No More Learning

The
Stoics, on the contrary, had chosen their supreme practical
principle quite rightly, making virtue the condition of the summum
bonum; but when they represented the degree of virtue required by
its pure law as fully attainable in this life, they not only
strained the moral powers of the man whom they called the wise
beyond all the limits of his nature, and assumed a thing that
contradicts all our knowledge of men, but also and principally they
would not allow the second element of the summum bonum, namely,
happiness, to be properly a special object of human desire, but made
their wise man, like a divinity in his consciousness of the excellence
of his person, wholly independent of nature (as regards his own
contentment); they exposed him indeed to the evils of life, but made
him not subject to them (at the same time           him also as
free from moral evil).