Logic has attained in our century a development incomparably greater
than in any past age of its long history, and this has led to such an
enrichment and proliferation of its aspects, that the problem of some
kind of unified recom- prehension of this discipline seems nowadays
unavoidable. This splitting into several subdomains is the natural
consequence of the fact that Logic has intended to adopt in our century
the status of a science. This always implies that the general optics,
under which a certain set of problems used to be con- sidered, breaks
into a lot of specialized sectors of inquiry, each of them being
characterized by the introduction of specific viewpoints and of
technical tools of its own. The first impression, that often accompanies
the creation of one of such specialized branches in a diSCipline, is
that one has succeeded in isolating the 'scientific core' of it, by
restricting the somehow vague and redundant generality of its original
'philosophical' configuration. But, after a while, it appears that some
of the discarded aspects are indeed important and a new specialized
domain of investigation is created to explore them. By follOwing this
procedure, one finally finds himself confronted with such a variety of
independent fields of research, that one wonders whether the fact of
labelling them under a common denomination be nothing but the contingent
effect of a pure historical tradition.