Chapter 16.—It is Not Essential to Man’s Happiness that He Should Know the Causes of Physical Convulsions; But It Is, that He Should Know the Causes of Good and Evil. Now, in view of these considerations, when we are pleased with that line of Maro, “Happy the man who has attained to the knowledge of the causes of things,” 1109 we should not suppose that it is necessary to happiness to know the causes of the great physical convulsions, causes which lie hid in the most secret recesses of nature’s kingdom, “whence comes the earthquake whose force makes the deep seas to swell and burst their barriers, and again to return upon themselves and settle down.” 1110 But we ought to know the causes of good and evil as far as man may in this life know them, in order to avoid the mistakes and troubles of which this life is so full. For our aim must always be to reach that state of happiness in which no trouble shall distress us, and no error mislead us. If we must know the causes of physical convulsions, there are none which it concerns us more to know than those which affect our own health. But seeing that, in our ignorance of these, we are fain to resort to physicians, it would seem that we might bear with considerable patience our ignorance of the secrets that lie hid in the earth and heavens. 1109     Virgil, Georgics , ii. 490. 1110     Ibid