The Complete Aristotle (eng.)

should have the supreme
power, and that mankind should obey him, not in turn, but always.
These are the conclusions at which we arrive respecting royalty and
its various forms, and this is the answer to the question, whether
it is or is not advantageous to states, and to which, and how.
XVIII
    We maintain that the true forms of government are three, and
that the best must be that which is administered by the best, and
in which there is one man, or a whole family, or many persons,
excelling all the others together in virtue, and both rulers and
subjects are fitted, the one to rule, the others to be ruled, in
such a manner as to attain the most eligible life. We showed at the
commencement of our inquiry that the virtue of the good man is
necessarily the same as the virtue of the citizen of the perfect
state. Clearly then in the same manner, and by the same means
through which a man becomes truly good, he will frame a state that
is to be ruled by an aristocracy or by a king, and the same
education and the same habits will be found to make a good man and
a man fit to be a statesman or a king.
    Having arrived at these conclusions, we must proceed to speak of
the perfect state, and describe how it comes into being and is
established.

Politics, Book IV
    Translated by Benjamin Jowett
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I
    In all arts and sciences which embrace the whole of any subject,
and do not come into being in a fragmentary way, it is the province
of a single art or science to consider all that appertains to a
single subject. For example, the art of gymnastic considers not
only the suitableness of different modes of training to different
bodies (2), but what sort is absolutely the best (1); (for the
absolutely best must suit that which is by nature best and best
furnished with the means of life), and also what common form of
training is adapted to the great majority of men (4). And if a man
does not desire the best habit of body, or the greatest skill in
gymnastics, which might be attained by him, still the trainer or
the teacher of gymnastic should be able to impart any lower degree
of either (3). The same principle equally holds in medicine and
shipbuilding, and the making of clothes, and in the arts
generally.
    Hence it is obvious that government too is the subject of a
single science, which has to consider what government is best and
of what sort it must be, to be most in accordance with our
aspirations, if there were no external impediment, and also what
kind of government is adapted to particular states. For the best is
often unattainable, and therefore the true legislator and statesman
ought to be acquainted, not only with (1) that which is best in the
abstract, but also with (2) that which is best relatively to
circumstances. We should be able further to say how a state may be
constituted under any given conditions (3); both how it is
originally formed and, when formed, how it may be longest
preserved; the supposed state being so far from having the best
constitution that it is unprovided even with the conditions
necessary for the best; neither is it the best under the
circumstances, but of an inferior type.
    He ought, moreover, to know (4) the form of government which is
best suited to states in general; for political writers, although
they have excellent ideas, are often unpractical. We should
consider, not only what form of government is best, but also what
is possible and what is easily attainable by all. There are some
who would have none but the most perfect; for this many natural
advantages are required. Others, again, speak of a more attainable
form, and, although they reject the constitution under which they
are living, they extol some one in particular, for example the
Lacedaemonian. Any change of government which has to be introduced
should be one which men, starting from their existing
constitutions, will be both willing and able to adopt, since there
is quite as much trouble in the reformation of an old constitution
as in the establishment of a new one, just as to unlearn is as hard
as to learn. And therefore, in addition to the qualifications of
the statesman already mentioned, he should be able to find remedies
for the defects of existing constitutions, as has been said before.
This he cannot do unless he knows how many forms of government
there are. It is often supposed that there is only one kind of
democracy and one of oligarchy. But this is a mistake; and, in
order to avoid such mistakes, we must