"To be scientific, that is to know what one knows and what one does not know; unscientific is dogmatic knowledge. To be scientific is to know with reasons; to accept ready-made opinions is unscientific. Scientific is the knowledge with the consciousness of the respectively determined limits of the knowledge; unscientific is all total knowledge, as if one knew in the whole. Scientific is boundless criticism and self-criticism, the advancing questioning; unscientific is the concern that doubt could paralyze. Scientific is the methodical course, which step by step on the ground of experience penetrates to the decision; unscientific is the play of multiple opinions and possibilities and the murmuring."