Again, on the other hand, Zeno the Stoic thinks the end to be living according to virtue; and, Cleanthes, living agreeably to nature in the right exercise of reason, which he held to consist of the selection of things according to nature. And Antipatrus, his friend, supposes the end to consist in choosing continually and unswervingly the things which are according to nature, and rejecting those contrary to nature. Archedamus, on the other hand, explained the end to be such, that in selecting the greatest and chief things according to nature, it was impossible to overstep it. In addition to these, Panætius pronounced the end to be, to live according to the means given to us by nature. And finally, Posidonius said that it was to live engaged in contemplating the truth and order of the universe, and forming himself as he best can, in nothing influenced by the irrational part of his soul. And some of the later Stoics defined the great end to consist in living agreeably to the constitution of man. Why should I mention Aristo? He said that the end was indifference; but what is indifferent simply abandons the indifferent. Shall I bring forward the opinions of Herillus? Herillus states the end to be to live according to science. For some think that the more recent disciples of the Academy define the end to be, the steady abstraction of the mind to its own impressions. Further, Lycus the Peripatetic used to say that the final end was the true joy of the soul; as Leucimus, that it was the joy it had in what was good. Critolaus, also a Peripatetic, said that it was the perfection of a life flowing rightly according to nature, referring to the perfection accomplished by the three kinds according to tradition.