Remember that desire contains in it the profession (hope) of obtaining that which you desire; and the profession (hope) in aversion (turning from a thing) is that you will not fall into that which you attempt to avoid: and he who fails in his desire is unfortunate; and he who falls into that which he would avoid, is unhappy. If then you attempt to avoid only the things contrary to nature which are within your power, you will not be involved in any of the things which you would avoid. But if you attempt to avoid disease or death or poverty, you will be unhappy.
Take away, then, aversion from all things which are not in our power, and transfer it to the things contrary to nature which are in our power. But destroy desire completely for the present. For if you desire anything which is not in our power, you must be unfortunate: but of the things in our power, and which it would be good to desire, nothing yet is before you. But employ only the power of moving toward an object and retiring from it; and these powers indeed only slightly and with exceptions and with remission.