in the ears or taste in the mouth or smell in the nose, or any other perceptible heat of fiery quality that warms the breast or any other part of the body, or any other thing that can be felt by a bodily sense, even if it is not so refreshing and agreeable, all this is not contemplation or observation; but in respect of the spiritual virtues, and those of celestial perception and love towards God, which accompany true contemplation, only evil secondary matters, even if they appear to be laudable and good. All such kinds of sensation may be good if produced by a good angel, but may, however, proceed in a deceptive manner, from the impositions of a bad angel, if he disguises himself as an angel of light. For the devil can imitate in bodily sensations exactly the same things that a good angel can accomplish. Indeed, just as the good angels come with light, so can the devil do also. And just as he can fabricate this in things that appear to the eyes, so he can bring it to pass in the other senses. The man who has perceived both can best say which is good and which is evil. But whoever knows neither or only one, can very easily be deceived.” Externally, in the sense quality, they are all similar, but internally they are very different. And therefore we should not too strongly desire them, nor lightly maintain that the soul can distinguish between the good and evil by the spirit of difference, so that it may not be deceived. As St. John says: “Believe not every spirit, but prove it first whether it be of God or not.” And to know whether the perception of the bodily sense is good or evil, Hitton gives the following rule: