The hypersensitivity and instability of the patient have certain habitual causes. The first is grief, often caused by some severe shock, such as the loss of a dear relation or friend or a disappointment in love. Another cause is nervous overstrain, such as is seen in intellectual people who do not have enough physical exercise and who are very sensitive to tobacco smoke and to coffee.
Paracelsus also states that he who wants to know man must look upon him as a whole and not as a patched up piece of work. If he finds a part of the human body diseased he must look for the causes which produce the disease and not merely treat the external effects. Philosophy-the true perception and understanding of cause and effect-is the mother of the physician and explains the origin of all his diseases.