It is the mark of an educated mind to expect that amount of exactness which the nature of the particular subject admits. It is equally unreasonable to accept merely probable conclusions from a mathematician and to demand strict demonstration from an orator.
In seeking for justice men seek for the mean or neutral, for the law is the mean. Again, customary laws have more weight, and relate to more important matters, than written laws, and a man may be a safer ruler than the written law, but not safer than the customary law.
There is an ideal of excellence for any particular craft or occupation; similarly there must be an excellent that we can achieve as human beings. That is, we can live our lives as a whole in such a way that they can be judged not just as excellent in this respect or in that occupation, but as excellent, period. Only when we develop our truly human capacities sufficiently to achieve this human excellent will we have lives blessed with happiness.
It is also in the interests of a tyrant to make his subjects poo...the people are so occupied with their daily tasks that they have no time for plotting.
If every tool, when ordered, or even of its own accord, could do the work that befits it... then there would be no need either of apprentices for the master workers or of slaves for the lords.