The motive is not so much humanity to the slave, of which there are hardly any traces (although Plato allows that many in the hour of peril have found a slave more attached than members of their own family), but the self-respect which the freeman and citizen owes to himself (compare Republic).

If they commit crimes, they are doubly punished; if they inform against illegal practices of their masters, they are to receive a protection, which would probably be ineffectual, from the guardians of the law; in rare cases they are to be set free.

Plato still breathes the spirit of the old Hellenic world, in which slavery was a necessity, because leisure must be provided for the citizen.
The education propounded in the Laws differs in several points from that of the Republic.

Plato seems to have reflected as deeply and earnestly on the importance of infancy as Rousseau, or Jean Paul (compare the saying of the latter--'Not the moment of death, but the moment of birth, is probably the more important').

He would fix the amusements of children in the hope of fixing their characters in after-life.