'We must also reflect that of desires some are natural, others are groundless; and that of the natural some are necessary as well as natural, and some natural only. And of the necessary desires some are necessary if we are to be happy, some if the body is to be rid of uneasiness, some if we are even to live. He who has a clear and certain understanding of these things will direct every preference and aversion toward securing health of body and tranquility of mind, seeing that this is the sum and end of a blessed life.'
- Epicurus, Letter to Menoeceus
The three kinds of desires are divided along lines of their ease to satisfy and their importance to our well-being. The category ‘natural and necessary desires’ encompasses desires for sustenance, protection from the elements, and anything else we would need to survive. They are relatively easy to satisfy and vital to our physical health. The category ‘natural and unnecessary desires’ encompasses all of those actions that are pleasurable and productive to our health, but which are not necessary to maintain our health. They are nonetheless aids to our health and mental well-being. I would include exercise/working out in this category along with the desire for friendships and romantic relationships. These are a bit harder to satisfy than natural and necessary desires. The desire for human contact itself could be considered a natural and necessary desire given the deleterious affects complete isolation has on mental and physical health. We are, after all, social animals. The category of groundless desires encompasses all vain and empty desires which are neither natural or necessary. By this I mean that their satisfaction is unnecessary to maintain our health and well-being and they do not aid our health and well-being. I would include in this category all the ornaments of wealth, the desire for popularity, fame, and fortune along with the desire to induce happiness through drugs or alcohol. Given that the average person will never obtain the objects of these desires, these desires are extremely difficult to satisfy and will most likely lead to despondency if you make your happiness dependent upon them. Substance abuse has its own set of dangers to mental and physical health on top of unhappiness. The aim of hedonists should be to direct their efforts towards those desires that secure physical, mental, and spiritual health. This would include all the natural and necessary desires and some of the natural and unnecessary desires. For instance, some relationships could be precluded if you believe that they wouldn’t be feasible in your current circumstances.