Is Disease a belief? I answer it is, for an individual is to himself just what he thinks he is, and he is in his belief sick. If I believe I am sick, I am sick, for my feelings are my sickness, and my sickness is my belief, and my belief is my mind. Therefore all disease is in the mind or belief. Now as our belief or disease is made up of ideas, which are [spiritual] matter, it is necessary to know what beliefs we are in; for to cure the disease is to correct the error, and as disease is what follows the error, destroy the cause, and the effect will cease. How can this be done? By a knowledge of the law of harmony. To illustrate this law of harmony I must take some law that you will admit. I will take the law of mathematics. You hear of a mathematical problem, you wish to solve it; the answer is in the problem, the error is in it, the happiness and misery are also in it. Your error is the cause of your sickness or trouble. Now to cure your sickness or trouble, is to correct the error. If you knew the real state of things, you would not call on a person who knows no more than you do, if you knew that fact.
— Nov. 1859.
P. P. Quimby