Organon §141
The best provings are those that the physician employs upon himself.
Of all the provings of the pure actions of simple medicines in altering the human condition, and of the artificial disease states and symptoms that they engender in the healthy person, the most excellent provings remain those that the healthy, unprejudiced, conscientious and fine-feeling physician employs upon himself, with all the care and caution taught here. He knows [is aware] with the greatest certainty that which he has perceived in himself. 163
Comment
163 These self-provings have other irreplaceable advantages for the physician.
1. First of all, the great truth becomes an undeniable fact for him, that what is medicinal about all medicines (wherein their curative power rests) lies in the condition-alterations undergone by means of the self-proven medicines and in the disease states self-experienced by means of these medicines.
2. By means of such remarkable observations, he will develop an understanding appreciation of his own sensibilities, of his mode of thinking and emotions which is the basis [basic wesen] of all true wisdom, gnwqi seaton [know thyself].
3. By observing himself so closely, he will develop into a good observer, [a skill in which] no physician dare be lacking. None of the observations we make on others are nearly as appealing as those we make on ourselves.
4. The observer of others must always worry lest the prover of a medicine has not felt distinctly just what he says, nor stated and characterized his feelings with the exactly fitting expression. There is always a lingering doubt as to whether the physician is not being at least partly deceived. This insurmountable obstacle to the discernment of truth in the inquiry into the artificial disease symptoms of medicines in others falls entirely by the wayside in self-provings. The self-prover is aware, with certainty, of what he has felt.
5. Each self-proving is a new impetus for the physician in the investigation of the powers of several medicines. Thus, by continuing to observe himself (the one person who will not deceive him and upon whom he can most rely) the physician becomes more and more practiced in the art of observing, which is of such importance to him. He will do these self-provings all the more eagerly since they promise the knowledge of the mostly still missing implements for cure [i.e. , proven medicines], according to their true worth and meaning, and without deceiving him.
Let him not imagine that such small illnesses from taking proving medicines are generally detrimental to his health. On the contrary, experience teaches that, through the various attacks on the healthy condition, the prover's organism only becomes the more practiced in warding off everything from the external world that is inimical to his body, along with all the artificial and natural disease malignities. By means of such moderate self-provings with medicines, the prover's organism also becomes more seasoned [hardened] against everything that is detrimental. His health becomes more invariable; he becomes more robust, as all experience teaches.