Organon §213

A remedy must be able to engender mental and emotional symptoms similar to those of the disease in order to cure it.

For this reason, one will never cure in accordance with nature, that is, one will never cure homeopathically unless:

1. one attends to the symptom of the mental and emotional alterations, together with the other symptoms, in every case of disease, even acute ones, and

2. for aid, one selects, from among the remedies, a disease potence that, along with the similarity of its other symptoms with those of the disease, is of itself capable of engendering a mental or emotional state similar to that of the disease. 188

Comment

188 Thus aconite will seldom or never produce either a rapid or permanent cure if the patient's emotional state is quiet and uniformly calm. Nux vomica will not cure if the patient has a mild and phlegmatic emotional state. Pulsatilla will not cure if the patient's emotional state is glad, cheerful and stubborn. Ignatia will not cure if the patient's emotional state is unchangeable and not inclined to fright or vexation.