It may be a distasteful notion, this bringing-down of happiness so low as to the animal world — making it over, as then we must, even to the vilest of them and not withholding it even from the plants, living they too and having a life unfolding to a Term.
But, to begin with, it is surely unsound to deny that good of life to animals only because they do not appear to man to be of great account. And as for plants, we need not necessarily allow to them what we accord to the other forms of life, since they have no feeling. It is true people might be found to declare prosperity possible to the very plants: they have life, and life may bring good or evil; the plants may thrive or wither, bear or be barren.
No: if Pleasure be the Term, if here be the good of life, it is impossible to deny the good of life to any order of living things; if the Term be inner-peace, equally impossible; impossible, too, if the good of life be to live in accordance with the purpose of nature.