That was an excellent observation, Measure the stone by the
mason's rule, not the rule by the stone.[252] But the Stoics, not
applying dogmas to facts but facts to their own preconceived opinions,
and forcing things to agree that do not by nature, have filled
philosophy with many difficulties, the greatest of which is that all men
but the perfect man are equally vicious, which has produced the enigma
called progress, one little short of extreme folly, since it makes those
who have not at once under its guidance given up all passions and
disorders equally unfortunate as those who have not got rid of a single
vile propensity. However they are their own confuters, for while they
lay down in the schools that Aristides was as unjust as Phalaris, and
Brasidas as great a craven as Dolon, and Plato actually as senseless as
Meletus, in life and its affairs they turn away from and avoid one class
as implacable, while they make use of the others and trust them in most
important matters as most worthy people.

Sec. III. But we who see that in every kind of evil, but especially in a
disordered and unsettled state of mind, there are degrees of more and
less (so that the progress made differs in different cases, badness
abating, as a shadow flees away, under the influence of reason, which
calmly illuminates and cleanses the soul), cannot consider it
unreasonable to think that the change will be perceived, as people who
come up out of some ravine can take note of the progress they make
upwards. Look at the case from the following point of view first. Just
as mariners sailing with full sail over the gaping[253] ocean measure
the course they have made by the time they have taken and the force of
the wind, and compute their progress accordingly, so anyone can compute
his progress in philosophy by his continuous and unceasing course, by
his not making many halts on the road, and then again advancing by leaps
and bounds, but by his quiet and even and steady march forward guided by
reason. For the words of the poet, "If to a little you keep adding a
little, and do so frequently, _it will soon be a lot_,"[254] are not
only true of the increase of money, but are universally applicable, and
especially to increase in virtue, since reason invokes to her aid the
enormous force of habit. On the other hand the inconsistencies and
dulnesses of some philosophers not only check advance, as it were, on
the road, but even break up the journey altogether,