The Complete Aristotle (eng.)

and
fathers and mothers from sometimes recognizing one another; for
children are born like their parents, and they will necessarily be
finding indications of their relationship to one another.
Geographers declare such to be the fact; they say that in part of
Upper Libya, where the women are common, nevertheless the children
who are born are assigned to their respective fathers on the ground
of their likeness. And some women, like the females of other
animals—for example, mares and cows—have a strong tendency to
produce offspring resembling their parents, as was the case with
the Pharsalian mare called Honest.
IV
    Other evils, against which it is not easy for the authors of
such a community to guard, will be assaults and homicides,
voluntary as well as involuntary, quarrels and slanders, all which
are most unholy acts when committed against fathers and mothers and
near relations, but not equally unholy when there is no
relationship. Moreover, they are much more likely to occur if the
relationship is unknown, and, when they have occurred, the
customary expiations of them cannot be made. Again, how strange it
is that Socrates, after having made the children common, should
hinder lovers from carnal intercourse only, but should permit love
and familiarities between father and son or between brother and
brother, than which nothing can be more unseemly, since even
without them love of this sort is improper. How strange, too, to
forbid intercourse for no other reason than the violence of the
pleasure, as though the relationship of father and son or of
brothers with one another made no difference.
    This community of wives and children seems better suited to the
husbandmen than to the guardians, for if they have wives and
children in common, they will be bound to one another by weaker
ties, as a subject class should be, and they will remain obedient
and not rebel. In a word, the result of such a law would be just
the opposite of which good laws ought to have, and the intention of
Socrates in making these regulations about women and children would
defeat itself. For friendship we believe to be the greatest good of
states and the preservative of them against revolutions; neither is
there anything which Socrates so greatly lauds as the unity of the
state which he and all the world declare to be created by
friendship. But the unity which he commends would be like that of
the lovers in the Symposium, who, as Aristophanes says, desire to
grow together in the excess of their affection, and from being two
to become one, in which case one or both would certainly perish.
Whereas in a state having women and children common, love will be
watery; and the father will certainly not say ‘my son,’ or the son
‘my father.’ As a little sweet wine mingled with a great deal of
water is imperceptible in the mixture, so, in this sort of
community, the idea of relationship which is based upon these names
will be lost; there is no reason why the so-called father should
care about the son, or the son about the father, or brothers about
one another. Of the two qualities which chiefly inspire regard and
affection—that a thing is your own and that it is your only
one-neither can exist in such a state as this.
    Again, the transfer of children as soon as they are born from
the rank of husbandmen or of artisans to that of guardians, and
from the rank of guardians into a lower rank, will be very
difficult to arrange; the givers or transferrers cannot but know
whom they are giving and transferring, and to whom. And the
previously mentioned evils, such as assaults, unlawful loves,
homicides, will happen more often amongst those who are transferred
to the lower classes, or who have a place assigned to them among
the guardians; for they will no longer call the members of the
class they have left brothers, and children, and fathers, and
mothers, and will not, therefore, be afraid of committing any
crimes by reason of consanguinity. Touching the community of wives
and children, let this be our conclusion.
V
    Next let us consider what should be our arrangements about
property: should the citizens of the perfect state have their
possessions in common or not? This question may be discussed
separately from the enactments about women and children. Even
supposing that the women and children belong to individuals,
according to the custom which is at present universal, may there
not be an advantage in having and using possessions in common?
Three cases are