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teacher Democritos (ca. 460-ca. 370). Even if many of Aristotle's writings are lost,
the historical traditional of his lifework seems to be the first comprehensive system
of Western philosophy, encompassing morality, aesthetics, logic, science, politics,
and metaphysics.
When the Iranian-German philosopher and physician Kazem Sadegh-Zadeh (born
1942 in Tabriz, Iran, Fig. 3.1 (a)) proclaimed his “Goodbye to the Aristotelian
Weltanschauung” (Fig. 3.1 (b)) in the first year of our new millenium [69] he tar-
geted the foundations of this world view that “had been laid by Aristotle himself
in his
Metaphysics
,
Organon
,and
De Interpretatione
. They would constitute over
more than two millenia the basic principles of classical reasoning in science, mathe-
matics, philosophy, religion, politics, law, ethics, and all other areas” [69, p. 4], and
Sadegh-Zadeh quoted the following text passages from the
Metaphysics
to represent
its principles:
(A) This will be plain if we first define truth and falshood. To say that what is in not,
or that what is not is, is false; but to say that what is is, and what is not is not, is
true ([6], Book IV, 1011 b 26-27.)
(B) By demonstration I mean ..., e.g. “everything must be either affirmed or denied”,
and “it is impossible at once to be and not to be” ([6], Book III, 996 b 27-30.)
(C) ... that is the most certain of all principles. Let us next state what this principle
is. “It is impossible for the same attribute at once to belong and not to belong to
the same thing and in the same relation” ([6], Book IV, 1005 b 19-23.)
(D) Nor indeed can there be any intermediate between contrry statements, but of one
thing we must either assert or deny one thing, whatever it may be ([6], Book IV,
1011 23-24.)
(E) Further, an intermediate between contraries will be intermediate either as grey
is between black and white, or as “neither man nor horse” is between man and
horse ([6], Book IV, 1011 b 29-32.) ... Again, there will also be an intermediate
in all classes in which the negation of a term implies the contrary assertaion; e.g.
among numbers there will be a number which is neither odd nor not-odd. But
this is impossible ... ([6], Book IV, 1012 a 8-11.)
(F) Again, unless it is maintained merely for agument's sake, the intermediate must
exist beside all contrary terms; so that one will say what is neither true nor false.
And it will exist beside what is and what is not; so that there will be a form of
change beside generation and destruction ([6], Book IV, 1012 a 5-8.)
Sadegh-Zadeh elucidated that (A) is the so-called correspondence concept of truth,
that provided a basis for the correspondence theory of truth, and for Alfred Tarski's
semantics of two-valued logic; the first part of (B) shows the principle of the two-
valuedness; the second half of (B) and also (C) give Aristotle's version of the law
of non-contradiction; in (B) and also in (D) we have formulations of the law of
excluded middle; in (E) Aristotle advocated the two-valuedness because if theree
would exist more than two values then we could suppose that there is no sharp border
between its members and non-members. This, Aristotle said, is impossible! Finally,
in (F) Aristotle refused the existence of something between being and nonbeing.
This is called “Aristotelian ontology”.
