"Know that man makes great discoveries concerning future and hidden things, which are despised and scoffed at by the ignorant who do not realize what nature can accomplish by value of her spirit. Thus, the uncertain arts are in such a state now that a new generation must come, full of prophetic or sibylline spirit, which will awaken and direct the skills and arts. The arts of this kind are quite old, and enjoyed great reputation among the ancient. They are kept secret and taught secretly. For the students of these arts devoted their time to contemplation and inner faith, and by such means discovered and proved many great things. But the men of today have no longer such capacity for imagination and faith; today their minds are exclusively concerned with things that are pleasant to the flesh and the blood; only what the flesh and the blood want and desire is being studied, that alone is still being practiced. These arts are uncertain today because man is uncertain in himself. For he who is not certain in himself cannot be certain in his actions; a sceptic can never create anything enduring, nor can anyone who serves only the body accomplish true spiritual works."
– Paracelsus, Astronomia Magna , 1537-38.