in the form in which they are presented in recognized schools or centres of learning. A chemist, for example, undertakes a piece of research in his laboratory. People have not the slightest understanding of the technique involved. The work is acclaimed and they unhesitatingly declare: “Here is truth, here is knowledge that makes no appeal to faith.” But what they call knowledge is, in effect, an act of faith.

Source: Rudolf Steiner – GA 243 – True/False Paths: Lecture Eleven: What is the Position in Respect of Spiritual Investigation and the Understanding of Spiritual Investigation? – Torquai, August 22, 1924