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26

statement. I regret that the brevity of the course
forbids my illustrating it.

The beta part of the system of existential
graphs is distinguished from the
alpha-part by the presence of ligatures
in its graphs; and it is therefore natural
to think that the distinction between alpha-
possibility and beta possibility lies in the
latter's taking account of the relation of
identity. But it could easily be demonstrated
that this is not the truth of the
matter. The true distinction lies in the fact
that beta possibility takes account of
individuals, so that whereas in the
alpha part all the spots are regarded