“There is upon this earth nothing more noble and more capable of giving perfect happiness than a true knowledge of nature and its foundation. Such a knowledge produces a valuable physician, but it should be a part of his constitution and not an artificial fabric attached to him like a coat; he must himself be born out of the fountain of that philosophy which cannot be acquired by artificial means.” (See: “De Generatione hominum,” I. Preface.) A knowledge based upon the opinion or experience of another is merely a belief, but does not constitute real knowledge. Books and lectures may serve to give us advice, but they cannot endow us with the power of knowing the truth; they may serve us as useful guides, but a belief in the statements of others should not be mistaken for self-knowledge, such as arises only from the self-recognition of truth, and which by means of a love of the truth ought to be cultivated above all else. To this realm of Philosophy belong all the natural sciences referring to external phenomena, in the knowledge of which a great deal of progress seems to have been made since the time of Paracelsus. To this phenomenal science belongs the anatomy, physiology, the chemistry of the physical body and all that concerns the interrelations of the phenomena existing in the grand phantasmagoria of living and corporeal images called the sensual world. But behind this sensual world there is a more interior super-sensual world, ignored by popular science, of which the former is the external expression; the processes taking place in this interior light of nature, mirror themselves in the light of the external world, and those souls whose inner perceptions have become developed in consequence of an awakening of the “inner man,” do not require the observation of external phenomena for the purpose of drawing inferences in regard to their internal causes, because they know the interior causes and processes and also the external appearances which they will produce. Thus there is an external and an internal medical science, a science concerning the astral and a science concerning the physical body of man. The former occupies itself with the patient, the latter, so to say, with the clothes which he wears.