The most general division of the writings of Plato, is into those of the
Sceptical kind, and those of they Dogmatical. In the former sort, nothing
is expressly either proved or asserted, some philosophical question only is
considered and examined; and the reader is left to himself to draw such
conclusions, and discover such truths as the philosopher means to
insinuate. This is done, either in the way of inquiry, or in the way of
controversy and dispute. In the way of controversy are carried on all such
dialogues, as tend to eradicate false opinions; and that, either indirectly,
by involving them in difficulties, and embarrassing the maintainers of them;
or directly, by confuting them. In the way of inquiry proceed those whose
tendency is to raise in the mind right opinions; and that either by exciting
to the pursuit of some part of wisdom, and showing in what manner to
investigate it; or by leading the way, and helping the mind forward in the
search. And this is effected by a process through opposing arguments.[23]

------------------
[23] It is necessary to observe that Plato in the Parmenides calls all
that part of his Dialectic, which proceeds through opposite arguments, an
exercise and wandering.
------------------

The dialogues of the other kind, the Dogmatical or Didactic, teach
explicitly some point of doctrine; and this they do either by laying it
down in the authoritative way, or by proving it in the ways of reason and
argument. In the authoritative way the doctrine is delivered, sometimes by
the speaker himself magisterially, at other times as derived to him by
tradition from wise men. The argumentative or demonstrative method of
teaching, used by Plato, proceeds in all the dialectic ways, dividing,
defining, demonstrating, and analysing; and the object of it consists in
exploring truth alone. According to this division is framed the following
scheme, or table:

DIALOGUES[24]

Sceptical Disputative Embarrassing Confuting Inquisitive Exciting Assisting
Dogmatical Demonstrative Analytical Inductional Authoritative Magisterial
Traditional

-----------------
[24]We have, given us by Diogenes Laertius, another division of the
characters, as he calls them, of Plato's writings, different from that
exhibited in the scheme above. This we have thought proper to subjoin, on
account of its antiquity and general reception.

Dialogues

Diadectic Speculative Physical Logical Practical Ethical Political
Inquisitive