DEFINITIONS OF HAPPINESS.
1. The (Aristotelian) ideal of living well and happiness are (practically) identical. Should we, on that account, grant even to animals the privilege of achieving happiness? Why might we not say that they live well, if it be granted them, in their lives, to follow the course of nature, without obstacles? For if to live well consist either in pleasure (pleasant passions, as the Epicureans taught), or in realizing one’s own individual aim (the Stoic ideal), then this living well is, in either case, possible for animals, who can both enjoy pleasure, and accomplish their peculiar aim. Thus singing birds live a life desirable for them, if they enjoy pleasure, and sing conformably to their nature. If further we should define happiness as achieving the supreme purpose towards which nature aspires (the Stoic ideal), we should, even in this case, admit that animals share in happiness when they accomplish this supreme purpose. Then nature arouses in them no further desires, because their whole career is completed, and their life is filled from beginning to end.
WHETHER PLANTS MAY BE TERMED HAPPY.
There are no doubt some who may object to our admitting to happiness living beings other than man. They might even point out that on this basis happiness could not be refused to even the lowest beings, such as plants: for they also live, their life also has a purpose, by which they seek to fulfil their development. However, it would seem rather unreasonable to say, that living beings other than humans cannot possess happiness by this mere reason that to us they seem pitiable. Besides, it would be quite possible to deny to plants what may be predicated of other living beings, on the grounds that plants lack emotion. Some might hold they are capable of happiness, on the strength of their possessing life, for a being that lives can live well or badly; and in this way we could say that they possess or lack well-being, and bear, or do not bear fruits. If (as Aristippus thought), pleasure is the goal of man, and if to live well is constituted by enjoying it, it would be absurd to claim that no living beings other than man could live well. The same argument applies if we define happiness as (a state of imperturbable tranquility, by Epicurus called) ataraxy; or as (of the Stoic ideal) living conformably to nature.