But as I am certain that no one has any knowledge of his soul except through thought, or through the inner sensation of all that takes place in his mind, I am convinced as well that if someone wishes to consider the nature of the soul, he need only consult this inner sensation, which continually represents to him what he is, and he should not fancy, contrary to his own consciousness, that the soul is an invisible fire, or subtle air, or a hannony, or some other such thing.